Fibre & polymer reinforcement of expansive clay soils

FIBRE & POLYMER REINFORCEMENT OF EXPANSIVE CLAY SOILS Project Report – 2016 Term 1 ENEG14005 – Engineering Project Implementation The use of reinforcement techniques within soil structures dates back in history to Roman times. Over the years, this technique has been further studied to aid in the improvement of foundations for roads and buildings. The use of fibres is a recent discovery requiring more research and trials. Fibre reinforcement not only looks to enhance the soil foundation, but also vies as an economically and environmentally friendly solution within the engineering world. The addition of polymers looks to benefit a soils strength by binding together the test specimen’s coarse materials.

Matthew Ouston [email protected] S0158615

Final Year Project Report

EXECUTIVE SUMMARY The following report has been created as part of the students requirements for the sucessful completion of a Bachelor of Engineering (Honours) Degree at Central Queensland University. The planning stage of this project was covered in a previous term, where a project outline, description, literature review as well as methodology. During the implimentation phase; testing, analysis and conclusions were prepared and finalised. This project looks towards tests and observervations of the change in strength for expansive clay soils when additives of fibres and polymers are mixed to create a new soil specimen. The use of stabilisation and reinforcement technqiues have been utilized in the modern world for centuries, however, fibre and polymer reinforcement is only now gaining momentum within industry practice and therefore the engineering properties and improvements that they provide on various types of soil specimens have not fully been tested and developed. An expansive clay soil was gathered from a property located outside of Sarina, Central Queensland. Tests previously covered on this soil type were backed up with initial testing undertaken, displaying the soils expansive properties, allowing it to be applied for this project. Fibre reinforcement and polymer stabalisation testing using Unconfined Compressive Strength testing was carried out on the soil samples, defining the optimum limits for the following types:

   

Clay Soil – at 9 different densities & moisture contents, narrowing down to greatest density and lowest density, no admixtures Clay & Fibre – clay samples mixed with fibre at contents of 0.25% and 0.5% fibre Clay & Polyvinyl Alcohol (PVA) – clay samples mixed with 5 percentages of PVA (0.1, 0.3, 0.5, 1.0 & 1.5%), determining the optimum amount for each density tested Clay, PVA, Fibre & BTCA – clay samples mixed with the optimum PVA content, along with trials of fibre at both 0.25% and 0.5%, cross-linked with BTCA at 0.1, 0.3 & 0.5%, determining the optimum mixture

The initial clay soil was tested with a one day curing time, allowing the maximum density at a certain moisture content to be calculated, along with the lowest density at a set moisture content. These two densities & moisture contents were chosen for further testing, to view how the fibre reinforcement and polymer stabilisation reacted for the two types of soil specimen. Further testing was carried out with two separate curing times to further test how a time lapse affected the samples. The curing time was set at 1 and 14 days, displaying the strength changes between a two week period. These tests indicated that a longer curing time helped increase the soils strength. Mainly due to the clay being able to fully absorb the moisture within the sample evenly, while also binding with the admixtures more thoroughly. It may be concluded that the completed testing displayed that for the high density, low moisture content samples, fibre reinforcement was a promising reinforcement, increasing the strength with the increase in fibre. While the low density, high moisture content samples increased best with the PVA additive at a high dosage, improving the soils naturally low shear strength very significantly.

Matthew Ouston  S0158615  CQUniversity [email protected]

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ACKNOWLEDGEMENTS This project would not have been possible without the guidence, supervision or technical support of Dr. Mehdi Mirzababaei. The patience and insight that he has shown towards me within this project has been crucial in allowing me to understand the application method of approriate testing measures, as well as understanding the output data for the reasoning behind my results. Due to this, I would like to offer my sincere appreciation to Mehdi for his assistance during this project. A special thankyou to Paula and Travis Frame for allowing timely access to the laboritories and equipment needed for the testing phase of this project. Considering the amount of tests needing to be completed and the time frame for them, I could not have completed the appropriate amount of tests without their assistance and direction. Along with the CQUniversity staff, further recognition is needed for Michael Currie, Dion Roser and the other members of the Department of Transport and Main Roads Rockhampton Laboratory staff for their assitance and friendly nature while preparing the soil specimen through the use of their LA Abrasion Machine. This was a large part of the initial stage for the project, as it allowed Mark and myself to quickly prepare the soil samples and commence testing much earlier than initially planned. Finally, I would like to thank Mark Aldava, who is completing his Bachelor of Engineering Degree alongside of me at Central Queensland University. Mark and I completed the initial soil tests for this proejct together, as we were both looking at using the same sample for our projects. Without Mark I would have taken much more time beginning my testing, as well as understanding the soil results we gathered. I wish Mark the best of luck with his own Thesis and wanted to make sure he knew what a vital role he played within my completion of this project.


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TABLE OF CONTENTS TABLE OF CONTENTS............................................................................................................................... 3 LIST OF FIGURES ...................................................................................................................................... 5 LIST OF TABLES ........................................................................................................................................ 7 GLOSSARY................................................................................................................................................ 8 1.0

INTRODUCTION ........................................................................................................................... 9

1.1

PROBLEM STATEMENT .......................................................................................................... 10

1.2

PROJECT DEFINITION ............................................................................................................ 10

1.2.1

AIM ................................................................................................................................ 10

1.2.2

OBJECTIVES ................................................................................................................... 11

1.2.3

SCOPE ............................................................................................................................ 11

1.3

LIMITATIONS ......................................................................................................................... 12

1.4

SUCCESSFUL OUTCOMES ...................................................................................................... 12

2.0

LITERATURE REVIEW ................................................................................................................. 13

2.1

VIRGIN FIBRE ......................................................................................................................... 13

2.2

EXPANSIVE CLAY SOILS.......................................................................................................... 16

2.3

UNCONFINED COMPRESSIVE STRENGTH OF COMPACTED MATERIALS (UCS) ..................... 17

2.4

POLYVINYL ALCOHOL (PVA) .................................................................................................. 18

2.5

1,2,3,4 BUTANETETRACARBOXYLIC ACID (BTCA) .................................................................. 21

3.0

METHODOLOGY ........................................................................................................................ 22

3.1

DEFINE PROJECT .................................................................................................................... 22

3.2

SOIL PREPARATION ............................................................................................................... 22

3.3

COMPACTION TESTING ......................................................................................................... 24

3.4

ATTERBERG LIMIT TESTING – PLASTIC & LIQUID LIMITS ...................................................... 25

3.5

UNCONFINED COMPRESSIVE STRENGTH OF COMPACTED MATERIALS ............................... 27

3.5.1

SAMPLE PREPARATION ................................................................................................. 27

3.5.2

SAMPLE COMPACTION.................................................................................................. 31

3.5.3

SAMPLE TESTING........................................................................................................... 32

3.6 4.0

SOAK TEST ............................................................................................................................. 33 RESULTS & DISCUSSION ............................................................................................................ 34

4.1

INITIAL SOIL SAMPLES ........................................................................................................... 34

4.2

HIGH DENSITY ....................................................................................................................... 38

4.3

LOW DENSITY ........................................................................................................................ 43

4.4

DISCUSSION........................................................................................................................... 48

4.4.1

UNCONFINED COMPRESSIVE STRENGTH ...................................................................... 48

4.4.2

NATURAL BEHAVIOURS UNDER FAILURE LOAD ............................................................ 55


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Final Year Project Report 4.4.3

FAILURE TYPE ................................................................................................................ 58

4.4.4

SOAK TEST ..................................................................................................................... 60

4.4.5

COSTING ........................................................................................................................ 62

5.0

CONCLUSION ............................................................................................................................. 66

6.0

RECOMMENDED FURTHER STUDIES ......................................................................................... 68

7.0

REFERENCES .............................................................................................................................. 69

7.1

WORKS CITED ........................................................................................................................ 69

7.2

KNOWLEDGE BASED RESOURCES ......................................................................................... 71

8.0

APPENDICES .............................................................................................................................. 72

TABLE OF APPENDICES ...................................................................................................................... 72 APPENDIX A - Stage One Competency Reflective Paper................................................................... 73 APPENDIX B – Technical Poster......................................................................................................... 75 APPENDIX C – Master Fiber 11 ......................................................................................................... 76 APPENDIX D – MSDS Polyvinyl Alcohol ............................................................................................. 77 APPENDIX E – MSDS Butanetetracarboxylic Acid ............................................................................. 82 APPENDIX F – Soil Preparation.......................................................................................................... 89 APPENDIX G – Compaction Data ....................................................................................................... 91 APPENDIX H – Atterberg Limit Testing.............................................................................................. 92 APPENDIX I – Sample Preparation Spreadsheet ............................................................................... 93 APPENDIX J – Test Results ................................................................................................................. 94 APPENDIX K – Initial Soil Trials .......................................................................................................... 96 APPENDIX L – Risk Assessment – Testing.......................................................................................... 98 APPENDIX M – Plant & Equipment Risk Assessment ...................................................................... 104 APPENDIX N – CQU Resources Agreement ..................................................................................... 113


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LIST OF FIGURES FIGURE 1 – Example of clay UCS with Fibre Additive FIGURE 2 - Virgin Fibre – “Master Fibre 11” FIGURE 3 – Advanced Triaxial Machine FIGURE 4 – PVA Chemical Structure FIGURE 5 – Polyvinyl Alcohol in Dry Solid State FIGURE 6A – 1,2,3,4-Butanetetracarboxylic Acid Structure FIGURE 6B – BTCA in Dry Solid State Form FIGURE 7 – Site Location FIGURE 8 – Los Angeles Abrasion Machine FIGURE 9 – Soil Sample after Preparation FIGURE 10 – Compaction Curve of Tested Expansive Clay Soil FIGURE 11 – Atterberg Limits FIGURE 12 – Test Specimen Preparation Spreadsheet FIGURE 13 – Prepared Soil Sample at 17% Moisture Content FIGURE 14 – Fibres being Pre-Prepared through Soaking FIGURE 15 – Fibres being added to Soil Sample FIGURE 16 – Hot Plate with PVA Solution FIGURE 17 – PVA Solution at 0.3% FIGURE 18A – Sample Compactor / Extractor FIGURE 18B – Compacted Clay Sample FIGURE 19 – Triaxial Testing Machine FIGURE 20 – Sample Failures FIGURE 21 – Sample Name Configuration FIGURE 22 – Initial Soil Trials – Axial Force vs Axial Displacement FIGURE 23 – Initial Soil Trials – Stress / Strain Graph FIGURE 24 – Average Results – High Density Samples FIGURE 25 – Average Results – Optimum High Density Sample FIGURE 26 – Average Strength Gain for High Density Samples FIGURE 27 – Average Results – Low Density Samples FIGURE 28 – Average Results – Optimum Low Density Sample Matthew Ouston  S0158615  CQUniversity [email protected]

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Final Year Project Report FIGURE 29 – Average Strength Gain for Low Density Samples FIGURE 30 – Comparison of Soil and Fibre Samples – High Density FIGURE 31 – Soil Sample with 0.5% Fibre Additive FIGURE 32 – Comparison of Soil and PVA Samples – High Density FIGURE 33 – Comparison of Soil and Optimum Samples – High Density FIGURE 35 – Low Density Sample being Pressed Downwards FIGURE 36 – Comparison of Soil and Fibre Samples – Low Density FIGURE 37 – Low Density Polymer Trials – Curing Time Comparison FIGURE 38 – Prepared PVA Sample vs Prepared Clay Sample FIGURE 39 – Three Types of Low Density Samples FIGURE 40 – Comparison of Soil and Optimum Samples – Low Density FIGURE 41 – Stress vs Strain Comparison of Initial Clay Specimens FIGURE 42 – High Density Samples with Fibre – Low Density Samples with PVA FIGURE 43 – Energy Absorbed before Failure – High Density Fibre Samples FIGURE 44 – High Density Samples Failing – Brittle FIGURE 45 – Change from Brittle Failure to Ductile Failure – Fibre Reinforcement FIGURE 46 – Low Density Samples – High Ductility – Shear Plane Failure FIGURE 47 – PVA Low Density Samples Failure FIGURE 48 – Layout of Soaked Samples FIGURE 49 - 5 Minutes into Soak Test FIGURE 50 – 30 minutes into Soak Test FIGURE 51 – Low Density Samples Slaking – Evidence of Slaking FIGURE 52 – UCS Soak Test Results FIGURE 53 – Low Density Soak Sample Before and After Triaxial Test FIGURE 54 – UCS and Cost of Options – Low Density FIGURE 55 - UCS and Cost of Options – High Density FIGURE 56 – Dry Density Results for Sarina Soil Sample FIGURE 57 – Dry Unit Weight for Sarina Soil Sample FIGURE 58 – 63 – Initial Soil Trials A FIGURE 64 – 66 – Initial Soil Trials B


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LIST OF TABLES TABLE 1 - Glossary TABLE 2 – Polypropylene Fibre Properties TABLE 3 – Advantages/Disadvantages of Fibre Reinforcement TABLE 4 – Soil Foundation Outline TABLE 5 – Polyvinyl Alcohol Properties TABLE 6 – BTCA Chemical Properties TABLE 7 – Soil Properties TABLE 8 – Soil Preparation Variables TABLE 9 – Initial Soil UCS Tests Configuration TABLE 10 – Initial Soil Specimen Details TABLE 11 – High Density Test Results TABLE 12 - Average UCS & Strength Increases for High Density Samples TABLE 13 – Outline of Sample Mixtures in Series TABLE 14 – Low Density Test Results TABLE 15 - Average UCS & Strength Increases for Low Density Samples TABLE 16 – Outline of Sample Mixtures in Series TABLE 17 – Cost of Individual Additives TABLE 18 – Low Density / High Moisture Content – Foundation Options TABLE 19 – High Density / Low Moisture Content – Foundation Options TABLE 20 – Total Mass of Soil Sample TABLE 21 – Moisture Contents Samples – Week 6 TABLE 22 – Moisture Content Samples – Week 8 TABLE 23 – Bulk & Dry Density of Soil TABLE 24 – Moisture Compaction Data TABLE 25 – Dry Unit Weight TABLE 26 – Penetration Readings TABLE 27 – Penetration & Moisture Content Data TABLE 28 – Plastic Limit Data TABLE 29 – Sample Preparation Spreadsheet TABLE 30 – High Density Tests & Results TABLE 31 – Low Density Tests & Results TABLE 32 – Risk Assessment - Testing TABLE 33 – Plant & Equipment Risk Assessment


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GLOSSARY Term AS Atterberg Limits Test BTCA

Definition Australian Standards Plastic and Liquid Limit Tests 1,2,3,4 Butanetetracarboxylic Acid

CBR California Bearing Ratio CQU Central Queensland University LL Liquid Limit MDD Maximum Dry Density MDR Moisture Density Relationship OMC Optimum Moisture Content PI Plasticity Index PL Plastic Limit PVA Polyvinyl Alcohol TPR Thesis Planning Report UCS Unconfined Compressive Strength

Virgin Fibre Virgin Homopolymer

Polypropylene Monofilament Fibre – Master Fiber 11

TABLE 1 - Glossary


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1.0 INTRODUCTION Soil reinforcement is a procedure that allows the engineering properties of soil, such as bearing capacity, shear strength, porosity, etc. to be improved through application of various elements. Reinforcement materials can vary greatly, from natural elements of bamboo or tree roots, to waste fibres and fibreglass. Reinforcement of soil can be traced back in history. The Roman Empire improved pathways natural bearing capacity by mixing additives such as calcium or limestone to soft soils (Ellaby[1]), techniques that are still applied in the modern world today. On the other hand, reinforcements such as tree roots or branches can be seen within the natural environment, aiding in the general strength of the surrounding soil. Throughout the years, geotechnical engineering has become more and more advanced, looking to test various designs of reinforced soil for the potential improvement in strength and other qualities. Soil reinforcement is a technique that is applied individually or together with stabilizing agents to allow a particular soil type to be improved for a particular purpose. Within current times, fibre reinforcement is being researched and tested more and more, as this is generally unchartered territory in the world of soil improvement. There are several main types of soil reinforcement; the use of cement, lime, chemicals, fibres or polymers can aid in the increase of the load bearing capacity of the soil through the improvement of the compressive strength. This increase in the load bearing capacity allows the soil to be utilized to support greater force from foundations or pavements.

FIGURE 1 – Example of clay UCS with Fibre Additive (http://newsroom.uts.edu.au/news/2014/11/uts-researchers-give-unstable-soils-carpeting[2])


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1.1

PROBLEM STATEMENT

The construction of roads quite often occurs in areas consisting of unsuitable and unsatisfactory soils, such as highly expansive clays. These soils have been responsible for a considerable amount of pavement failure due to the fact that they expand and contract with the fluctuation of moisture content and contain inherently poor strength properties (Budhu, 2011[3]). The availability of natural soil across the globe allows it to be used as a low cost option for all types of engineering and construction purposes. However, as soil is a complex material, it is often unsuited to the general requirements of the project at hand. This is where choices for a project need to be made, taking into account feasibility and time. The choices are to either, replace the current soil for more appropriate material, use the soil at site and revaluate the design of the project to suit the material given, or to alter the properties of the current material. Altering the properties of the surrounding soil is generally the cheaper option, rather than changing the project design or to even remove and replace new soil on site. The alteration of soil properties is called Soil Reinforcement. This is where geotechnical engineering is most useful, as it allows the combination of soil and a non-reactive material to increase the bearing strength of the site. The use of polymers to reinforce the soil is the most modern option in the area of geotechnical engineering, and therefore more testing and research is needed to find the best methods and results for real world industry to adapt standards to apply this practice better.

