studies on effect of zycotherm additive on strength

STUDIES ON EFFECT OF ZYCOTHERM ADDITIVE ON STRENGTH CHARACTERISTICS OF POLYMER MODIFIED BITUMEN CONCRETE BY 1. NINGAPPA.B.A1 2. AMARNATH.M.S2

1. Student, M.E (Highway Engineering), UVCE, Bangalore University, Bangalore. E-mail: [email protected] 2. Professor, Dept. of Civil Engineering, UVCE, Bangalore University, Bangalore. E-mail: [email protected] ABSTRACT Over the past few decades the road traffic has grown significantly. So, The good design of Polymer Modified Bituminous Concrete mix (PMBC) is expected to result in a mix which is adequately strong, durable and resistive to fatigue and at the same time environment friendly and economical. A mix designer tries to achieve these requirements through a number of tests on the mix with varied proportions of material combinations and finalizes the best one. The Modification of bitumen is one of the alternate solutions to improve the deficiencies of conventional bitumen. Cracking, rutting etc, are few failures in pavement, which is due to high intensity of traffic, over loading of vehicles and significant variations in daily and seasonal temperature of the pavement. Further, The filler used in bituminous mix plays a main role in the performance of bituminous pavements. In the present study an attempt is made to assess the influence of zycotherm a Nanotech additive with Polymer Modified Bitumen (PMB40) fulfills many requirements and purposes and lime as a filler in PMBC mix. The mix design is carried out, so as to achieve a mix having sufficient bitumen to ensure a durable pavement with sufficient stability to satisfy the demands of traffic without distortion. The test results are obtained in the present study, it is observed that with hydrated lime 2% as filler material and zycotherm 0.125% as additive results in satisfactory Marshall Properties as per MoRTH V revision. The PMBC mix with zycotherm as additive has exhibited the highest Marshall Stiffness, Indirect Tensile Strength (ITS) and Tensile Strength Ratio (TSR) as compared with that of PMBC mix without zycotherm additive. INTRODUCTION The rapid growth of cities in recent years resulted in a lot of transportation. Road surface have experienced a significant increase in traffic volume and higher magnitudes of load. In tropical countries, the normal temperature in summer time will make the bitumen material become softer. This will also reduce the service life of the road. The two main damages in flexible pavements are permanent deformation and fatigue cracking. Therefore, the issue of improving qualities and properties of bituminous material is made by using Nanotechnology additive and Polymer Modified Bitumen (PMB40). The bituminous mix design aims to determine the proportion of coarse aggregates, fine aggregates, filler, additive and bitumen to produce a mix which is workable, strong, durable and economical. The materials like Polymer Modified Bitumen (PMB40), hydrated lime as filler may improve the properties of mix. By using additives in mix can reduce the Optimum Bitumen Content (OBC) and increses in the strength properties like ITS and TSR of the Polymer Modified Bituminous Concrete (PMBC) mix compared to conventional BC mix, because of their excellent binding characteristics and water proofing properties at low cost. Now a days due to drastic increase in traffic, Use of modified bitumen and Nanotech additives are dominating and taking main role in the improvement of Marshall and strength properties of PMBC mix. Also which may reduces the OBC compared to with that of PMBC mix without zycotherm additive. OBJECTIVES OF THE PRESENT STUDY  To determine the Marshall properties of bituminous concrete (Grade II) mix using Polymer Modified Bitumen (PMB40) as a binder.  To Study the effect of 2% lime as filler and a Nanotech zycotherm as additive on Marshall properties.  To determine the optimum bitumen content of PMBC Mix prepared using the different percentages of zycotherm a Nanotech additive (0%,0.1%,0.125%,0.15%,0.175%) by Marshall Method.  To determine the Indirect Tensile Strength (ITS) and Tensile Strength Ratio (TSR) of PMBC Mix prepared using the different percentages of zycotherm a Nanotech additive (0%,0.1%,0.125%,0.15%,0.175%) at optimum bitumen content. LITERATURE REVIEW Poornaprajna S and Anjum, (2014) Conducted Marshall stability test on bituminous concrete mix with polyphosphoric acid as additive. The test results revealed that the Bulk density, Marshall stability increases at 5% bitumen content and 3% polyphopshoric acid additive. Ziari Hassan et al, (2012) studied on influence of Bentonite as additive in bituminous mix and they found that the addition of additive, Marshall stability and flow improved in bentonite modified mixtures in compare with unmodified mixtures. While using 20%