1.2

PROJECT DEFINITION 1.2.1

AIM

The aim of this research report was to test the improvement of the compressive strength of expansive clay soils at a high and low density through fibre and polymer reinforcement techniques. The chosen polymer of polyvinyl alcohol (PVA) was combined with 1234 butanetetracarboxylic acid (BTCA), which was applied as a cross-linker for the selected virgin fibres. The aim was to increase the strength of the expansive clay soil recovered from the surrounding Mackay Region. The results have been compared to the original results of the expansive clay soil, allowing judgements to be made on the qualities that the added fibre and polymer contents provide.


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1.2.2

OBJECTIVES

This project has been completed through the application of these steps: I. II. III. IV. V. VI. VII. VIII. IX. X. XI. XII.

Attaining matching expansive clay soil from the identical site as previous projects covered Prepare the soil sample for initial testing Complete initial testing for OMC and MDD of selected soil through Compaction Tests Test soil samples for LL, PI & PL Test soils natural UCS limit at various moisture contents and densities through the use of a Triaxial Machine Select the highest and lowest MDD rated samples for further testing Create a practical method for mixing fibre and polymers into the soil sample for UCS testing Complete UCS testing with fibre additives Complete UCS testing with PVA additives Complete UCS testing with Optimum Fibre and PVA contents mixed with BTCA Compare results gathered from numerous tests (utilizing various fibres, polymer and moisture content mixtures) Give final verdict of testing procedure and the output of the project

These objectives allow the findings between the increases in shear strength of an expansive clay soil when virgin fibres and polymers are added separately and also together to be displayed. Furthermore, these reinforcement types are able to be considered in a practical sense, looking at costing and work compared to increase in strength for foundations.

1.2.3

SCOPE

This project was chosen to be conducted through Central Queensland University in conjunction with previous research projects in the geotechnical engineering specific field. Soil reinforcement is constantly applied in large industry projects, with various soils requiring different types of reinforcement. This implementation report demonstrates the key objectives and methods that were aimed at from the start of the project, as well as the results found from the testing procedures, which help detail the usefulness of fibre and polymer reinforcement within soil specimens. Finally, outcomes from this project are discussed and considered for real world application. These results have the possibility of being able to be further tested and looked at to be applied to standard measures of soil reinforcement if feasible.


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1.3

LIMITATIONS

As this is a university project, the final completion date is the end of Term 1, June 2016. This therefore means that not all aspects can be covered in full, as there are many variables to consider, including direct industry application, the longevity of the fibre and polymer mixture within soil, as well as the various types of soil, fibres, polymers, cross linkers, tests and applications. As a result, for this project to lead to direct industry application, further research and testing may be needed, as well as other aspects taken into account.

1.4

SUCCESSFUL OUTCOMES

A successful outcome within this project would be to find positive strength increases for the selected soil samples, outlining the uses of each admixture applied and how best to implement these into real world design, taking into account not only strength increases, but also failure types and costing for the project.


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2.0 LITERATURE REVIEW Soil reinforcement is a method applied within geotechnical engineering where the engineering properties of the soil, such as plasticity, porosity, shear strength, etc. are altered, allowing the soil sample at hand to be more suited to the needs of the construction foundation. Reinforcement is looked at within projects as a way of avoiding soil replacement treatment, as if the soil is able to be raised to meet the needs of the construction, it is more economically viable than the replacement, as costing for removal and addition of soil to the site, along with the time taken to do so are greater than the reinforcement technique, sanctioning economic advantages.

2.1

VIRGIN FIBRE

The use of virgin fibres for soil reinforcement within industry is defined as a soil mass that contains randomly distributed fibres that in turn, enhance the strength of the soil sample. Within this project, the fibre to be applied is polypropylene fibres, which are found in carpets. These fibres will be applied to the expansive clay soil in a randomly distributed method, then tested through the unconfined compressive strength testing for compacted materials.

Properties Virgin Homopolymer Polypropylene Monofilament Fibre 0.91 0.034 19 620 – 755 ASTMC – 1116 White Nil $25 / kg TABLE 2 – Polypropylene Fibre Properties

Material Form Specific Weight (g / cm3) Average Diameter (mm) Average Length (mm) Tensile Strength (MPa) Compliance Colour Acid / Alkali Resistance Cost

Fibre is a material with a relatively high tensile strength; displayed within Table 2, which is then mixed with soil and possibly polymers, allowing the soil to apply the tensile resistance of the fibres to the sample, which then allows the soil to have a greater strength. The method first became prevalent when it was found that the fibres can act similarly to that of plant roots or natural occurring elements within soil, binging the soil together, assisting the expansive clay soil to increase its effective stress. Within this project, the use of polypropylene fibre in soil reinforcement will be tested. The type of fibre we are looking at applying will be gathered to have a uniform diameter and length; displayed in Table 2, which will make sure results for all tests have a common denominator, allowing them to be compared relative to each other. Fibre reinforcement in industry is seen as a large step forward in not only reinforcement, but also utilizing waste. In a study carried out by the Australia Bureau of Statistics, a total of 500,000 plus tonnes of textiles were dumped within 2009. This is seen to continue to grow as the population does. Therefore, the use of these fibres is seen as an environmentally friendly solution. A further study divulged that approximately 40% of this waste was that of polypropylene fibre (Waste Account, Australia[4]). This is a large reason why my project will be based around the use of this fibre in reinforcement testing.


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Final Year Project Report Polypropylene fibre has a specific gravity of 0.91 and a water absorption of 0.3% with the water not affecting the strength of the fibre; along with being approximately 60% of synthetic carpet wastes (M. Mirzababaei, M. Miraftab & M. Mohamed, 2012[5]). The fibre has a specific weight of 0.91 g/cm3 (Syntechfibres.com [6]), meaning it has little to no effect on the weight of the soil sample it is applied to. This particular fibre is manufactured in two forms. The main industrial use is monofilament, which are individual fibres in a cylindrical shape. The second is fibrillated, which are flat and intertwined. These fibres separate during mixing and compacting.

FIGURE 2 - Virgin Fibre – “Master Fibre 11” For this project, the polypropylene fibres to be used are “MasterFiber 11”, supplied from a company named BASF. This fibre is a virgin homopolymer monofilament fibrous reinforcement, which offers long term durability along with reducing the formation of shrinkage cracks and settlement shrinkage. The recommended uses of this fibre are within concrete mixes, however, within this project, the fibre will be directly applied to the clay soil. The facts for this type of fibre are displayed in the details sheet included within Appendix 8C of this report. Within the report produced on “Strength and Stiffness Response of Itanagar Soil Reinforced with Arecanut Fibre (Uni, Ram, Padu, Yachang, Singh 2014[7]), fibre contents of 0.25, 0.5, 0.75 & 1% were applied to their samples of a high density, low moisture content soil. From this, it can be seen that the higher the fibre content, the larger the strength increase produced from the stress/strain graphs, outlining UCS increases. The study reported that 1% fibre was difficult to mix within the soil samples and did not always give results. Therefore, from this, the idea to use contents of 0.25 and 0.5% fibre was decided upon. The study will be compared to the results gained within this project for the high density, low moisture content samples, as well as allowing the fibre reinforcement at these stages to be assed when mixed within a low density, high moisture content sample. Fibres are utilised within concrete as reinforcing and shrinkage control (Concrete Countertops Blog[8]). PVA fibres can be used for shrinkage control, however, they may not be able to fully replace reinforcing steel, but they do allow the improved mechanical properties of cured concrete, boosting its tensile strength. Advantages Disadvantages Cost effective (compared to other materials) Lack of Scientific Standard Weather conditions do not affect construction Clumping of Fibres (compared to stabilization methods lime, cement, etc.) Acts like natural elements (tree roots) Adhesion of Fibre – Soil Widely available (waste product) Long term useability of fibres TABLE 3 – Advantages/Disadvantages of Fibre Reinforcement Matthew Ouston  S0158615  CQUniversity [email protected]

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Final Year Project Report Laboratory test results showed that longer fibres increased the strength and toughness the most for a clay treated only with fibres. For a clay treated with fibres in addition to a chemical stabilizer, shorter fibres increased toughness the most, but the fibres had little effect on strength. Higher dosage rates of fibres had increasing effectiveness, but mixing became difficult for fibres contents above 1%. Poly(vinyl) alcohol (PVA) fibres were anticipated to perform better than other inert fibres due to hydrogen bonding between the fibres and clay minerals, but these fibres performed similar to other fibres (Rafalko, 2007[9]) The results of a study conducted by Jian Li, Chaosheng Tang, Deying Wang, Xiangjun Pei & Bin Shi in 2014 about fibre reinforcement and the increase of tensile strength within soft clay soils, it can be seen that as fibre was added at a 0.2%, the tensile strength increased at 65.7% from the original tensile strength of the soil (Li, Tang, Wang, Pei, Shi 2014 [10]). Along with this, the study outlined that the greater the dry density of the soil, the greater the increase in the tensile strength (Sciencedirect.com [11]). From this data, it can be seen that the tensile strength increases when fibre is applied. My project aims to detail the change in compressive strength with fibre applied to the soft soil clay.


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2.2

EXPANSIVE CLAY SOILS

As previously stated, one of the world’s most available resources for building and construction is soil. However, not all soil is the same, and therefore some types of soil can be more user friendly than others. Expansive or soft clay is a type of soil that is not user friendly when it comes to strength or suitability for foundation supports, as its bearing capacity is quite low, and can be affected heavily by changing weather conditions, causing it to be weaker than originally tested. When starting a new construction, the cheapest option is to build on the soil located at that site, and this is where reinforcement or stabilization comes into play, as adding certain elements or compounds to the existing soil is a more viable solution than replacing the soil with an alternative from a different source. Different designs require different bearing strengths, or other elements, and this is why there are so many different choices when it comes to reinforcement or stabilization. Soil Suitability for Foundation Support Best Very Good Good Poor Undesirable Unsuitable

Bed Rock Sand and Gravel Medium to Hard Clay Silts and Soft Clay Organic silts / Organic clay Peat TABLE 4 – Soil Foundation Outline

Generally, the mass density of basic soft clay soils range between 1.6-1.9 (t/m3) and has a typical value of 1.75 (t/m3). When a cohesive soil has a constant stress applied to it, the soil can deform plastically, which is what often causes events such as landslides. The testing involving the addition of fibres and polymers would help stop this. Various types of tests will be carried out on the soft soil clay, beginning with drying the soil and passing it through a 2.36mm sieve. The clay will then undergo compaction testing to find the maximum dry density using different moisture contents as described within the methodology. The plastic and liquid limit testing will then find the plastic index of the soil. From this, the main testing will be undertaken, testing the unconfined compressive strength, applying different percentages of fibres and polymers, finding what is the most beneficial for this particular clay soil. The Australian Standards methods for testing will be used, as displayed below:

  

AS 1289.5.2.1 (2003) – Soil Compaction and Density Tests [12] AS 1289.3.9.1 (2002) – Soil Classification Tests [13] AS 1141.51 (1996) – Unconfined Compressive Strength of Compacted Materials [14]


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2.3

UNCONFINED COMPRESSIVE STRENGTH OF COMPACTED MATERIALS (UCS)

The unconfined compression test aids in measuring the shearing resistance of cohesive soils. This is done by applying an axial load through means of a triaxial machine system. The unconfined compressive strength of the soil can be defined as the maximum amount of stress obtained within the first 15% of strain. Description on how the UCS is carried out is displayed within the methodology of this report, along with further description on uses and application of results.

FIGURE 3 – Advanced Triaxial Machine CQUniversity Laboratory Equipment


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2.4

POLYVINYL ALCOHOL (PVA)

Poly(vinyl) Alcohol (PVA) is the largest synthetic biodegradable and water soluble polymer produced in the world (Ding et al., 2002; Shi et al., 2008[15]) and is mainly applied within papermaking and textiles as a reinforcement agent. It is a type of polymer, which can be described as chemical compounds made up of large, multiple-unit molecules, although PVA is created by dissolving a polymer (Polyvinyl Acetate) in an alcohol substance such as methanol, then treating it with a catalyst of alkaline quality such as sodium hydroxide (About.com[16]). Poly(vinyl) Alcohol can be seen to be gathered from poly(vinyl) Acetate, which leads to the chemical structure as detailed in Figure 4.

FIGURE 4 – PVA Chemical Structure PVA will be applied within my project as a single additive, in addition to the use of virgin fibres and also cross-linked with BTCA. PVA comprises of hydroxyl groups (OH), meaning that they have the ability to bond using their hydrogen molecules with other molecules, which causes a change in surface bond strength. It is a colourless and odourless nontoxic solution that biodegrades slowly. A materials safety data sheet for polyvinyl alcohol is included within Appendix 8D of this report.

FIGURE 5 – Polyvinyl Alcohol in Dry Solid State PVA is offered in granule and powdered forms, based in a dry solid state (displayed within Figure 5 above), having a specific gravity ranging between 1.2 – 1.3 (1200 – 1300 kg/m3) with a bulk density between 0.5 – 0.7 g/ml. However, one of the most vital properties due to the various applications of PVA depending on is the degree of polymerization & degree of hydrolysis it has undertaken. A degree of polymerization describes the size of a polymer. The greater degree of polymerization the polymer is, the larger and longer the polymer will be (Perrychem [17]).


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Properties Polyvinyl Alcohol PVA ; PVOH (C2H4O)x 44.05 1.2 – 1.3 228 Yes White $264 / kg TABLE 5 – Polyvinyl Alcohol Properties

Chemical Name Synonym Formula Molecular Weight (g / mole) Specific Gravity (g / )cm3) Boiling Point (oC) Water Soluble Colour Cost

From this, it can be stated that the higher the degree of polymerization, the:

      

Higher viscosity of the solution Higher Adhesion Strength of film Less water soluble Higher solvent resistant Higher tensile strength Less penetration and softness Better protective ability

PVA is used in sizing agents that give greater strength to textile yarns and make paper more resistant to oils and greases (Encyclopaedia Britannica Online[18]). A sizing solution of 2-5% is generally applied. This is added with a plasticizer, an insolubilizer and a defoamer. The applications of PVA in the paper industry are; oil and grease resistance, clear surface sizing, binder for ink jet paper and more. Although, as demonstrated in (Xu et al., 2001[19]), PVA is not only applicable in sizing agents, but can aid in the improvement of the dry tensile index of paper based kraft pulp, while (Awada et al., 2015[20]) demonstrated that the combination of BTCA and PVA can improve tensile index on TMP fibres. Displaying that PVA can be applied to assist in a tensile strength increase. For this study, the type of PVA applications needed to be studied and replicated are those of its use in the Building Industry through Cement Additives. The PVA powder helps improve plaster properties such as flexibility, water retention, and increase plaster viscosity. Along with these features, it enhances the cements working capacity & quality, while also reducing the friction of the plaster. All of these, with the addition of the high anti-alkali characteristics of the PVA aid in prevention of cracking and shedding of the plaster, as well as improve the smoothness and adhesion of the cement mix (Perrychem [17]). The direct applications of mixing PVA as a cement additive can be seen within buildings materials as a binding material, such as a binder in gypsum or asbestos board. Therefore, this was the initial thoughts behind PVA aiding in the improvement of the expansive clay soil specimens characteristics, as it is weather resistant, chemical resistant, and has a superior tensile strength to that of most fibre products. It has been found that adding 1% PVA to 4% cemented sand, resulted in the peak strength from a UCS and axial strain test being increased by 2 times, compared to a no-fibre reinforced sample. (Hejazi et al., 2012[21])


19

Final Year Project Report Although studies have been carried out using PVA for construction, predominately the studies are based around cement stabilization. When it comes to the use of polyvinyl alcohol in soil reinforcement, more research is needed to further comprehend its limitations. This paper plans on doing this through mixing the PVA with fibres, as well as being applied directly to soil to allow comprehension of its geotechnical uses. Polyvinyl Alcohol has been shown to be an effective stabilizer of surface soils when the structural organization of the soil is maintained by the soil organic matter. In a journal published on the effect of PVA application into surface soil and the change in surface runoff vs soil loss, it was demonstrated that a surfaces acceptance of rainfall could be doubled through the use of 0.005% admixture of PVA weight/weigh with of soil surface (Tumsavas, Z. Tumsavas, F., 2011[22]). This study demonstrates PVA’s ability to bind soil together like an adhesive, allowing water to run over it without picking up particles within the runoff. Within this project, the PVA will be looked at to bind the soil samples together, allowing them to increase their shear strength.