bentonite (weight percent of bitumen) improves the properties of asphalt mixture more in comparison with the other contents and this content is introduced as optimum bentonite content in their research. Dallas N. Little et al (2001) Carried out investigation on the effect of hydrated lime as filler on Marshall properties of BC mix and they described that, It improves moisture susceptibility and durability. Thus, hydrated lime is an additive that increases pavement life and performance. Devendra K et al (2014) investigated the effects of modified binder on marshall properties and the results revealed that the PMB40 is the Adhesion Promoter in BC mix and it improves the Marshall Properties. The Nanotechnology using zycotherm additive in Bituminous Concrete Mix results adequately strong and durable pavement with high fatigue life . this additive is found to be environment friendly and economical. The technology providers of Nanotech additive called zycotherm claim that the zycotherm is chemically reactive anti-stripping nanotechnology agent for making roads durable. Upon mixing with hot mix binder, Zycotherm reacts with the gravel and improves the wetting and spreading power of chemically modified binder on inorganic surfaced of gravels, sand and soil. It also improves binder-to-gravel adhesion and it can reduce the OBC in bituminous concrete mix. Zycotherm may eliminates bituminous mix de-bonding due to inadequate and incomplete coating coupled with moisture ingress, thereby increasing the durability of flexible pavements. The laboratory investigations are carried out to study the effect of zycotherm additive on properties of Polymer Modified Bituminous Concrete (PMBC) mix. EXPERIMENTAL INVESTIGATION MATERIALS USED IN THE PRESENT STUDY

AGGREGATES Aggregate mainly consisting of both coarse and fine aggregates. The coarse aggregate is the fraction of the aggregate components retained on a 2.36mm test sieve. Fine aggregate is the fraction of the aggregate components passing the 2.36mm test sieve and retained on 0.075mm test sieve. Basic engineering tests are conducted on aggregates used in this study and the properties of aggregates are given in Table1 Table 1 Test results of aggregates Particulars of Tests

Test results

Requirements as per IS 383:1970 Specifications

Aggregate impact value (%)

21.2

Max 24%

Los Angeles abrasion value (%)

23.6

Max 30%

27.58

Max 30%

0.15

Max 2%

Coarse aggregate

2.66

Min 2.5

Fine aggregates

2.63

Min 2.5

Flakiness and (Combined) (%)

Elongation

Index

Water absorption (%) Aggregate specific Gravity

BINDER Polymer Modified Bitumen (PMB40) acts as a binding agent to the aggregates, fines and stabilizers in bituminous mixtures. Binder provides durability to the mix. The characteristics of binder which affects the bituminous mixture behaviour are temperature susceptibility, visco-elasticity and aging. In this study PMB40 is used as binder. The test results are presented in Table 2 and The test results are satisfy the requirements as per IRC SP: 53-2010. Table 2 Test Results of Binder Test Results Particulars of tests

Requirements as per IRC SP-53-2010

37

PMB40+ Zycotherm 39

Softening point (Ring & Ball), °C

67.5

63.2

Min 60

Flash point, °C

279

276

Min 220

Ductility @27 °C ,cm

89.3

92.4

Min 50

Specific gravity

Penetration at 25°C, 100gm, 5 Seconds, 0.1mm

PMB40

30-50

1.03

1.03

Min 0.99

Elastic recovery @150C, %

81

82

Min 75

Separation (Difference in softening point ring ball)

1.7

1.5

Max 3oC

Thin Film Oven Test 0.9 0.4 Max 1.0  Loss in mass,%  Reduction in penetration of residue at 25oC,% 30 23.07 Max 35 FILLER Mineral filler consists of very fine, inert mineral matter that is added to the bituminous mix, to increase the density and enhance strength of the mixture. These fillers should pass through 75 micron IS Sieve. The fillers may be cement, stone dust, fly ash or hydrated lime. The filler material used in the study is hydrated lime. It is taken as 2% by weight of aggregate. The specific gravity obtained is 2.32. ADDITIVE Zycotherm is an advance generation Silane additive with multiple benefits. Zycotherm gives chemical bonding for extended moisture resistance, enables 100% Coating of Bitumen on aggregates and allows wider temperature zone for compaction, resulting in a pavement with extended life cycle. Zycotherm chemically modifies the aggregate surface from water loving to bitumen loving, gives strong permanent bonding of bitumen on the aggregates. In order to study the effect of zycotherm additive on Marshall properties of bituminous mix, The percentage of zycotherm additive was varied from 0.1% to 0.175%. Properties of zycotherm additive (As provided by the supplier) are shown in Table 3. Table 3 Specific Gravity of Zycotherm Additive