20


2.5

1,2,3,4 BUTANETETRACARBOXYLIC ACID (BTCA)

This acid will be used as a cross-linker within the testing phase. It is an acid type known as carboxylic, which means it gives hydrogen ions, aiding in linking fibre and the polymer of PVA to the soil. The main reasoning behind the use of BTCA is that elements like virgin fibres can gain more consistency, allowing them to keep shape and become more cohesive with the soil sample. Along with this, the acid is pollution free, aiding in sustainable design. A materials safety data sheet for this acid is included within Appendix 8E of this report

FIGURE 6A –1,2,3,4-Butanetetracarboxylic Acid Structure

FIGURE 6B – BTCA in Dry Solid State Form

Properties 1,2,3,4 BUTANETETRACARBOXYLIC ACID BTCA C8H10O8 234.1602 196 No White $925 / kg TABLE 6 – BTCA Chemical Properties

Chemical Name Synonym Formula Molecular Weight (g / mole) Melting Point (oC) Water Soluble Colour Cost

The BTCA will be applied with three different percentages, and is basically only used to help link the PVA into the soil sample, as PVA is water soluble, meaning that it could wash out of the sample if not aided by BTCA. As can be seen, it is very expensive, so three percentages of 0.1, 0.3 & 0.5% w/w with water will be trailed to find how much is necessary to cross-link the PVA into the sample.


21


3.0 METHODOLOGY 3.1

DEFINE PROJECT

This project is based around the improvement of strength for expansive clay soils through the use of reinforcing and/or stabilizing agents. The reinforcement will be provided by a virgin fibre “MasterFiber 11”, while the selected polymers (PVA & BTCA) are applied as stabilizing/crosslinking agents, looking to bind the sample together and give a greater water insolubility and strength.

3.2

SOIL PREPARATION

The soil sample was obtained from a rural property approximately 3 kilometres from the town of Sarina, located in Central Queensland.

FIGURE 7 – Site Location The total soil specimen collected weighed approximately 150 kilograms. The soil was sampled through the use of the Australian Standards method (AS1289.1.1, 2001 [23]), and was bought to the Central Queensland Rockhampton Laboratories for preparation. To prepare the sample, the soil was sun-dried on tarpaulins for 3 days, with larger masses of clay being oven dried in accordance with Australian Standard (AS1289.1.2, 2005 [24]). After the drying of the specimen, the average moisture content was found to be 3.75%. Once dried, the sample then needed to pass through a 2.36mm sieve, which would allow it to be prepared and worked with easily. To aid in this, the Los Angeles Abrasion machine located at The Department of Transport and Main Roads was borrowed. This machine helps crush the dried clay into smaller particles, allowing them to pass through the designated sieve.


22


FIGURE 8 – Los Angeles Abrasion Machine After preparing the soil, the total mass of the remaining sample that had passed through the 2.36mm sieve was approximately 135 kilograms, which was spread throughout 8 buckets. These buckets were then individually tested for their moisture content, which would allow them to be used separately for future testing. As before, the average moisture content was approximately 3.75%, as displayed in Figure 9. Following this, the moisture content would be re-tested every fortnight, allowing for the correct value to be used while testing. All soil preparation data can be found tabulated within Appendix 8F of this report.

FIGURE 9 – Soil Sample after Preparation


23


3.3

COMPACTION TESTING

The soil is then tested for its MDD through the use of the Proctor Test method (AS1289.5.2.1, 2003[25]). This test allows the moisture content of the sample to be graphed against the calculated dry unit weight of the soil specimen, displayed in Figure 10, as well as within Appendix 8G. The proctor test was completed for 7 samples, with moisture contents of 10%, 18%, 25%, 30%, 35%, 45% & 50%. The soil was prepared by mixing the pre-calculated amount of water into the set weight of soil sample, and then left to cure for a minimum of 24 hours.

FIGURE 10 – Compaction Curve of Tested Expansive Clay Soil From the tables displayed within Appendix 8F, it can be seen the data collected from the proctor test used to create the compaction curve displayed in Figure 10. As this project is looking at the application of reinforcement in expansive clay soils, the data collected was to be on the wet side of the maximum density compaction curve, as this is when the clay is in its softest, and therefore weakest state. From the graph and the data collected, the maximum dry density of the clay was found to be at a maximum moisture content of 16.2%, reaching an approximate Dry Unit Weight of 16.9 kN/m3, with the lowest point of testing being at 48% moisture content as a compaction density of 11.2 kN/ m3. These two points would be chosen to conduct further testing on due to this thesis looking to analyse how the additives react at the strongest and a low compaction point. Due to these tests wanting to replicate real world conditions, the densities were taken at 98% of their value, bringing them to 16.2 kN/m3 and 10.8 kN/m3. The factors taken into account when conducting a compaction test on soil, is the ability of the soil to absorb moisture, the effort or force of the compaction applied to the soil, and the plasticity of the specimen.


24


3.4

ATTERBERG LIMIT TESTING – PLASTIC & LIQUID LIMITS

Atterberg Limit Testing allows the behaviour of the soil sample to be defined. It is done by enabling the classification of the soil to be completed by analysing its performance and comparing these results to a set standard. The liquid limit test carried out used 6 x 250g samples of the clay specimen that passed through a 425 micron sieve. This clay was mixed with distilled water to reach various moisture contents and left to cure for a minimum of 24 hours. The following day, the liquid limit tests were carried out in accordance to (AS1289.3.9.1, 2002[26]). A cone penetrometer gave results of a Liquid Limit of 58% for a 20mm penetration (Appendix 8H). This result, when combined with a Plastic Limit Test will give the overall Plasticity Index of the soil sample. The method followed is detailed by CQU in a sheet attached in my workbook which is based off the Australian Standards. The plastic limit is calculated through the use of the soil in its wet state being remoulded over a glass plate to a diameter of 3mm. The results that the plastic limit gave were an average of approximately 27%, shown in Table 9 of Appendix 8H. Therefore, the Plasticity Index was found to be: Plasticity Index (PI)

= Liquid Limit (LL) – Plastic Limit (PL) = 75% - 26.9% = 48.1%

The soil used within this project can be named a high plasticity clay, meaning it contains a high plasticity index. The term plasticity index (PI) refers to the difference between the Liquid Limit (LL) and the Plastic Limit (PL) of the soil in a classification system known as the Atterberg Limits (Budhu, 2001[3]). The Atterberg Limits are displayed in Figure 11 below:

FIGURE 11 – Atterberg Limits


25

Final Year Project Report Highly plastic clay soils are problematic within engineering design projects, as they possess a low shear strength, as well as a high compressibility (Budhu, 2001[3]). The high plastic clay soil has also been known to expand independently of the load applied, which creates more problems for construction design such as foundations. A previous investigation conducted by Bowler on the property outlined that the site was classified as a “Class H”, indicating that the soil was highly reactive, with large shrink/swell potential.

Properties Liquid Limit (%) Plastic Limit (%) Plasticity Index (%) Optimum Moisture Content (%) Max Dry Density (kN/m3) Site Class Specific Gravity (g / cm3)

75.0 26.9 48.1 17 16.9 H 2.71

TABLE 7 – Soil Properties


26


3.5

UNCONFINED COMPRESSIVE STRENGTH OF COMPACTED MATERIALS

A UCS test is a laboratory procedure that measures the strength and stress/strain relationship of soil or rocks that possess enough structural bearing to be tested unconfined.

3.5.1

SAMPLE PREPARATION

The initial stage of the UCS test is the preparation and curing of the soil sample. The soil must be measured out in its dry state to a set weight, with a calculated dosage of water to be mixed in to reach the set moisture content and also weight of the sample, meaning that when it is compacted, it will be able to match the set density for the test at hand. Within this project, I was able to achieve this by first developing a spreadsheet that outlined the factors included in the sample preparation, displayed in Figure 12 below and also Appendix 8I.

FIGURE 12 – Test Specimen Preparation Spreadsheet As can be seen, it takes into account all the possible variables associated with mixing the sample, outlined in Table 8:

Variables Units Mm kN/m3 % % g % g % g g % g TABLE 8 – Soil Preparation Variables

Compaction Height & Diameter Dry Unit Weight Moisture Content Fibre Content Fibre Mass PVA Content PVA Mass BTCA Content BTCA Mass Dry Mass of Soil Initial Moisture Content Total Mass of Sample

From this point, there were several stages that were dependant on what sample was being mixed.


27

Final Year Project Report 3.5.1.1 SOIL SAMPLES If the sample being prepared is a simple soil sample at given moisture content and density, then the sample is weighed out, and the appropriate amount of water is simply mixed in using a spray bottle until an even moisture content distribution at the set level is reached.

FIGURE 13 – Prepared Soil Sample at 17% Moisture Content 3.5.1.2 FIBRE SAMPLE An admixture of fibre made the preparation stage more difficult; as the fibre contains electrostatic properties, the strands stick together, creating balls of fibre and clay within the sample, giving an uneven distribution of fibre to clay. To stop this from occurring, several attempts were trailed to find the best way of giving an even distribution of fibre throughout the sample. The best solution found was to pre-soak the fibres in a tray of water, displayed within Figure 14. This water allows the fibres to lose their electrostatic charges and be able to be spread apart. The tray is then placed in the oven at a temperature of 55oC and left to dry overnight.

FIGURE 14 – Fibres being Pre-Prepared through Soaking


28

Final Year Project Report The fibres can then be taken out of the tray the next day, possessing much less electrostatic charges and having been separated well already. The soil specimen is then mixed up using the spray bottle and approximately 80% of the required water content. The remaining 20% water is sprayed onto the fibres to allow them to then be added into the sample and mixed thoroughly throughout the sample to create an even distribution of fibre and water content.

FIGURE 15 – Fibres being added to Soil Sample The fibre was added into the soil mixture at 2 different percentages; 0.25% and 0.5%. Within industry, some machines are used when mixing large soil samples with fibres, such as a concrete mixer, tumbler, etc. However, for this project, the fibres will be added in manually by hand as the samples are prepared. The real world application of the fibres within soil can be seen in pavement layers, retaining walls, earthquake foundation engineering, or railway embankments.


29

Final Year Project Report 3.5.1.3 POLYMER SAMPLE To prepare a sample containing PVA and/or BTCA, a solution of these polymers mixed with water had to be created. To do this, a litre of water was measured out, meaning that if a 1.5% PVA solution was needed, 15 grams of PVA would be added to this solution. It was found through researching a paper on the combination of polymers (Çay, Miraftab 2013[27]), that a solution of PVA or BTCA could be prepared by mixing it in water while heating the water to between 80-100oC for longer than an hour, or until the solution was clear.

FIGURE 16 – Hot Plate with PVA Solution

From here, the solution is left to cool down, then added into a spray bottle to then use as the addition water needed into the solution, shown in Figure 17, producing an even amount of PVA or BTCA necessary in the soil specimen. Finally, once the sample has be prepared, however the method suggests, it is then sealed in a plastic bag, placed in an airtight bucket and left to cure in a fridge for a day until compaction occurs. It is of extreme significance that all soil samples, even if unprepared, are stored in air-tight containers or bags whilst not being used. This is due to the occurrence of moisture loss or evaporation, which can create substantial changes within the output of results from testing. To create consistency, all samples when cured are placed within an airtight bag, which is then left in a sealed container, as consistency is of utmost important when testing a large amount of samples to be compared. The PVA was mixed up into 5 solutions of 0.1, 0.3, 0.5, 1.0 & 1.5% weight / weight with water.

FIGURE 17 – PVA Solution at 0.3%

All samples (soil, fibre and PVA) were trialled for 1 and 14 day curing times, giving results on how longer curing times affect each sample. Once the optimum solution of PVA was found for each density (16.2 & 10.8), it was then trialled further in “Optimum Trials”, which consistent of the optimum PVA solution, mixed with fibre (at both content levels of 0.25% and 0.5%), as well as adding in BTCA at three percentages (0.1, 0.3 & 0.5%). This then allowed the “Optimum” admixture to be found through the testing process. Outlining which solution of Fibre, PVA & BTCA reacted best for each density of the expansive clay soil.


30


3.5.2

SAMPLE COMPACTION

The compaction testing is carried out by knowing the desired height and diameter of the test specimen. The equipment used to compact the soil into a 50mm diameter x 100mm in length cylinder, is a “Sample Compactor/Extractor” which is set up vertically, displayed in Figure 18A. The soil sample is added to the tube from the top, while clamps at the other end seal off the tube, with a pore-stone also placed at the bottom to soak up seepage. The rod screws down through the tube and settles the soil into a height of the users choosing (100mm). This is left for 20-30 minutes to let set. Once set, the end cap is removed and the sample is pushed out the end of the tube. The finished sample is displayed within Figure 18B. The height and weight of the soil are taken before and after curing, to note the swelling. The method was followed according to Australian Standard (AS1141.51, 1996 [28]). A method sheet is attached within my workbook outlining the procedure.

FIGURE 18B – Compacted Clay Sample FIGURE 18A – Sample Compactor / Extractor Once again, once the sample is compacted, it is wrapped in cling-wrap and then placed within a sealed bucket for storage in a fridge (cool, dry environment) for the set amount of days (1 or 14 dependent on sample).


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3.5.3

SAMPLE TESTING

Following the preparation, compaction and curing of the soil sample, it is then placed onto the Triaxial Testing System, displayed within Figure 19, which works on a computer program named “Stress Path – Triaxial Testing System”. This program allows all the variables to be input, as well as tabulating the data collected.

This process works by placing the sample on a platform that will rise at a rate of 1 mm/minute, with the point load at the top, registering the amount of force applied to the sample. This tests runs until 20 mm displacement has been reached, or the sample has failed. Below in Figure 20 are examples of sample failure.

FIGURE 19 – Triaxial Testing Machine

FIGURE 20 – Sample Failures Once the test has been completed, the sample is placed in a tray with weight and total mass recorded, then placed in an oven to reach 0% moisture, allowing the actual moisture content of the sample to be calculated. This keeps up the consistency within the results. As a sample with a different moisture content would test differently, giving various results. The final step in testing is to convert the collected data to an excel file, allowing it to be analysed against the other test samples. Graphing increases and decreases in undrained shear strength, as well as finding trends throughout the testing phase.


32


3.6 SOAK TEST A soak test was designed to test how the various admixtures affected the soil specimen’s natural breakdown. The soil samples will be prepared for both densities as a clay-only sample, clay & fibre sample, as well as an optimum content sample containing fibre, PVA and BTCA. The samples will be soaked for 4 days (the same time period as a CBR soak test) and changes will be monitored throughout this period. Once the 4 days has concluded, remaining samples will be tested for remaining strength and also swell readings, looking to observe how being submerged changes the engineering properties of the soil specimens. The test was designed to understand how the variation in sample contents affected the soil breakdown. The fibre additive uses its tensile strength to hold the soil together, while the PVA binds the soil at the same time that the BTCA coats the sample, stopping the PVA from being washed out. The remaining strength will be checked, however, the main reasoning behind this test is to examine the use of BTCA within the optimum samples, as it is applied to cover the PVA and stop its natural water-solubility.


33


4.0 RESULTS & DISCUSSION The following section comprises of results based on the testing phase of this project, as well as analyses and outcomes of these results. In some cases, averages have been applied as outlier data was removed to allow the results to withhold the highest amount of consistency. All completed tests and their results have been tabulated and are displayed with Appendix J of this report.

4.1

INITIAL SOIL SAMPLES

The first stage of UCS testing within this project was analysing the 9 chosen densities and moisture contents samples and deciding upon which two would be chosen for further testing. The aim was to find the strongest and weakest samples within the 9 selected samples, meaning that further testing using fibres and polymers would help analyse the improvements for an expansive clay soil when at its strongest and weakest points. The 9 tests consisted of the following Sample types:

Test Moisture Content (%) 1 2 3 4 5 6 7 8 9

Density (kN / m3)

17 16.2 29 14.4 34 13 43 11.7 14 16.2 20 16.2 37 13 31 13 48 10.8 TABLE 9 – Initial Soil UCS Tests Configuration

These configurations were given test sample numbers that could be continued for all tests to come, outlining the Fibre, PVA and water content, as well as the density and sample number. Figure 21 below details this layout: 1.5% 0.1% PVA BTCA

17% MOISTURE CONTENT

0.25% FIBRE

25F 15P 01B 162D 17W 01C - 1 SAMPLE 1 16.2 (kN/m3) DENSITY

1 day CURING

FIGURE 21 – Sample Name Configuration This layout will be utilized for all tests conducted, as it is able to be used to identify each individual sample. Table 10 outlines the tests undertaken for the initial soil samples as well as the heights and masses of each sample.


34


Test No.

1

2

3

4

5

6

7

8

9

Sample No.

Initial Weight (g)

Preparation Height (mm)

Preparation Weight (g)

00F00P162D17W - 1 106 378.2 00F00P162D17W - 2 105.33 377.6 379.4 00F00P162D17W - 3 107.00 378.6 00F00P162D17W - 4 105 377.6 00F00P144D29W - 1 101.33 371.2 00F00P144D29W - 2 371.8 102 371.4 00F00P144D29W - 2 101 371.4 00F00P13D34W - 1 101 347.9 00F00P13D34W - 2 348.7 101 347.6 00F00P13D34W - 3 100 345 00F00P117D43W - 1 101 334.2 00F00P117D43W - 2 334.9 101 334.3 00F00P117D43W - 3 101 332.6 00F00P162D14W - 1 107 371.4 00F00P162D14W - 2 369.6 109 368.2 00F00P162D14W - 3 106 367.6 00F00P162D20W - 1 104 389.4 00F00P162D20W - 2 389.1 103 388.6 00F00P162D20W - 3 103 388.8 00F00P13D37W - 1 102 355.8 00F00P13D37W - 2 356.5 103 356 00F00P13D37W - 3 103 356.2 00F00P13D31W - 1 103 340.1 00F00P13D31W - 2 340.9 101 339.9 00F00P13D31W - 3 101 340.6 00F00P108D48W - 1 101 320 00F00P108D48W - 2 101 318 319.9 00F00P108D48W - 3 103 315.2 TABLE 10 – Initial Soil Specimen Details

Final Height (mm)

Final Weight (g)

106 104 107 105 101 102 102 101 101 101 101 101 100 107 109 106 104 103 103 103 103 103 103 101 101 101 101 101

378.1 377.4 378.4 377.5 370.6 371.2 371.2 347 347.2 345 332.7 332.6 331.2 371 368.1 367.5 389 388.4 388.8 355.8 356.2 356 340 339.6 340.4 319.9 318.2 314.4

As can be seen from Table 10, there were a total of 28 tests completed for the initial stage one trials. Each test is repeated 3 times, allowing for any inconsistencies or failures to be taken out, giving a more appropriate average for the results. All trials graphed as Axial Displacement (mm) vs Axial Force (N) are displayed within Appendix K. The most average trial from each test has been graphed and displayed in Figures 22 & 23 below:


35


FIGURE 22 – Initial Soil Trials – Axial Force vs Axial Displacement Figure 22 outlines the Force taken by each specimen, while Figure 23 displays the stress/strain relationship, outputting the UCS value for each given sample.

FIGURE 23 – Initial Soil Trials – Stress / Strain Graph


36

Final Year Project Report As can be seen within the above plotted graphs, Test 1 (16.2kN/m3 Density – 17% Moisture Content) performed the greatest, reaching approximately 1500 N of force, and a UCS value of approximately 700 kPa. While the lowest sample tested was Test 9, containing a moisture content of 48% and a density of 10.8, the lowest density and highest moisture content of all samples. It reached a limit of 18 N of force, and a stress value of 7 kPa. The trend within these graphs is that the lower the density & higher the moisture content, the less force and stress the sample can take. This is due to the lower density samples giving in easily when a force is applied, alternatively, the higher density samples try to withstand the force. The steep curve that can be seen on Tests 1, 5 & 6 clearly indicates the high density of the samples, as they quickly take much more force than any of the other trials. However, this may not necessarily be a positive thing, as the samples take a large force very quickly due to no room for give within the sample, creating a large shear force and failing early within testing. This is evident by all three trials failing before 5 millimetres of displacement, meanwhile, the other samples (lower in density) all last further than the maximum 15 millimetres of testing required. Therefore, it can be said that while the higher density materials with low moisture contents reach higher stresses, they are extremely brittle. Once they reach their failure point, they shear and drop their ability to take load extremely. While the low density, high moisture content samples continue to compress with the low forces they are absorbing, meaning they behave with great ductility. From this initial stage, this project has been narrowed down to analysing two sample densities of 16.2 kN/m3 at a moisture content of 17%, and a sample containing a density of 10.8 kN/m3 at a moisture content of 48%. Further testing, including 14 day trials, fibre and polymer admixtures, and trials for the optimum content of each will be found. These will be displayed and discussed within the below stages.


37


4.2

HIGH DENSITY

Table 11 on the following page contains all Triaxial testing that was covered for the high density samples, containing the UCS and Peak Load for each test, as well as factors such as the admixture content, curing time and dates, heights and moisture contents. The Peak Load was found during testing using the Triaxial Testing Machine, which allowed for all samples to have their UCS results calculated. As previously mentioned, outliers were eliminated from the “average UCS” calculation, allowing for consistent comparability of results.


38

Density (kN/m3)

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

Test No.

1

2

3

4

5

6

7


8

17 - 1

17 - 2

17 - 3

18 - 1

18 - 2

18 - 3

19 - 1

19 - 2

19 - 3

17

17

17

17

17

17

17

17

17

17

17

17

17

17

17

17

17

Moisture Content (%)

0.5

0.5

0.5

0.25

0.25

0.25

0

0

0

0

0

0.5

0.5

0.25

0.25

0

0

Fibre (%)

0

0.1 0.3 0.5 1 1.5

1

1

1

1

1

1

1

1

5

3

1

5

3

1

5

3

1

0

0.1 0.3 0.5 1 1.5

1

0

0

0

0

0

0

14

14

14

14

14

14

14

14

14

14

1

14

1

14

1

14

1

BTCA (%) Curing Time (days)

0

0

0

0

0

0

PVA (%)

3

3

3

3

3

3

3

3

3

1

1

3

3

3

3

3

3

Number of Samples Status

To-do

3/05/2016

27/04/2016

26/04/2016

29/03/2016

21/03/2016

6/04/2016

8/03/2016

6/04/2016

6/04/2016

4/05/2016

28/04/2016

27/04/2016

30/03/2016

22/03/2016

7/04/2016

9/03/2016

7/04/2016

7/04/2016

7/04/2016

30/03/2016

29/03/2016 6/04/2016

7/04/2016

Sample prep date

Curing

6/04/2016

Mix date

Complete

19/05/2016

13/04/2016

12/04/2016

14/04/2016

23/03/2016

22/04/2016

10/03/2016

22/04/2016

8/04/2016

22/04/2016

14/04/2016

8/04/2016

Test date

103 104 104 103 104 104 103 103 103 104

104 104 104 103 104 104 103 104 103 103

103 103 103 103 103 102 102 103 102 103 104 102 102 105

103 104 105 102 103 102 104 102 104

102 103 103 104 104 103 103 102 103

102 103 103 103 103 101 102 104 101 102 104 102 104 105

103 104 105 102 103 102 104 102 104

102 103 103 104 104 103 103 102 103

103 103 103 102 103

104 103 103

104 103 103

103 104 102 103 103

104 102 103

104 103 103

104 103 103 103 102 102

Height before test (mm)

Height after preparation (mm)

TABLE 11 – High Density Test Results

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

17.62 15.98 16.35 16.38 16.61 16.22 17.15 17.20 17.14

17.22 16.56 17.81 17.31 16.55 16.49 16.56 17.01 17.12

17.15 17.36 18.10 17.21 16.93 17.55 16.38 17.12 16.21

17.52 16.41 17.29 16.28 18.98

17.21 16.93 17.55 16.38 17.12

16.99 16.46 17.40

16.10 16.69 16.88 16.82

16.93 17.55 17.56

15.67 17.25 16.60

17.93 16.80 16.90

17.00 17.32 16.49

Diameter before Moisture content test (mm) after test (%)

1728.756 1881.498 1535.970 1310.205 1417.812 1442.077 1676.814 1619.255 1745.797

1735.796 1817.418 1518.577 1872.854 1640.309 1610.995 1735.119 1652.191 1727.895

1345.852 1217.031 1141.871 1435.115 1340.422 1431.417 1306.278 1254.766 1160.927

1059.850 1364.851 1398.290 1433.220 1167.520

1107.440 1165.230 985.847 1068.400 1001.200

2051.150 2057.600 1733.600

2074.030 1460.540 1635.970 2065.161

1725.470 1815.550 1562.670

1463.807 1659.187 1740.367

1279.210 1223.950 1253.880

1336.500 1063.760 1135.820

Load at Peak (N)

1680.622

1390.031

1715.408

1705.068

1708.053

1690.597

1240.657

1402.318

1234.918

1284.746

1065.623

1947.450

1808.925

1701.230

1621.120

1252.347

1178.693

Average Load at Peak (N) (kPa)

716.081 780.351 661.521 618.517 657.660 664.797 724.210 731.850 747.930

711.553 804.002 658.462 762.013 658.759 721.984 713.834 727.594 750.064

610.906 555.719 525.309 644.430 609.506 654.165 603.495 567.775 523.796

466.110 621.820 631.570 642.660 514.950

507.149 517.573 442.798 486.689 440.421

1003.020 993.320 833.960

873.190 621.900 699.230 878.790

839.760 887.410 759.390

588.351 696.671 804.945

563.400 562.220 630.120

614.950 481.050 531.160

UCS

734.663

646.991

719.318

730.497

714.252

724.672

565.022

636.034

563.978

573.160

478.926

943.440

768.278

828.860

696.656

585.250

542.387

Average UCS (kPa)


39

Final Year Project Report Series 1 2 3 4 5 6 7 8

Sample Mixture 00F00P00B162D17W01C 00F00P00B162D17W14C 25F00P00B162D17W01C 25F00P00B162D17W14C 50F00P00B162D17W01C 50F00P00B162D17W14C 00F10P00B162D17W01C 00F10P00B162D17W14C

FIGURE 24 – Average Results – High Density Samples Figures 24 & 25 display the Average UCS and Peak Load results for all tests conducted on the high density samples. Figure 24 outlines the initial tests conducted on soil with fibre and polymer additives separately, while Figure 25 covers the “optimum’ contents, with fibre and polymers admixtures applied together. Within Figure 24, a trend can be seen, with the 14 day curing time producing more strength (excluding 0.5% fibre), as this gives time for the sample to absorb all the water evenly, as well as bind to the admixture presented within the sample. Once it was obvious that the 14 day curing time was more promising with strength increases, the optimum trials were only conducted with 14 day curing times. Along with this, the optimum trials all contained 1.0% PVA. Figure 24 contains two polymer columns, both containing 1.0% PVA, as this was the best testing results out of the 5 PVA content trials, which is outlined within Table 11.

Series 1 2 3 4 5 6 7 8 9

Sample Mixture 00F10P01B162D17W14C 00F10P03B162D17W14C 00F10P05B162D17W14C 25F10P01B162D17W14C 25F10P03B162D17W14C 25F10P05B162D17W14C 50F10P01B162D17W14C 50F10P03B162D17W14C 50F10P05B162D17W14C

FIGURE 25 – Average Results – Optimum High Density Sample


40

Final Year Project Report From the graphed data in Figure 25, 0.5% BTCA was chosen as the most consistent trial of BTCA and will further be used as the “optimum” when comparing trials. A high density “optimum” sample refers to a sample containing 1.0% PVA, 0.5% BTCA, cured for 14 days, and contains a fibre content of 0, 0.25 or 0.5%. The data collected was then converted into an “Average Strength Increase”. Assessed through the comparison of the average UCS values obtained from the original high density clay samples alone. This has been tabulated within Table 12 below, and graphically represented in Figure 24 below.

Average UCS Strength Increase

Fibre

Clay

16.2 1 day 566.15 0.00%

14 days 623.46 10.12%

0.25% 1 day 14 days 795.8 813.7 40.56% 43.73%

0.50% 1 day 14 days 1002.2 825.57 77.02% 45.82%

Optimum polymer

Optimum Contents

1 1 day 534.7 -5.56%

14 days 709.9 25.39%

0% 697.4 23.18%

0.5% BTCA 0.25% 0.50% 770.7 734.66 36.13% 29.76%

TABLE 12 - Average UCS & Strength Increases for High Density Samples Series 1 2 3 4 5 6 7 8 9 10 11

Sample Mixture 00F00P00B162D17W01C 00F00P00B162D17W14C 25F00P00B162D17W01C 25F00P00B162D17W14C 50F00P00B162D17W01C 50F00P00B162D17W14C 00F10P00B162D17W01C 00F10P00B162D17W14C 00F10P05B162D17W14C 25F10P05B162D17W14C 50F10P05B162D17W14C

TABLE 13 – Outline of Sample Mixtures in Series The strength increase is calculated as a percentage increase from the UCS strength from the original soil sample cured for 1 day.

FIGURE 26 – Average Strength Gain for High Density Samples Matthew Ouston  S0158615  CQUniversity [email protected]

41

Final Year Project Report The above graphed data clearly demonstrates the trend that was discussed from the initial UCS data. The increase in curing time (Series 1 – Series 2) shows that the 14 days alone gave a gain of 10% in strength. However, the main increase came from the admixture of fibre within the expansive clay samples at a high density. The fibre was able to help aid the samples by binding within and applying the fibres natural tensile strength to aid in strength gain. 0.25% fibre added approximately 40% strength, while the 0.5% trials reached approximately 80%. It is clear that compared to the polymer samples; which increased by approximately 20% once given 14 days to cure and bind the sample together, that the fibre admixture was the optimum strength supplement. Further discussions will be made within the next section of this report, outlining further trends and recommendations.


42


4.3

LOW DENSITY

Table 14 on the following page contains all Triaxial testing that was covered for the low density samples, containing the UCS and Peak Load for each test, as well as factors such as the admixture content, curing time and dates, heights and moisture contents. The Peak Load was found during testing using the Triaxial Testing Machine, which allowed for all samples to have their UCS results calculated. As previously mentioned, outliers were eliminated from the “average UCS” calculation, allowing for consistent comparability of results.


43


10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10

11

12

13

14

15

16

20 1

20 - 2

20 - 3

21 - 1

21 - 2

21 - 3

22 - 1

22 - 2

10.8

10.8

9

22 - 3

Density (kN/m3)

Test No.

48

48

48

48

48

48

48

48

48

48

48

48

48

48

48

48

48


0.5

0.5

0.5

0.25

0.25

0.25

0

0

0

0

0

0.5

0.5

0.25

0.25

0

0

Fibre (%)

0

0.1 0.3 0.5 1 1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

5

3

1

5

3

1

5

3

1

0

0.1 0.3 0.5 1 1.5

1.5

0

0

0

0

0

0

14

14

14

14

14

14

14

14

14

14

1

14

1

14

1

14

1


0

0

0

0

0

0

PVA (%)

3

3

3

3

3

3

3

3

3

1

1

3

3

3

3

3

3


To-do

9/05/2016

27/04/2016

27/04/2016

18/04/2016

29/03/2016

6/04/2016

6/04/2016

18/04/2016

6/04/2016

21/03/2016

6/04/2016

29/03/2016

22/03/2016

Mix date

Complete

10/05/2016

28/04/2016

28/04/2016

19/04/2016

30/03/2016

7/04/2016

7/04/2016

19/04/2016

7/04/2016

22/03/2016

7/04/2016

30/03/2016

23/03/2016

Sample prep date

Curing

25/05/2016

13/05/2016

13/05/2016

4/05/2016

14/04/2016

8/04/2016

22/04/2016

20/04/2016

22/04/2016

23/03/2016

22/04/2016

14/04/2016

24/03/2016

Test date

103 103 103 104 104 104 104 103 104 104 104 102 103 103

102 101 101 101 102 101 101 102 101

103 103 103 102 103 102 101 101 101

103 103 103 104 104 103 102 103 103

102 101 101 101 102 101 101 102 100

103 103 103 102 103 102 101 101 101

104 100 103 103 103

104 103 102 103 104

103 100 102 103 104

104 104 103

104 105 105

104 105 105 104 104 103

100 101 103

102 102 102

102 102 102 103 102 103

104 103 107

101 101 101

101 101 101 104 102 109



TABLE 14 – Low Density Test Results

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

48.14 48.91 48.75 47.56 47.67 46.98 47.54 47.23 47.17

46.55 46.24 45.87 47.01 47.23 46.68 46.43 46.79 47.06

47.6 47.29 47.44 47.21 46.87 46.77 46.75 47.02 46.95

44.03 46.46 47.11 43.68 43.50

47.15 47.34 45.56 44.98 44.88

46.5 46.54 46.8

43.97 44.87 45.12

47.5 43.71 44.2

46.27 46.12

45.59 47.318

45.61 45.76 46.25


177.150 199.680 200.712 196.842 207.462 207.562 187.209 229.247 254.600

200.756 200.536 213.939 212.506 209.969 223.599 263.588 263.416 288.625

106.990 112.720 109.280 88.810 99.960 108.590 101.460 137.260 143.420

66.210 78.950 179.910 205.370 247.000

24.940 32.330 37.150 63.810 91.840

24.490 33.260 33.950

17.610 14.860 21.910

53.930 50.720 57.100

12.380 15.650

18.650 20.360

17.720 17.200 15.310

Load at Peak (N)

223.685

203.955

192.514

271.876

215.358

205.077

127.380

99.120

109.663

155.488

50.014

30.567

18.127

53.917

DATA CORRUPT

14.015

19.505

DATA CORRUPT

16.743


80.986 89.200 89.600 85.900 93.800 93.700 84.400 99.600 112.500

93.779 96.600 100.000 97.900 98.900 105.300 119.500 122.500 129.500

48.410 49.830 49.890 39.560 44.520 48.310 48.380 61.530 65.030

29.040 37.420 76.080 93.650 112.780

9.890 13.170 16.530 27.880 40.760

10.390 13.620 13.910

7.230 6.240 8.890

23.010 20.610 23.560

5.070 6.270

7.690 10.090

7.190 6.790 6.210

UCS

98.833

91.133

86.595

123.833

100.700

96.793

63.280

44.130

49.380

69.800

21.650

12.640

7.460

22.400

5.670

8.890

6.730

Average UCS (kPa)


44


Series 1 2 3 4 5 6 7 8

Sample Mixture 00F00P00B108D48W01C 00F00P00B108D48W14C 25F00P00B108D48W01C 25F00P00B108D48W14C 50F00P00B108D48W01C 50F00P00B108D48W14C 00F15P00B108D48W01C 00F15P00B108D48W14C

FIGURE 27 – Average Results – Low Density Samples Figures 27 & 28 display the Average UCS and Peak Load results for all tests conducted on the low density samples. Figure 27 outlines the initial tests conducted on soil with fibre and polymer additives separately, while Figure 28 covers the “optimum” contents, with fibre and polymers admixtures applied together. Within Figure 27, a trend can be seen, with the 14 day curing time producing more strength (every second column increases), as this gives time for the sample to absorb all the water evenly, as well as bind to the admixture presented within the sample. Once it was obvious that the 14 day curing time was more promising with strength increases, the optimum trials were only conducted with 14 day curing times. Along with this, the optimum trials all contained 1.5% PVA, as it was the greatest performing PVA trial. It is important to also note the huge increase in strength for PVA trials when left to cute for 14 days. The PVA solution is able to bind mineral particles with the soil grains much more effectively and allow the soil to avoid being broken down into smaller fragments or separating in shear. Figure 27 contains two polymer columns, both containing 1.5% PVA, as this was the best testing results out of the 5 PVA content trials, which is outlined within Table 11.

Series 1 2 3 4 5 6 7 8 9 10

Sample Mixture 00F00P00B108D48W01C 00F15P01B108D48W14C 00F15P03B108D48W14C 00F15P05B108D48W14C 25F15P01B108D48W14C 25F15P03B108D48W14C 25F15P05B108D48W14C 50F15P01B108D48W14C 50F15P03B108D48W14C 50F15P05B108D48W14C

FIGURE 28 – Average Results – Optimum Low Density Sample Matthew Ouston  S0158615  CQUniversity [email protected]

45

Final Year Project Report From the graphed data in Figure 28, 0.5% BTCA was chosen as the most consistent trial of BTCA and will further be used as the “optimum” when comparing trials. A low density “optimum” sample refers to a sample containing 1.5% PVA, 0.5% BTCA, cured for 14 days, and contains a fibre content of 0, 0.25 or 0.5%. The data collected was then converted into an “Average Strength Increase”. Assessed through the comparison of the average UCS values obtained from the original low density clay samples alone. This has been tabulated within Table 15 below, and graphically represented in Figure 29 below. Fibre

Clay 16.2 kPa Strength Increase

1 day 6.53 0.00%

14 days 9.08 39.05%

0.25% 1 day 14 days 5.79 23.53 -11.33% 260.34%

Optimum polymer

0.50% 1 1 day 14 days 1 day 14 days 7.78 12.87 44.1 116.6 19.14% 97.09% 575.34% 1685.60%

Optimum Contents 0.5% BTCA 0% 0.25% 0.50% 66.91 123.83 98.83 924.66% 1796.32% 1413.48%

TABLE 15 - Average UCS & Strength Increases for Low Density Samples Series 1 2 3 4 5 6 7 8 9 10 11

Sample Mixture 00F00P00B108D48W01C 00F00P00B108D48W14C 25F00P00B108D48W01C 25F00P00B108D48W14C 50F00P00B108D48W01C 50F00P00B108D48W14C 00F15P00B108D48W01C 00F15P00B108D48W14C 00F15P05B108D48W14C 25F15P05B108D48W14C 50F15P05B108D48W14C

TABLE 16 – Outline of Sample Mixtures in Series

FIGURE 29 – Average Strength Gain for Low Density Samples Matthew Ouston  S0158615  CQUniversity [email protected]

46

Final Year Project Report The above graphed data clearly demonstrates the trend that was discussed from the initial UCS data. The increase in curing time (Series 1 – Series 2) shows that the 14 days alone gave a gain of approximately 40% in strength. This is a 30% increase from the high density samples. This is most likely due to the large amount of additional water applied to the samples to reach 48%, meaning that when a small curing time is used, the water is not completely absorbed evenly throughout the sample, leaving weaker points within the specimen, causing it to not reach the same strength as a sample left to cure for 14 days. The main increase came from the admixture of polymer within the expansive clay samples at a low density. The fibre additive did have an increase of roughly 260% at 0.25%, however, when it is considered that the starting strength was a UCS value of 7, and the increase reached a total of 22, it can be seen that the increase is not significant enough to be applied to a foundation design. The PVA admixture on the other hand, aided the initial soil sample with an increase of up to 1700%, which raised the UCS value to 112 kPa. This is a much greater impact, as a foundation design can be created for a soil surface strength of upwards of 100 kPa. It is clear that compared to the fibre samples; which increased by approximately 260% once given 14 days to cure and bind the sample together, that the PVA admixture was the optimum strength supplement. Further discussions will be made within the next section of this report, outlining further trends and recommendations.


47


4.4

DISCUSSION

There were several factors that were researched within this project. The strength increase of the unconfined compressive strength was the main aspect considered, however, other deliberations were studied, such as the nature of the samples behaviour under failure load (ductile or brittle), the failure type for individual samples or densities, behaviour of samples when soaked, as well as costing.

4.4.1

UNCONFINED COMPRESSIVE STRENGTH

The UCS is the load per unit area (maximum axial compressive stress) where the cylindrical specimen of a cohesive soil fails in compression. This is the main area of focus for this project, and will be the basis of determining which admixture is deemed the most useful within the expansive clay soils. As seen in Tables 11 & 14, as well as included in Appendix K of this report, tests were completed on various samples with a number of admixtures, clay samples, fibre only, PVA only, as well as mixtures of these contents and BTCA for “optimal” trials. The initial tests with clay only allowed the strength increases of each additive to be measured to a base point. As two densities were used within testing to find how each additive aided or reacted with various types of reinforcement of stabilisers, the optimum results for both vary greatly. 4.4.1.1 High Density The high density samples compacted at 16.2 kN/m3 reacted best when left to cure for 14 days, as was demonstrated within the above results section. While overall, the dense samples responded best with the fibre reinforcement, displaying that the greater the fibre content, the higher the strength increase. This has been displayed, but is more evident within Figure 30, outlining the maximum UCS results from testing the high density samples.

FIGURE 30 – Comparison of Soil and Fibre Samples – High Density


48

Final Year Project Report Figure 30 not only displays the increase in strength from the initial clay sample to the fibre samples containing 0.25% and 0.5% fibre respectively; but also demonstrates the linear increase in fibre content is being matched by the increase in strength. It is assumed that there would be a point that the fibre content of the soil sample would begin to hinder the performance of the specimen and the strength would begin to decrease below the initial strength. However, for the needs of this project, it has been established that the highest fibre content of 0.5% produced the most effective strength increase.

FIGURE 31 – Soil Sample with 0.5% Fibre Additive While the graph shows the increase in strength as a linear gain, additional fibre could corrupt the sample through too much fibre comparatively to the soil. Figure 31 displays a sample at 0.5% fibre content. Looking at further testing with possible samples at 0.75% and 1.0% fibre would be challenging, as the fibres are difficult to mix within the soil sample, avoiding clumping and other issues. Within the results section, it was outlined that curing time for PVA was of utmost importance, as it allows the PVA to bind the course grain material of the clay together with the mineral particles, preventing the samples from separating in shear or failing. The dense samples when applied solely with PVA did not increase at the same rate of fibre reinforcement trials, as well as having no distinctive trend within testing, outlined within Figure 32. 1.0% PVA increased the strength by approximately 140 kPa and will be applied within FIGURE 32 – Comparison of Soil and PVA Samples – High Density optimum trials.


49

Final Year Project Report After trialling various curing times, fibre and PVA contents, the final step was to experiment with “Optimum” tests. These are a combination of optimum amounts of the above mentioned variables. Within the optimum trials, BTCA was added as a cross-linker to assist the PVA within the sample conditions. The BTCA was trialled at three different contents (0.1%, 0.3% & 0.5%), however, was not expected to make a large difference in strength, as it was mainly applied to help the PVA solve its problem of being water soluble. Within Table 11 of this report, the 9 tests carried out for optimum contents are listed, covering BTCA in three percentages, as well as Fibre contents of 0, 0.25 and 0.5%, along with the optimum curing time of 14 days, and PVA admixture of 1.0%. The results are displayed within Figure 33.

FIGURE 33 – Comparison of Soil and Optimum Samples – High Density Figure 34 displays that all optimal trials reached above 700kPa, increasing the original soil samples strength by between 150 – 200 kPa. These are promising increases in strength, however, as they are applying all admixtures within one sample, the increase does not justify the cost, as the fibre content of 0.5% outperforms the optimum contents with regard to strength increase. The best performing variables for the dense samples were the 14 day curing time, 0.5% fibre, 1.0% PVA, and 0.5% BTCA. It is clear from the above graphed data that to gain the greatest strength increase, the expansive clay soil at a dense capacity should be reinforced with fibre, at a content of 0.5%.


50

Final Year Project Report 4.4.1.2 Low Density The low density samples compacted at 10.8 kN/m3 reacted best when left to cure for 14 days, as was demonstrated within the above results section. This was of particular importance for the low density samples, as their moisture content was 48%, nearly half of the samples weight in water. The added curing time allows the samples clay to absorb the water thoroughly and evenly throughout the sample, giving the sample a stronger base to hold force, rather than be pressed down on itself. The curing however does not stop this fully, as the samples are at a low density with high moisture content, making them weak by nature. As displayed in Figure 35, the specimen will give as soon as pressured and continue to do so until reaching failure or the end of the testing time.

FIGURE 35 – Low Density Sample being Pressed Downwards It is clear that to create a stronger sample for the low density material, the soil had to be made stronger, as it did not hold a load properly without giving in and sinking down onto itself. Overall, the low density material did not increase greatly when additional fibre was added to the specimen, this is due to the wet material not reaching a failure point, therefore not applying the fibres natural tensile strength to hold together and withstand a load. Along with this problem, the fibres naturally were not binding with the loose material, meaning that when the sample did start to fail, the material would not hold onto the fibres, giving very little extra strength.

FIGURE 36 – Comparison of Soil and Fibre Samples – Low Density


51

Final Year Project Report Within Figure 36 above, it is very evident that a trend is occurring, as the three best performing samples with regard to strength were the three cured for 14 days, displaying the need for a longer curing time. Along with this, the tests also showed that the 0.25% fibre outperformed the 0.5% fibre. This is contradictory to the dense samples, where the fibre increase matched the strength increase. Further testing with optimum contents would prove to be necessary to find if this is consistent throughout the loose material, showing that there is a point where the fibre material starts to negatively affect the sample. The polymer trials were a huge success, as displayed earlier, there were increases of up to 115 kPa. Looking at these, it may seem insignificant, as this is smaller than the increases found from fibre within the dense samples. However, when it is taken into account that the initial clay sample at 10kN/m3 tested at 7 kPa, this means there was close to a 1700% increase in strength. Once again, the 14 day trials tested much better than the 1 day trials, as depicted within the graphed UCS data in Figure 37.

FIGURE 37 – Low Density Polymer Trials – Curing Time Comparison This strength increase was so great, but how did it occur? The PVA when applied to the wetter samples, absorbs the excess water of the sample. The difference can clearly be seen in Figure 38.

FIGURE 38 – Prepared PVA Sample vs Prepared Clay Sample Matthew Ouston  S0158615  CQUniversity [email protected]

52

Final Year Project Report This huge change in the preparation phase from the PVA then rolls onto the compaction stage, where the sample is a lot denser, containing less air-voids and more stability, without increasing or decreasing the water content of density of the sample, shown in Figure 39.

Clay Sample

Fibre Sample

PVA Sample

FIGURE 39 – Three Types of Low Density Samples This change is the change that was needed to create a strength increase within these samples, as the polymer has now forced these samples to take a load without giving in and squishing down onto itself. This, in turn, results in a large strength gain for each sample. From the tests conducted on the low density material, the next stage of testing was the “Optimum” tests. These are a combination of optimum amounts of the above tested variables. Within the optimum trials, BTCA was added as a cross-linker to assist the PVA within the sample conditions. The BTCA was trialled at three different contents (0.1%, 0.3% & 0.5%), however, was not expected to make a large difference in strength, as it was mainly applied to help the PVA solve its problem of being water soluble. Within Table 11 of this report, the 9 tests carried out for optimum contents are listed, covering BTCA in three percentages, as well as Fibre contents of 0, 0.25 and 0.5%, along with the optimum curing time of 14 days, and PVA admixture of 1.5%. The results are displayed within Figure 40.


53


FIGURE 40 – Comparison of Soil and Optimum Samples – Low Density The above graph concludes the initial findings from the fibre trials, that 0.25% fibre tested greater than the 0.5% fibre trials. This demonstrates that the optimum fibre content must be within 0.25% and 0.5% fibre content, as displayed within the graphed data labelled “Optimum Fibre Content”. The optimal trials however were successful, with the 0.25% fibre trial giving the best result out of all trials for low density. A total increase of roughly 1800%. From the testing stages above, the best performing variables for the low density samples were the 14 day curing time, 0.25% fibre, 1.5% PVA, and 0.5% BTCA. The results of the low density trials display that to obtain the greatest strength gain, in the expansive clay soils at a high moisture content, the optimum trial with 0.25% fibre is the best option, however, it is only a total of 5kPa stronger than the 1.5% polymer at 14 days on its own. The cost spent for the extra amount of fibre is not worth the small increase in strength.


54


4.4.2

NATURAL BEHAVIOURS UNDER FAILURE LOAD

Each soil type compacted at various densities and mixed at different moisture contents will act differently under a failure load. This is due to the soil samples containing different engineering properties, failing at different points, through various stages, and the soil reacting accordingly. A method of analysing the ductility of materials is to assess its strain at failure point. The strain for each point is gauged by dividing the axial deformation by the initial sample height. The maximum value for this is found as its maximum strain, however, if this is not reached within the first 15mm of axial displacement, the point at 15mm is taken as the “maximum strain”. Samples that contain high failure strain are classified as ductile failures. Ductile failure outlines the fact that the sample has the capacity to deform significantly prior to the loss of reaching the maximum bearing capacity. Samples that contain low failure strain are referred to as brittle, outlining that the soil sample is at risk of an abrupt loss of load capacity. A major trend can be observed when considering the failure strain of the separate density samples is displayed within Figure 41 and outlines the strain failure for all initial soil specimens (exhibited by the white circular points on each line) and their behaviour after this point.

FIGURE 41 – Stress vs Strain Comparison of Initial Clay Specimens As can be seen within Figure 41, the dense samples reached a much higher peak load, however, once the strain failure was achieved, the samples lost their ability to take a load capacity and dropped downward quickly. While the low density samples reached their failure strain much later in the test, while then continuing to take a similar stress while the strain increased. The trend indicates that the strain at failure for the high and low density samples is consistent throughout all soil only trials. This is a graphical representation of the difference in the brittle failure of the dense samples, and the ductility of the low density specimens.


55

Final Year Project Report The reasoning behind these behaviours can be explained, as the high density samples quickly take their maximum load capacity due to the samples not having the weak points to give in and take the stress applied, therefore becoming more and more deformed until the point of maximum stress is reached, where the sample fails in shear and does not have any load capacity left to take the stress applied. Contradictorily, the low density samples are full of voids, along with being at a very low density, meaning that as a load is applied to the sample, the sample gives in and begins to compress down on itself, becoming shorter in length, but not taking a maximum load. This causes the sample to continue to take a consistent load and fail in a ductile behaviour. However, the admixtures applied are able to change the natural behaviour of the samples, as displayed below in Figure 42, where the high density samples have been combined with fibre and the low density samples using polymer admixture.

FIGURE 42 – High Density Samples with Fibre – Low Density Samples with PVA While strength increases were the main point of this project, other results were also obtained, such as the natural behaviour of the soil samples being altered due to additives. The above graph has three lots of data within it. The graphed data in yellow – red represents the high density material. It can be seen that the initial soil sample reaches a strain failure and drops away due to brittle failure, however, once fibre is added, the two corresponding samples of 0.25% and 0.5% reach a failure strain and continue to hold a large load capacity for the continuation of the test. This is due to the fibre applying its natural tensile strength to stop the soil sample failing in shear. The samples are transformed from brittle to ductile because of the additional tensile strength the samples now possess.


56

Final Year Project Report Meanwhile, the low density samples are represented through 1 day (green) and 14 day (blue) trials. It can be seen that the initial first few trials with polymer still act in a ductile manner, however, once 0.5% - 1.0% is reached, the samples begin to develop a brittle type failure after the maximum strain is attained. The deduction from this is due to the polymer stopping the sample giving in when a load is applied, holding the specimen together to take a large load, however, then failing in shear as the PVA cannot hold the clay particles together once the maximum capacity is achieved. An alternative option to view the change in the natural behaviour of the soils failure is by investigation the amount of energy absorbed at the failure strain within various samples. The energy absorbed at failure has been assessed by calculating the area under the stress vs strain curves until the point of failure. The final result shows that samples having “absorbed” a large amount of energy before failure are deemed to signify ductile behaviour, meaning that samples with lower absorption before failure represent brittle behaviour. Figure 43 outlines the increase in energy absorption for the high density samples with increased fibre.

FIGURE 43 – Energy Absorbed before Failure – High Density Fibre Samples


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4.4.3

FAILURE TYPE

The failure type of each sample can be seen within most above graphed data, as the dense samples fail in a brittle state, whereas the low density samples act in a plastic manner and have ductile failure. Figure 44 displays the general failure of the dense samples. As the samples are compacted with one compaction, the soils density and moisture content is not consistent throughout the sample. If the samples were compacted in layers (5 is optimal), then a consistent density and moisture would be expected, as well as the failure point would be targeted in the middle of the samples, where the largest amount of stress is applied. It can be seen that the samples begin to crack at the base, with shards of soil peeling off from the sample, however, the majority of the sample is not deformed, this failure type may be classified as a brittle failure

FIGURE 44 – High Density Samples Failing – Brittle It is worth noting that the fibre reinforcement alters this failure by holding the sample together with its tensile strength, displayed in Figure 45, this is the reason for the samples with fibre additives to have a ductile failure rather than the brittle natural failure of the dense samples.

FIGURE 45 – Change from Brittle Failure to Ductile Failure – Fibre Reinforcement Matthew Ouston  S0158615  CQUniversity [email protected]

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Final Year Project Report Within the low density segment of the discussion (4.3.1.2), it was displayed in Figure 35 how the weak low density samples fail by simply pressing down on themselves, reaching the end of the testing process as a compressed deformed sample with no apparent shear failure, which indicates a highly plastic behaviour within the sample. When the low density samples do fail, it can be seen that they have deformed across the whole sample before one large crack occurs along the shear plane. This type of behaviour is representative of a ductile soil, with the soils failure classified as a shear plane failure, displayed in Figure 46 below.

FIGURE 46 – Low Density Samples – High Ductility – Shear Plane Failure However, once a high amount of PVA is added to the low density samples, the sample acts with less ductility due to fewer voids and the soil being bound together through the PVA solution, which therefore causes the samples to fail in a brittle format, displayed in Figure 47, where the specimen can be seen to be much more compact. The sample itself can still be seen to exhibit the natural failure in shear plane, however, is also much more brittle and falls apart easily once the maximum load have been applied.

FIGURE 47 – PVA Low Density Samples Failure


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4.4.4

SOAK TEST

A soak test was carried out on 6 samples (3 samples for each density). The samples were prepared and then set out as displayed in the Figure 48. Clay Only Samples

Optimum Samples

Clay & Fibre Samples

Low Density Samples

High Density Samples

FIGURE 48 – Layout of Soaked Samples Within minutes of the soil specimens being added to the water, the 4 samples without polymers started to lose particles.

FIGURE 49 - 5 Minutes into Soak Test It can be seen within Figure 50 that the high density soil sample began to dissipate, breaking down particles from the main soil specimen. After half an hour of the test, the high density soil sample had failed. This is known as “Slaking”, where a soil sample is broken down into smaller fragments on wetting. This is caused when clay swells and the trapped air bursts out. Interestingly, what can stop slaking from occurring is organic matter, as it binds the mineral particles, slowing the rate of wetting. This looks to be occurring within the fibre content sample of high density, as it had broken down much less than the clayonly sample. Matthew Ouston  S0158615  CQUniversity [email protected]

FIGURE 50 – 30 minutes into Soak Test

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Final Year Project Report Within Figure 51, it can be seen that the two low density samples (clay-only & fibre additive) were beginning to break down and slake after the hour mark and failed short of an hour and a half. By the end of the day all four samples not containing polymer had broken down and slaked, with evidence shown in the second photo of Figure 51. This is due to most soils in Australia being prone to slaking. Slaking is involved in the process of selfmulching, which occurs in many cracking clays. On the fourth day, the two optimum content samples were removed, however, the dense sample suffered a crack due to handling. Both samples were tested as displayed within Figure 52, showing how both samples lost significant strength, yet were still held together well due to the BTCA being applied as a cross-linker with the PVA. While Figure 53 outlines how the low density sample appeared before and after testing, with the in shear plane being very evident when the sample failed.

FIGURE 51 – Low Density Samples Slaking – Evidence of Slaking

FIGURE 52 – UCS Soak Test Results FIGURE 53 – Low Density Soak Sample Before and After Triaxial Test


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4.4.5

COSTING

The cost for each additive is listed within Table17 below:

Additive Fibre PVA BTCA

Cost

Units

25 264 925

$ / kg $ / kg $ / kg

TABLE 17 – Cost of Individual Additives The final section covered within this project was to obtain the costing required for certain admixtures within a soil foundation and compare them against other options, taking into account the effectiveness of the admixture option. To do this, a project description was set up, needing to reinforce an expansive clay soil for a 1 kilometre stretch of road, with a width of 8 meters and depth of 0.3m. The natural moisture content of the soil sits at 10%. Below are tables and graphs outlining variation types of effective processes and their costs calculated. Reinforcement of 1km of Road (8m width x 0.30m depth) - Low Density - High Moisture Content Volume Target unit weight Target Moisture content Natural Moisture content Dry soil mass water mass PVA BTCA Fibre Content Fibre Mass

2400 10.8 48 10 2592 984.96 14.7744 0.073872 0.25 6.48

m3 kN/m3 % % Tone initial soil mass for 1km Tone required to reach optimum moisture content Tonne 1.5% PVA (w/w with water mass) Tonne 0.5% BCTA (w/w with PVA mass) % chosen fibre reinforcement content Tonne 0.25% fibre (w/w with dry soil mass) COSTING OPTIONS

Option 1 - Fibre Additive Fibre Admixture Cost

$162,000.00

Cost for Fibre Reinforcement of Foundation for 1 km of road

Option 2 - Polymer Additive Polymer Blend (PVA & BTCA)

$3,968,773.20

Cost for Polymer Reinforcement of Foundation for 1 km of road

$4,130,773.20

Cost for Fibre & Polymer Reinforcement of Foundation for 1 km of road

Option 3 - Optimum Additive Fibre and Polymer Blend

TABLE 18 – Low Density / High Moisture Content – Foundation Options Table 18 summarises the viable options found within the testing phase of this project and calculates their approximate costing for the additives required. This costing was the plotted against the UCS of each option, exhibited in Figure 54.


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FIGURE 54 – UCS and Cost of Options – Low Density The graph shows that in relation to strength increase, the cost of the fibre additive into the low density foundation is greater than the polymer and optimum samples. However, the strength that the fibre adds is much less than the other two samples, and also is limited, as it was discovered through testing that the fibre has a limit between 0.25% and 0.5% where it begins to hinder the performance of the soil sample and begins to decrease in strength. The polymer samples (2 & 3), although more costly due to polymer being added to the water content, and the need for a large amount of water within the foundation, do provide a much larger strength increase, and as of yet, have not been found to have a point where additional additive over 1.5% will halt improvements to the soil strength.


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Final Year Project Report Reinforcement of 1km of Road (8m width x 0.30m depth) - High Density - Low Moisture Content Volume Target unit weight Target Moisture content Natural Moisture content Dry soil mass water mass Fibre Content Fibre Mass Fibre Content Fibre Mass PVA BTCA OPTION 1 Fibre Admixture Cost (0.25%) OPTION 2 Fibre Admixture Cost (0.5%) OPTION 3 Polymer Admixture Cost OPTION 4 Optimum Admixture Cost (0.5% Fibre)

2400 16.2 17 10 3888 272.16 0.25 9.72 0.5 19.44 2.7216 0.013608

m3 kN/m3 % % Tonne initial soil mass for 1km Tonne required to reach optimum moisture content % Tonne 0.25% fibre (w/w with dry soil mass) % Tonne 0.5% fibre (w/w with dry soil mass) Tonne 1.0% PVA (w/w with water mass) Tonne 0.5% BCTA (w/w with PVA mass) COSTING OPTIONS

$243,000.00


$486,000.00


$731,089.80


$1,217,089.80


TABLE 19 – High Density / Low Moisture Content – Foundation Options Table 19 gives costing estimates for additives used when a high density foundation is designed at lower moisture content, it takes into account both possible fibre contents, PVA & BTCA as a polymer mixture, as well as the optimal trial involving all additives at the superlative increments for strength increase. The costing can also be seen plotted against the UCS of each option, exhibited in Figure 55, outlining the strength increase against the cost increase.


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FIGURE 55 - UCS and Cost of Options – High Density The plotted graph above outlines the relationship between cost and strength increase for the greatest options produced from the testing stage of this project. It is clear that the fibre additives give the greatest increase at the lowest cost. The amount of fibre that would be required (0.25% 0.5%) would be dependent on the needs of the foundation strength for the particular project at hand, as well as the budget allocated to reinforcement of the foundation. Option 3 outlines the PVA and BTCA applied, presenting that there is a reasonable strength increase, however, in comparison to the cost of the fibres, it is most likely not as effective. The optimum sample gives a slightly better strength increase than the polymers alone, however, the price required to do this is much greater than the other options, making it not as economical of a choice. Along with this, it must be mentioned that the fibre increase in strength could be continued on with further testing of fibre such as 0.75% and 1.0%. Following the trend discovered within this project, it would be likely that the increase in fibre would be a linear trend in strength and costing, therefore allowing further to be spent to gain a greater strength increase, however, this is not confirmed.


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5.0 CONCLUSION Triaxial Testing was conducted on a variety of expansive clay samples, covering fibre, PVA and BTCA additives, with satisfactory results found within both density types. 14 day curing time was found to produce greater strength than the original 1 day curing period. For the higher density samples, it has been determined that the fibre additive produced the greater UCS results, increasing the strength from the original clay sample of 568kPa by approximately 77% to 977kPa with 0.5% fibre. This was near linear increase from the 0.25% which reached 976kPa, a 40% increase in strength. The polymer additives reached a maximum of 642kPa at 1.0% PVA after 14 days, a gain of 25% strength. When combined into optimal trials, the greatest value reached was 730.5kPa, using 0.5% fibre, 1.0% PVA and 0.5% BTCA. The UCS results show that 0.5% fibre surpassed all other trials in regards to strength and could be looked into being applied for real world studies against current techniques. Low density samples started at a very low point, containing a UCS of 7kPa. The use of fibres did increase the strength of the soil, with 0.25% displaying greater results (22.4kPa) than 0.5% (12.6kPa), which reveals that there is a certain point for the fibre additive where it begins to hinder performance within the expansive clay samples. However, the increase was inadequate due to the soil still being in a very weak state. Conversely to the fibre, PVA admixture showed very promising signs when combined with a 14 day curing period, allowing the PVA to bond with the soil particles, increasing the low density samples strength up to an impressive 113kPa, an increase in strength of not far from 1700%. Further trials were tested, ranging in optimum contents using 14 days curing time, 1.5% PVA and 0.5% BTCA, the paramount result was found to use 0.25% fibre and reached a UCS of 124kPa, a strength gain of approximately 1800%. Taking into account the starting strength of the soil sample, it can be deemed that both the 1.5% PVA trial and optimal content using 0.25% fibre would be suitable to apply as reinforcing agents. Although, when considering the extra additive amount of fibre that the optimal trial uses, the PVA content of 1.5% PVA would be most economical unless it was of utmost importance to gain the extra 10kPa obtained through the fibre reinforcement. When considering the natural failure of the samples and the changes made through admixtures applied, it was demonstrated how the fibre additive was able to alter the natural brittle nature of the dense samples and allow it to perform in a ductile state, caused by the added tensile strength of the fibres, clasping the soil particles together, resisting failure cracking, displayed through analysing the maximum stress/strain point, as well as plotting the energy absorbed at failure from underneath the plotted stress vs strain graph. Both assessments revealed the increase in ductility from the fibre additive. The additional polymer for both high and low density samples only decreased or changed nothing for the ductility, with the low density samples becoming much stronger, however, gaining a brittle behaviour of reaching failure and then fracturing. Overall, the results identified the brittle nature of the high density sample, and displayed that increased fibre contents are able to adapt the sample to perform with ductile behaviour. All optimum trials with fibre also acted ductile in failure, showing that a mix between polymers and fibres does not affect the fibre additive assisting the soils naturally low tensile strength. The addition of fibre would be recommended for soils needing increased ductility. The analysis of the type of failure that each sample developed matched well with the ductile or brittle failure of that sample. It was found that the dry samples had a brittle failure, while the wet samples performed plastically, deformed, failed in shear, creating a ductile failure. The fibres did hold the dry samples together, however this did not change the type of failure to a plane shear failure such as the wet samples. The polymer also dried up and bound the wet samples together, but the failure type, although changed to a brittle behaviour, was still an in plane shear.


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Final Year Project Report The soak test carried out allowed the assessment of BTCA to be conducted, with the optimal samples performing well, not slaking like the soil and fibre samples due to the BTCA coating the PVA contents within the specimen. This showed positive results and would recommend use of BTCA to bind the PVA solution into any soil specimen when rainfall or other water occurrences are possible. The costing of the various types of sample were covered, outlining the 2 best types of admixture for each density and allowing their increase in strength to be compared to their cost. It displayed that the best results when looking at it economically were fibre reinforcement at either percentage dependent on the strength increase needed for a high density foundation, while the low density foundation would be best effective with polymer reinforcement up to 1.5%. In conclusion, the assessment of UCS results, natural behaviour under the failure load, failure types, soaking ability and costing indicates that blends for the high density material containing fibre were most likely to be applied within industry practices, whereas low density material had a far superior reaction with PVA and would be the only consideration when looking to increase the strength of this foundation type. It is for this reason that the two types of reinforcement may be acknowledged as recommended reinforcement materials.


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6.0 RECOMMENDED FURTHER STUDIES The project studied provided successful results for both fibre and polymer reinforcement, and therefore there are hardly any recommendations that could be applied to improve the quality of results gained from this testing. Taking that into account, further testing for fibre and polymer contents that were not covered within this project could offer greater insight into potential “optimum” contents of each reinforcing agent:

 Conduct UCS testing on fibre contents above 0.5% for high density material, mmmm defining the point of hindrance for unconfined compressive strength increases  Conduct UCS testing on fibre contents between 0.25% and 0.5% on low density mmmm material, defining the point of hindrance for unconfined compressive strength mmmm increases  Assess maximum PVA content for strength increases on Low Density material mmmm through further UCS testing on blends above 1.5%  Assess strength increases of fibre and PVA blends against industry standards mmmm such as lime and cement  Evaluate most economic option (strength increase vs costing), comparing fibre mmmm and PVA to industry standard reinforcing agents


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7.0 REFERENCES 7.1

WORKS CITED

1) Ellaby, Les. 'The History Of Soil Stabilisation'. EzineArticles. N.p., 2015. Web. 12 Sep. 2015. 2) UTS researchers give unstable soils a carpeting. (n.d.). Retrieved December 11, 2016, http://newsroom.uts.edu.au/news/2014/11/uts-researchers-give-unstable-soils-carpeting. 3) Budhu, M., 2011. Soil Mechanics and Foundations. 3rd ed. s.l.:Wiley. 4) 4602.0.55.005 - Waste Account, Australia, Experimental Estimates, 2013. (n.d.). Retrieved October 15, 2015, http://www.abs.gov.au/ausstats/[email protected]/Latestproducts/4602.0.55.005Main Features42013 5) Mirzababaei, M., Miraftab, M., Mohamed, M., & Mcmahon, P. (2012). Impact of Carpet Waste Fibre Addition on Swelling Properties of Compacted Clays. Geotechnical and Geological Engineering Geotech Geol Eng, 173-182. 6) Syntechfibres.com,. 'Properties Of Polypropylene Fibres | Syntech Fibres'. N.p., 2015. Web. 16 Sep. 2015. 7) Uni, T., Ram, Y. J., Padu, K., Yachang, O., & Singh, H. (2014). Strength and Stiffness Response of Itanagar Soil Reinforced with Arecanut Fiber. International Journal of Innovative Research in Science, Engineering and Technology IJIRSET, 03(10), 16659-16667. doi:10.15680/ijirset.2014.0310034 8) The Many Uses of Fibers in Concrete Countertops. (n.d.). Retrieved March 12, 2016, http://www.concretecountertopinstitute.com/blog/2013/10/the-many-uses-of-fibers-inconcrete-countertops/ 9) Rafalko, S., Brandon, T., Filz, G., & Mitchell, J. (2007). Fiber Reinforcement for Rapid Stabilization of Soft Clay Soils. Transportation Research Record: Journal of the Transportation Research Board, 2026, 21-29. Retrieved September 12, 2015. 10) Li, J., Tang, C., Wang, D., Pei, X., & Shi, B. (2014). Effect of discrete fibre reinforcement on soil tensile strength. Journal of Rock Mechanics and Geotechnical Engineering, 6(2), 133-137. doi:10.1016/j.jrmge.2014.01.003 11) Explore scientific, technical, and medical research on ScienceDirect. (n.d.). Retrieved October 6, 2015, http://www.sciencedirect.com/ 12) Methods of testing soils for engineering purposes. Method 5.2.1, Soil compaction and density tests: Determination of the dry density/moisture content relation of a soil using modified compactive effort. (2003). Sydney, NSW: Standards Australia International. 13) Methods of testing soils for engineering purposes. determination of the cone liquid limit of a soil. (2003). Sydney, N.S.W.: Standards Australia. 14) Australian Standards – AS114.51 – 1996 “Methods for Sampling and Testing Aggregates – Uncofined Compressive Strength of Compacted Materials”. 15) Ding, B., Kim, H., Lee, S., Shao, C., Lee, D., Park, S., . . . Choi, K. (2002). Preparation and characterization of a nanoscale poly(vinyl alcohol) fiber aggregate produced by an electrospinning method. J. Polym. Sci. B Polym. Phys. Journal of Polymer Science Part B: Polymer Physics, 40(13), 1261-1268. Retrieved January 17, 2016. 16) What Exactly Is a Polymer? (n.d.). Retrieved December 29, 2015, http://composite.about.com/od/whatsacomposite/a/What-Is-A-Polymer.htm 17) Perry Chemical Corp - Home - Polyvinyl Alcohol, PVA, PVOH. (n.d.). Retrieved March 09, 2016, http://www.perrychem.com/ 18) Polyvinyl alcohol (PVA). (n.d.). Retrieved March 09, 2016, http://www.britannica.com/science/polyvinyl-alcohol Matthew Ouston  S0158615  CQUniversity [email protected]

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Final Year Project Report 19) Xu, G.C.,Yang,C.Q.,Deng,Y.,2001.Effects of Poly(vinylAlcohol) on the Strength of Kraft Paper Crosslinked by a Polycarboxylic Acid. J.PulpPap.Sci. 27 (1),14–17. 20) Awada, H., Bouatmane, M., & Daneault, C. (2015). High strength paper production based on esterification of thermomechanical pulp fibers in the presence of poly(vinyl alcohol). Heliyon, 1(3). Retrieved February 8, 2016. 21) Hejazi, S., Sheikhzadeh, M., Abtahi, S., & Zadhoush, A. (n.d.). A simple review of soil reinforcement by using natural and synthetic fibers. Construction and Building Materials, 100-116. 22) Tumsavas, Zeynal., Tumsavas, Fatma. (2011). The effect of polyvinyl alcohol (PVA) application on runoff, soil loss and drainage water under simulated rainfall conditions, Journal of Food, Agriculture & Environment (Volume 9), 757-762. Retrieved March 10, 2016. 23) Australian Standards – AS1289.1.1 - 2001 “Methods of testing soils for engineering purposes - Soil compaction and density tests – Preperation of Soil Sample” 24) Australian Standards – AS 1289.2 – 2005 “Methods of testing soils for engineering purposes Soil moisture content tests - Determination of the moisture content of a soil” 25) Australian Standards – AS 1289.5.2.1 – 2003 “Methods of testing soils for engineering purposes - Soil compaction and density tests - Determination of the dry density/moisture content relation of a soil using modified compactive effort” 26) Australian Standards – AS 1289.3.9.1 – 2002 “Methods of testing soils for engineering purposes - Soil classification tests— Determination of the cone liquid limit of a soil” 27) Çay, A., & Miraftab, M. (2013). Properties of electrospun poly(vinyl alcohol) hydrogel nanofibers crosslinked with 1,2,3,4-butanetetracarboxylic acid. Journal of Applied Polymer Science J. Appl. Polym. Sci., 129(6), 3140-3149. doi:10.1002/app.39036 28) Australian Standards – AS 1141.51 – 1996 “Methods for sampling and testing aggregates Unconfined compressive strength of compacted materials”


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7.2  



 

 



   

  



KNOWLEDGE BASED RESOURCES

Mirzababaei, M., Al-Rawas, A., & Yasrobi, S. (2009). Effect of polymers on swelling potential of expansive soils. Proceedings of the ICE - Ground Improvement, 111-119. Mirzababaei, M., Miraftab, M., Mohamed, M., & Mcmahon, P. (n.d.). Unconfined Compression Strength of Reinforced Clays with Carpet Waste Fibers. J. Geotech. Geoenviron. Eng. Journal of Geotechnical and Geoenvironmental Engineering, 483-493. Rafalko, S., Brandon, T., Filz, G., & Mitchell, J. (n.d.). Fiber Reinforcement for Rapid Stabilization of Soft Clay Soils. Transportation Research Record: Journal of the Transportation Research Board, 21-29. Sciencedirect.com,. 'Effect Of Discrete Fibre Reinforcement On Soil Tensile Strength'. N.p., 2015. Web. 15 Sep. 2015. The Many Uses of Fibers in Concrete Countertops. (n.d.). Retrieved August 4, 2015, http://www.concretecountertopinstitute.com/blog/2013/10/the-many-uses-of-fibers-inconcrete-countertops/ Boominathan A, Hari S. Liquefaction strength of fly ash reinforced with randomly distributed fibers. Soil Dyn Earthq Eng 2002;22:1027–33. 1,2,3,4 Butanetetracarboxylic Acid. (n.d.). Retrieved September 14, 2015. http://www.sigmaaldrich.com/catalog/search?term=1703-588&interface=CAS%20No.&N=0&mode=partialmax&lang=en®ion=AU&focus=product Polyvinyl Alcohol. (n.d.). Retrieved September 13, 2015. http://www.sigmaaldrich.com/catalog/search?term=9002-895&interface=CAS%20No.&N=0+&mode=partialmax&lang=en®ion=AU&focus=product Yetimoglu T, Inanir M, Inanir E. A study on bearing capacity of randomly distributed fiberreinforced sand fills overlying soft clay. Geotext Geomembr 2005;23:174–83. Diambra A, Ibraim E, Wood M, Russell A. Fiber reinforced sands: experiments and modeling. Geotext Geomembr 2010;28:238–50. Consoli C, Vendruscolo A, Fonini A, Rosa D. Fiber reinforcement effects on sand considering a wide cementation range. Geotext Geomembr 2009;27:196–203. Grogan P, Johnson G. Stabilization of high plasticity clay and silty sand by inclusion of discrete fibrillated polypropylene fibers for use in pavement subgrades. Technical report CPAR-GL-94-2. US Army Engineer Waterways Experiment Station, Vicksburg. UNCONFINED COMPRESSIVE STRENGTH OF COHESIVE SOIL. (2010, September 22). Retrieved September 5, 2015. Material Safety Data Sheet - Polyvinyl Alcohol MSDS. (n.d.). Retrieved October 12, 2015. http://www.sciencelab.com/msds.php?msdsId=9927396 Material Safety Data Sheet - 1,2,3,4-Butanetetracarboxylic acid. (n.d.). Retrieved September 19, 2015. http://datasheets.scbt.com/sc-251564.pdf Li C. Mechanical response of fiber-reinforced soil, PhD thesis, Faculty of the Graduate School of the University of Texas at Austin; 2005.


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8.0 APPENDICES

TABLE OF APPENDICES Appendix A:

Stage One Competency Reflective Paper

Appendix B:

Technical Poster

Appendix C:

Master Fiber 11

Appendix D:

MSDS Polyvinyl Alcohol

Appendix E:

MSDS Butanetetracarboxylic Acid

Appendix F:

Soil Preparation

Appendix G:

Compaction Data

Appendix H:

Atterberg Limit Testing

Appendix I:

Sample Preparation Spreadsheet

Appendix J:

Test Results

Appendix K:

Initial Soil Trials

Appendix L:

Risk Assessment – Testing

Appendix M:

Plant & Equipment Risk Assessment

Appendix N:

CQU Resources Agreement


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APPENDIX A - Stage One Competency Reflective Paper This paper displays my thought processes, learning’s and reflections made throughout the implementation stage of my undergraduate thesis project. Within the implementation process of my thesis, I have continually developed and improved my professional communication skills, both in verbal and written forms. My verbal communication skills have advanced throughout the term due to the meetings and phone calls held with my academic supervisor and experts in the field. This is due to the need for me to clearly articulate the questions and issues I have, along with the outputted data from my testing and my thoughts behind the results, allowing me to seek feedback or assistance to support the progression of my project. Through the large amount of research I have had to complete, including reading journal articles, analysing previous results, and therefore evolving new testing measures to help aid in the discussion of my thesis report; my written communication skills have continually developed. Along with general professional communication, I have further improved my understanding of engineering communication. I believe it is of the utmost importance that an engineer be able to sufficiently communicate their methods, solutions, findings and even problems within a project to any audience, while maintaining a degree of knowledge and effectiveness. My thesis project involved multiple stages of testing and examination, with all including various types of reinforcement techniques and other variables. Therefore it has been vital that I am able to display and professionally convey my findings throughout the several means necessary (report, poster, oral presentation, technical paper), which needs to considering the various medians of people I will be presenting these documents to, while also containing enough technical aspects to be vindicated with necessary detail. As I was working while conducting the bulk of my testing for my thesis, along with my academic supervisor having a busy schedule, my problem solving abilities were put to the test while looking to overcome issues prior, during and post testing. I believe that having to work through problems such as mixability of the sample, or outlying results have allowed my problem solving skills to grow and advance. My academic supervisor was always contactable when needed; however, I aimed at only pursuing support for critical points of my project, such as the start of a new stage of testing. This was evident when I had minor issues, as I would attempt to find a solution to the problem myself, which in turn, allows me to gain new knowledge and understanding of the task at hand. I believe that my project submissions depict the fact that I worked independently and solved problems when needed to be able to present a professional final thesis report and other documents at a high standard with specific knowledge across the area I covered. Throughout the planning stage of my thesis, I developed a Gantt chart to outline the amount of testing I required for my project and when I would be able to complete this by. Once finishing the planning stage, I had the testing outlined to be finalised by late November, which would then allow me to adjust some tests in the implementation stage if need be and make sure all results were perfected. However, due to the fact that I picked up a job over the third term and have carried that into the implementation stage of my project, I needed to readjust my testing schedule and was faced with the fact that my project scope comprised of a large amount of time consuming tests that would not be able to be completed during the twelve week term of 2016. This forced me to adjust my Gantt chart and evaluate the amount of testing that I needed to complete for my project, compared to the amount I had outlined initially. The adjustments I made allowed me to complete my testing within time and therefore, deliver a more competent report. This experience taught me how important tolerances are within any project, and how small and unexpected changes can create huge variations within the final outcome of the project. Matthew Ouston  S0158615  CQUniversity [email protected]

73

Final Year Project Report This project was the largest project I had worked on independently, and therefore, I had issues with scheduling and planning, such as adjusting my Gantt chart to take in the fact of unplanned changes or problems during testing. I also underestimated how long preparation for some tests would take, and had not allowed enough time for completion of these steps. My inexperience saw me needing to constantly adjust my plan for my implementation. However, I believe that if I was to undertake a large project like this again, I would have the improved skills from this thesis to allow me to have a greater understanding for timing and planning schedules. Along with this, I know that as I progress as a graduate engineer, I will be able to continually improve my technical planning skills and gain a greater understanding of this for larger, more involved topics and projects. Sustainability has been a large subject during my university degree and has been considered within all of the theoretical projects conducted. Therefore, once I started planning my thesis, I naturally included sustainability into the decision making process. While researching reinforcement elements to consider conducting testing with, I discovered fibre material. Fibre material has started to be further researched and tested within geotechnical engineering due to the fact that waste fibre is able to be applied as a reinforcing agent; which aids in reuse of discarded material and therefore is a sustainable option when considering soil and cement reinforcement. Through the completion of my thesis, I now understand sustainability through planning and design stages, as well as an implementation stage. I covered sustainability through several factors; such as economically; fibre pricing was compared to other elements such as fly ash, lime, and steel. The environmental impact was mentioned, stating the need for further studies to look at how fibre reacts within real world applications and if it spreads from the soils, creating waste, etc. I believe that researching and considering the sustainability performance of my project across all areas has allowed me to develop my knowledge in sustainability applied within engineering projects, and how important it is becoming within the modern world to have an even distribution of environmental, social and economic aspects. Through my thesis implementation project, I have been able to successfully develop technical competency is the Geotechnical industry of Civil Engineering. This is due to the feedback concerning the research, data and discussion’s I had included within my report that my academic supervisor was able to give me, which allowed me to further understand the topic more clearly and alter the necessary sections to complete the project. The final term of thesis work I conducted also saw me provide draft reports and other media’s to my academic supervisor for correct structuring and outlining of the project, which enriched my general knowledge and aiding in reaching my goal of completing each learning outcome. Overall, from conducting my thesis project; including the research, testing and analyses within the project; while also working alongside my academic supervisor, I believe I have improved my technical skills and knowledge within geotechnical engineering and engineering as a whole to a greater level, while also meeting the necessary learning outcomes of this course as well as Engineering Australia Competencies. My final year thesis project has given me all the tools to improve my knowledge in a number of areas, ranging in specific engineering knowledge, professional communication techniques, understanding sustainability and how it is applied within project decision making, along with planning and schedules for completion of a project. All of these skills and more that I have gained throughout this project and my degree as a whole will put me in good stead as begin work as a graduate civil engineer.


74


APPENDIX B – Technical Poster


75


APPENDIX C – Master Fiber 11


76


APPENDIX D – MSDS Polyvinyl Alcohol


77



78



79



80



81


APPENDIX E – MSDS Butanetetracarboxylic Acid


82



83



84



85



86



87



88


APPENDIX F – Soil Preparation TABLE 20 – Total Mass of Soil Sample Bucket No.

Total Weight (kg)

Mass of Soil (kg)

1 2 3 4 5 6 7 8

21.07 14.284 18.866 11.464 20.163 19.144 18.65 17.909

20.237 13.451 18.033 10.631 19.33 18.311 17.817 17.076

Total Mass of Soil =

134.886

TABLE 21 – Moisture Contents Samples – Week 6 Bucket No.

Tray No.

1 2 3 4 5 6 7 8

58 1 2 135 21 223 25 125

Paul

56

Weight of Wet Soil + Tray (g) 131.932 121.607 117.688 122.807 118.647 121.446 129.281 108.052 115.034

Weight of Dry Soil + Tray (g) 128.365 118.998 114.584 120.148 115.07 117.522 126.637 106.011 107.941

Tray Weight (g)

Mass of Wet Soil (g)

Mass of Dry Soil (g)


35.644 36.145 31.11 38.11 44.455 35.55 43.883 39.14

96.288 85.462 86.578 84.697 74.192 85.896 85.398 68.912

92.721 82.853 83.474 82.038 70.615 81.972 82.754 66.871

3.84702495 3.14895055 3.71852313 3.24118092 5.065496 4.78700044 3.19501172 3.05214518

Average =

3.7569166 9.84646566

35.905

79.129

Tray Weight (g) 40.126 43.826 35.654 35.253 38.422 38.885 36.376

Mass of Wet Soil (g) 56.773 64.946 51.604 62.559 79.385 65.92 78.573

72.036

TABLE 22 – Moisture Content Samples – Week 8 Bucket No.

Tray No.

1 2 4 5 6 7 8

7 26 227 245 108 105 228

Weight of Wet Soil + Tray (g) 96.899 108.772 87.258 97.812 117.807 104.805 114.949

Weight of Dry Soil + Tray (g) 95.986 107.976 86.456 95.961 115.595 103.893 113.08


Mass of Dry Soil (g) 55.86 64.15 50.802 60.708 77.173 65.008 76.704

Moisture Content (%) 1.634443251 1.240841777 1.578678005 3.049021546 2.866287432 1.402904258 2.436639549

89

Final Year Project Report Average =

2.029830831

TABLE 23 – Bulk & Dry Density of Soil Moisture Content

Test No.

Mass of Mould + Soil (g)

Mass of Soil (g)

10% 18% 25% 30% 35% 45% 50%

7 1 2 3 4 5 6

6866.1 7048.7 7071.7 7008.7 6902.4 6813 6748

1752.5 1935.1 1958.1 1895.1 1788.8 1699.4 1634.4

Bulk Density of Soil Dry Density of Soil 1.752 1.935 1.958 1.895 1.789 1.699 1.634

1.607 1.657 1.574 1.469 1.332 1.186 1.102

TABLE 24 – Moisture Compaction Data

Moisture Content 10% 18% 25% 30% 35% 45% 50%

Moisture Test Container No. No. 7 1 2 3 4 5 6

4c 4b MM2 MM3 4A B3 8

Mass of Moisture Container (g) 504.5 504.5 347.4 267.3 483.7 511.7 520.8

Mass of Moisture Container + Wet Soil (g) 2245.6 2436.5 2295.5 2102.4 2215.8 2126.4 2050.9

Mass of Moisture Container + Dry Soil (g) 2100.75 2158.8 1913.9 1690.3 1773.4 1638.8 1552.2

Moisture Content (%) 0.091 0.168 0.244 0.290 0.343 0.433 0.484

TABLE 25 – Dry Unit Weight Test No.

Mass of Mould + Soil (g)

Mass of Soil (kg)

Bulk Density of Soil (kg/m3)

Bulk Unit Weight of Soil (kN/m3)


Dry Unit Weight of Soil (kN/m3)

7 1 2 3 4 5 6

6866.100 7048.700 7071.700 7008.700 6902.400 6813.000 6748.000

1.753 1.935 1.958 1.895 1.789 1.699 1.634

1752.325 1934.907 1957.904 1894.911 1788.621 1699.230 1634.237

17.863 19.724 19.958 19.316 18.233 17.321 16.659

9.074 16.787 24.360 28.960 34.303 43.261 48.352

16.377 16.889 16.049 14.978 13.576 12.091 11.229


90


APPENDIX G – Compaction Data FIGURE 56 – Dry Density Results for Sarina Soil Sample

FIGURE 57 – Dry Unit Weight for Sarina Soil Sample


91


APPENDIX H – Atterberg Limit Testing TABLE 26 – Penetration Readings

Test No. 1 2 3 4 5 6

Penetration Readings Cone Penetration (mm) 1st 2nd Average 15.52 15.57 15.545 22.74 21.47 22.105 22.49 22.02 22.255 23.75 24.16 23.955 19.5 20.5 20 18.28 17.9 18.09

TABLE 27 – Penetration & Moisture Content Data Penetration & Moisture Content Data Test Number Average penetration (mm) Moisture Cup Number Moisture cup mass: m1 (g) Mass of wet soil + cup: m2 (g) Mass of dry soil + cup: m3 (g) Moisture Content (%)

1 15.545 2 31.079 37.225 34.8 0.652

2 22.105 56 35.81 48.731 43.991 0.579

3 22.255 58 35.583

0.000

4 23.955 60 43.767 57.979 52.601 0.609

5 20 64 38.653 45.724 43.106 0.588

6 18.09 112 37.742 56.602 49.684 0.579

TABLE 28 – Plastic Limit Data Moisture Content Data Test Number 1 2 75 106 Moisture cup number 38.274 38.573 Moisture cup mass: m1 (g) Mass of wet soil + cup: m2 (g) 46.026 43.56 Mass of dry soil + cup: m3 (g) 44.303 42.555 0.286 0.252 Moisture Contents (%) AVERAGE MOISTURE CONTENT = .269


92

mm

50 0.0002356

Compaction mould Diameter >>>>>>>>>>>>>>>>>>>>>>

Compaction mould volume (30mm heigh only)

1

1 8/04/2016 7/04/2016 6/04/2016

383.9

119.8

263.4

1.83

258.6

0.0

0.8

0.00

259.4

48

10.8

0

1 1 8/04/2016 7/04/2016 6/04/2016

383.9

119.8

263.9

1.83

259.1

0.3

0

2 extra samples - 14 day

Trial sample - 1 day


3

4

5

10

Matthew Ouston  S0158615  CQUniversity [email protected] 1 1 1 1 1 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3

1

1 1 1 1 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14

8/04/2016 8/04/2016 8/04/2016 8/04/2016 8/04/2016 4/05/2016 4/05/2016 4/05/2016 4/05/2016 4/05/2016 4/05/2016 4/05/2016 13/05/2016 13/05/2016 13/05/2016 13/05/2016 13/05/2016 13/05/2016 19/05/2016 19/05/2016 19/05/2016

7/04/2016 7/04/2016 7/04/2016 7/04/2016 7/04/2016 19/04/2016 19/04/2016 19/04/2016 19/04/2016 19/04/2016 19/04/2016 19/04/2016 28/04/2016 28/04/2016 28/04/2016 28/04/2016 28/04/2016 28/04/2016 4/05/2016 4/05/2016 4/05/2016

6/04/2016 6/04/2016 6/04/2016 6/04/2016 6/04/2016 18/04/2016 18/04/2016 18/04/2016 18/04/2016 18/04/2016 18/04/2016 18/04/2016 27/04/2016 27/04/2016 27/04/2016 27/04/2016 27/04/2016 27/04/2016 3/05/2016 3/05/2016 3/05/2016

383.8 455.2 455.2 383.9 383.9 383.9 383.9 383.9 383.9 455.2 455.2 455.2 455.2 455.2 455.2 383.9 383.9 383.9 455.2 455.2 455.2

119.8 59.0 59.0 119.8 119.8 121.7 121.7 121.7 121.7 61.9 61.9 61.9 61.9 61.9 61.9 121.7 121.7 121.7 61.9 61.9 61.9

260.2 395.2 394.2 263.5 262.8 262.3 262.3 262.3 260.9 393.4 393.4 393.4 392.4 392.4 392.4 261.6 261.6 261.6 391.4 391.4 391.4

1.83 1.83 1.83 1.83 1.83 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10

255.5 388.1 387.2 258.7 258.1 259.4 259.4 259.4 258.1 389.1 389.1 389.1 388.1 388.1 388.1 258.7 258.7 258.7 387.2 387.2 387.2

0.0 0.0 0.0 0.0 0.0 0.007 0.022 0.036 0.000 0.002 0.005 0.009 0.002 0.005 0.009 0.007 0.022 0.036 0.002 0.005 0.009

3.9 0.0 0.0 0.0 0.0 0.720 0.720 0.720 0.000 0.170 0.170 0.170 0.170 0.170 0.170 0.720 0.720 0.720 0.170 0.170 0.170

0.00 0.97 1.95 0.65 1.30 0.00 0.00 0.00 1.30 0.00 0.00 0.00 0.97 0.97 0.97 0.65 0.65 0.65 1.95 1.95 1.95

259.4 389.1 389.1 259.4 259.4 259.4 259.4 259.4 259.4 389.1 389.1 389.1 389.1 389.1 389.1 259.4 259.4 259.4 389.1 389.1 389.1

48 17 17 48 48 48 48 48 48 17 17 17 17 17 17 48 48 48 17 17 17

10.8 16.2 16.2 10.8 10.8 10.8 10.8 10.8 10.8 16.2 16.2 16.2 16.2 16.2 16.2 10.8 10.8 10.8 16.2 16.2 16.2

0 0 0 0 0 1 3 5 0 1 3 5 1 3 5 1 3 5 1 3 5

1.5

0

0

0

0

1.5 1.5 1.5

0

1 1 1

1 1 1

1.5 1.5 1.5

1 1 1

0

0.25

0.5

0.25

0.5

0 0 0

0.5

0 0 0

0.25 0.25 0.25

0.25 0.25 0.25

0.5 0.5 0.5


3 samples - 14 days

3 samples - 14 days

3 samples - 14 days

3 samples - 14 days

3 samples - 14 days 3 samples - 14 days 3 samples - 14 days

3 samples - 1 day





8

9

10

11

12

13 14 15

15

1 2 3

1 2 3

1 2 3

1 2 3

6

12

14

20

13

17

18

21

19

TABLE 29 – Sample Preparation Spreadsheet

1 1 8/04/2016 7/04/2016 6/04/2016 383.9

119.8

261.5

1.83

256.8

0.0

2.6

0.00

259.4

48

10.8

0

1

0


7

4

1 1 8/04/2016 7/04/2016 6/04/2016 383.9

119.8

262.8

1.83

258.1

0.0

1.3

0.00

259.4

48

10.8

0

0.5

0


6

15

3 14 22/04/2016 7/04/2016

6/04/2016

383.9

119.8

264.1

1.83

259.4

0.0

0.3

0.00

259.4

48

10.8

0

0.0

0.0

0.00

259.4

48

10.8

0

0

0.1

0

3 7/04/2016

6/04/2016

455.2

59.0

396.2

0

3 1 14

8/04/2016 22/04/2016

7/04/2016

6/04/2016

455.2

59.0

396.2

1.83

0.0

0.0

0.00

389.1

17

16.2

0

1.83

Repeat

389.1

Curing

389.1

0.0

0.0

0.00

389.1

17

16.2

0

0

0

2

2

Test Date

Compaction Date

Mixture Date

Total mass (gr)

Water mass (gr)

catch up

initial moist soil (gr)

0

0

3 samples - 1 day cure

2 extra samples - 14 day

1

1

(%)

to-do completed

intial water content (%)

Dry Soil BTCA mass (gr) mass (gr)

PVA (gr)

Fibre mass (gr)

Dry Mass (gram) (Ms+Mf+Madd1+ Madd2)

Water content (%)

PVA %

Dry Unit Weight(kN/m3)

Description

No.

Test No.

Fibre Content BTCA %

m3

mm

120

Compaction Height >>>>>>>>>>>>>>>>>>>>>>>>>>>>>

m/s2

9.81

gravity >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Preparation of sample for swelling pressure test in the compaction mould

Test Spesimens Preparation


APPENDIX I – Sample Preparation Spreadsheet

93

Density (kN/m3)

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

16.2

Test No.

1

2

3

4

5

6

7


8

17 - 1

17 - 2

17 - 3

18 - 1

18 - 2

18 - 3

19 - 1

19 - 2

19 - 3

17

17

17

17

17

17

17

17

17

17

17

17

17

17

17

17

17


0.5

0.5

0.5

0.25

0.25

0.25

0

0

0

0

0

0.5

0.5

0.25

0.25

0

0

Fibre (%)

0

0.1 0.3 0.5 1 1.5

1

1

1

1

1

1

1

1

5

3

1

5

3

1

5

3

1

0

0.1 0.3 0.5 1 1.5

1

0

0

0

0

0

0

14

14

14

14

14

14

14

14

14

14

1

14

1

14

1

14

1


0

0

0

0

0

0

PVA (%)

3

3

3

3

3

3

3

3

3

1

1

3

3

3

3

3

3


To-do

3/05/2016

27/04/2016

26/04/2016

29/03/2016

21/03/2016

6/04/2016

8/03/2016

6/04/2016

6/04/2016

4/05/2016

28/04/2016

27/04/2016

30/03/2016

22/03/2016

7/04/2016

9/03/2016

7/04/2016

7/04/2016

7/04/2016

30/03/2016

29/03/2016 6/04/2016

7/04/2016

Sample prep date

Curing

6/04/2016

Mix date

Complete

19/05/2016

13/04/2016

12/04/2016

14/04/2016

23/03/2016

22/04/2016

10/03/2016

22/04/2016

8/04/2016

22/04/2016

14/04/2016

8/04/2016

Test date

TABLE 30 – High Density Tests & Results

103 104 104 103 104 104 103 103 103 104

104 104 104 103 104 104 103 104 103 103

103 103 103 103 103 102 102 103 102 103 104 102 102 105

103 104 105 102 103 102 104 102 104

102 103 103 104 104 103 103 102 103

102 103 103 103 103 101 102 104 101 102 104 102 104 105

103 104 105 102 103 102 104 102 104

102 103 103 104 104 103 103 102 103

103 103 103 102 103

104 103 103

104 103 103

103 104 102 103 103

104 102 103

104 103 103

104 103 103 103 102 102



49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

17.62 15.98 16.35 16.38 16.61 16.22 17.15 17.20 17.14

17.22 16.56 17.81 17.31 16.55 16.49 16.56 17.01 17.12

17.15 17.36 18.10 17.21 16.93 17.55 16.38 17.12 16.21

17.52 16.41 17.29 16.28 18.98

17.21 16.93 17.55 16.38 17.12

16.99 16.46 17.40

16.10 16.69 16.88 16.82

16.93 17.55 17.56

15.67 17.25 16.60

17.93 16.80 16.90

17.00 17.32 16.49


1728.756 1881.498 1535.970 1310.205 1417.812 1442.077 1676.814 1619.255 1745.797

1735.796 1817.418 1518.577 1872.854 1640.309 1610.995 1735.119 1652.191 1727.895

1345.852 1217.031 1141.871 1435.115 1340.422 1431.417 1306.278 1254.766 1160.927

1059.850 1364.851 1398.290 1433.220 1167.520

1107.440 1165.230 985.847 1068.400 1001.200

2051.150 2057.600 1733.600

2074.030 1460.540 1635.970 2065.161

1725.470 1815.550 1562.670

1463.807 1659.187 1740.367

1279.210 1223.950 1253.880

1336.500 1063.760 1135.820

Load at Peak (N)

1680.622

1390.031

1715.408

1705.068

1708.053

1690.597

1240.657

1402.318

1234.918

1284.746

1065.623

1947.450

2069.596

1701.230

1621.120

1252.347

1178.693


716.081 780.351 661.521 618.517 657.660 664.797 724.210 731.850 747.930

711.553 804.002 658.462 762.013 658.759 721.984 713.834 727.594 750.064

610.906 555.719 525.309 644.430 609.506 654.165 603.495 567.775 523.796

466.110 621.820 631.570 642.660 514.950

507.149 517.573 442.798 486.689 440.421

1003.020 993.320 833.960

873.190 621.900 699.230 878.790

839.760 887.410 759.390

588.351 696.671 804.945

563.400 562.220 630.120

614.950 481.050 531.160

UCS

734.663

646.991

719.318

730.497

714.252

724.672

565.022

636.034

563.978

573.160

478.926

943.440

875.990

828.860

696.656

585.250

542.387

Average UCS (kPa)


APPENDIX J – Test Results

94

Density (kN/m3)

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

Test No.

9

10

11

12

13

14

15


16

20 1

20 - 2

20 - 3

21 - 1

21 - 2

21 - 3

22 - 1

22 - 2

22 - 3

48

48

48

48

48

48

48

48

48

48

48

48

48

48

48

48

48


0.5

0.5

0.5

0.25

0.25

0.25

0

0

0

0

0

0.5

0.5

0.25

0.25

0

0

Fibre (%)

0

0.1 0.3 0.5 1 1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

5

3

1

5

3

1

5

3

1

0

0.1 0.3 0.5 1 1.5

1.5

0

0

0

0

0

0

14

14

14

14

14

14

14

14

14

14

1

14

1

14

1

14

1


0

0

0

0

0

0

PVA (%)

3

3

3

3

3

3

3

3

3

1

1

3

3

3

3

3

3


To-do

9/05/2016

27/04/2016

27/04/2016

18/04/2016

29/03/2016

6/04/2016

6/04/2016

18/04/2016

6/04/2016

21/03/2016

6/04/2016

29/03/2016

22/03/2016

Mix date

Complete

10/05/2016

28/04/2016

28/04/2016

19/04/2016

30/03/2016

7/04/2016

7/04/2016

19/04/2016

7/04/2016

22/03/2016

7/04/2016

30/03/2016

23/03/2016

Sample prep date

Curing

25/05/2016

13/05/2016

13/05/2016

4/05/2016

14/04/2016

8/04/2016

22/04/2016

20/04/2016

22/04/2016

23/03/2016

22/04/2016

14/04/2016

24/03/2016

Test date

TABLE 31 – Low Density Tests & Results

103 103 103 104 104 104 104 103 104 104 104 102 103 103

102 101 101 101 102 101 101 102 101

103 103 103 102 103 102 101 101 101

103 103 103 104 104 103 102 103 103

102 101 101 101 102 101 101 102 100

103 103 103 102 103 102 101 101 101

104 100 103 103 103

104 103 102 103 104

103 100 102 103 104

104 104 103

104 105 105

104 105 105 104 104 103

100 101 103

102 102 102

102 102 102 103 102 103

104 103 107

101 101 101

101 101 101 104 102 109



49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

49.32

48.14 48.91 48.75 47.56 47.67 46.98 47.54 47.23 47.17

46.55 46.24 45.87 47.01 47.23 46.68 46.43 46.79 47.06

47.6 47.29 47.44 47.21 46.87 46.77 46.75 47.02 46.95

44.03 46.46 47.11 43.68 43.50

47.15 47.34 45.56 44.98 44.88

46.5 46.54 46.8

43.97 44.87 45.12

47.5 43.71 44.2

46.27 46.12

45.59 47.318

45.61 45.76 46.25


177.150 199.680 200.712 196.842 207.462 207.562 187.209 229.247 254.600

200.756 200.536 213.939 212.506 209.969 223.599 263.588 263.416 288.625

106.990 112.720 109.280 88.810 99.960 108.590 101.460 137.260 143.420

66.210 78.950 179.910 205.370 247.000

24.940 32.330 37.150 63.810 91.840

24.490 33.260 33.950

17.610 14.860 21.910

53.930 50.720 57.100

12.380 15.650

18.650 20.360

17.720 17.200 15.310

Load at Peak (N)

223.685

203.955

192.514

271.876

215.358

205.077

127.380

99.120

109.663

155.488

50.014

30.567

18.127

53.917

DATA CORRUPT

14.015

19.505

DATA CORRUPT

16.743


80.986 89.200 89.600 85.900 93.800 93.700 84.400 99.600 112.500

93.779 96.600 100.000 97.900 98.900 105.300 119.500 122.500 129.500

48.410 49.830 49.890 39.560 44.520 48.310 48.380 61.530 65.030

29.040 37.420 76.080 93.650 112.780

9.890 13.170 16.530 27.880 40.760

10.390 13.620 13.910

7.230 6.240 8.890

23.010 20.610 23.560

5.070 6.270

7.690 10.090

7.190 6.790 6.210

UCS

98.833

91.133

86.595

123.833

100.700

96.793

63.280

44.130

49.380

69.800

21.650

12.640

7.460

22.400

5.670

8.890

6.730

Average UCS (kPa)


95


APPENDIX K – Initial Soil Trials FIGURE 58 – 63 – Initial Soil Trials A


96

Final Year Project Report FIGURE 64 – 66 – Initial Soil Trials B


97


APPENDIX L – Risk Assessment – Testing TABLE 32 – Risk Assessment - Testing


98



99



100



101



102



103


APPENDIX M – Plant & Equipment Risk Assessment TABLE 33 – Plant & Equipment Risk Assessment


104



105



106



107



108



109



110



111



112


APPENDIX N – CQU Resources Agreement


113

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