Specific gravity

Zycotherm

1.0

DESIGN OF BC MIX BY MARSHALL METHOD Marshall Stability test of a mix is defined as maximum load carried by a compacted specimen at a standard test temperature at 60 degree Celsius. The flow value is the deformation the Marshall Test specimen under goes during the loading up to the maximum load in 0.01mm units. The Marshall Stability test is applicable for hot mix design using bitumen and aggregates with maximum size of 25mm. In this method, the resistance to plastic deformation of cylindrical specimen of bituminous mixture is measured under load. There are two major features of Marshall Stability method of designing mixes are:  density voids analysis  Stability flow test. GRADATION OF AGGREGATES The aggregate gradation (Grading-2) was adopted for bituminous concrete mixes as per MORT&H (V Revision) specifications. PREPARATION OF SPECIMEN Total 70 numbers of bituminous concrete mix specimens were prepared by using Polymer Modified Bitumen (PMB40) with 4.75%,5.25%,5.75%,6.25% by weight of aggregate, hydrated lime 2% as a mineral filler. The zycotherm additive was varied from 0 to 0.175% by weight of binder. MARSHALL STABILITY TEST Marshall Test properties of Bituminous Concrete (BC) Grade II mixes confirming to (MoRTH-2013). The conventional Marshall Stability test was conducted on the specimens as per ASTM D 1559. The parameters such as Bulk density (Gb), Volume of Air Voids (Vv), Voids in Mineral Aggregates (VMA), Voids Filled with Bitumen (VFB), Stability (S) and Flow (F) were determined. Table 4 and 5 shows the results of marshall stability test without zycotherm additive. Table 4 Marshall Properties of PMBC mix without Zycotherm as additive Bitumen content, %

Marshall stability, kg

Flow, mm

Marshall Quotient, kg/mm

Bulk density, g/cc

Total air voids, %

Voids in Mineral Aggregates, %

Voids filled with bitumen, %

4.75

1545.1

3.9

396.179

2.327

5.576

16.308

65.907

5.25

1600.2

4.75

336.84

2.335

4.601

16.507

72.129

5.75

1808.1

4.8

376.687

2.354

3.208

16.353

80.379

6.25

1502.55

4.85

309.800

2.345

2.948

17.183

83.028

Table 5 Marshall Properties of PMBC mix without zycotherm as additive at optimum bitumen content Sl No

Marshall properties

Test result

Requirements as per Table 500-10 of MORT&H (V revision) Specifications

1

Optimum Bitumen Content, (%)

5.65

Min 5.4

2 3 4 5 6 7

Marshall Stability, kg Flow, mm Marshall Quotient, kg/mm Air voids,(Vv) % VMA, % VFB, %

1838.02 3.85 644.919 4.381 17.157 74.471

Min 1200 2.5 - 4.0 250-500 3.0 - 5.0 Min 14 65-75

The percentages of zycotherm additive was varied from 0.1 to 0.175% and the Marshall stability test were carried out at each zycotherm additive and OBC’s were determined. The Marshall properties at OBC with varying percentages of zycotherm additive are shown in Table 6 to 9. Table 6 Marshall Properties of PMBC mix using 0.1% zycotherm as additive at optimum bitumen content Sl No

Marshall properties

Test result

Requirements as per Table 500-10 of MORT&H (V revision) Specifications

1

Optimum Bitumen Content, (%)

5.72

Min 5.4

2

Marshall Stability, kg

1623.82

Min 1200

3

Flow, mm

4

2.5 - 4.0

4

Marshall Quotient, kg/mm

405.955

250-500

5

Air voids,(Vv) %

4.319

3.0 - 5.0

6

VMA, %

17.250

Min 14

7 VFB, % 74.964 65-75 Table 7 Marshall Properties of Bituminous Concrete mix using 0.125% zycotherm as additive at optimum bitumen content Sl No

Marshall properties

Test result

Requirements as per Table 500-10 of MORT&H (V revision) Specifications

1

Optimum Bitumen Content, (%)

5.48

Min 5.4

2

Marshall Stability, kg

2057.47

Min 1200

3

Flow, mm

3.2

2.5 - 4.0

4

Marshall Quotient, kg/mm

642.959

250-500

5

Air voids,(Vv) %

4.654

3.0 - 5.0

6

VMA, %

17.037

Min 14

7 VFB, % 72.695 65-75 Table 8 Marshall Properties of PMBC mix using 0.15% zycotherm as additive at optimum bitumen content Sl No

Marshall properties

Test result

Requirements as per Table 500-10 of MORT&H (V revision) Specifications

1

Optimum Bitumen Content, (%)

5.58

Min 5.4

2

Marshall Stability, kg

1888.42

Min 1200

3

Flow, mm

3.25

2.5 - 4.0

4

Marshall Quotient, kg/mm

581.052

250-500

5

Air voids,(Vv) %

4.217

3.0 - 5.0

6

VMA, %

16.868

Min 14

7

VFB, %

75

65-75

Table 9 Marshall Properties of PMBC mix using 0.175% zycotherm as additive at optimum bitumen content Sl No

Marshall properties

Test result

Requirements as per Table 500-10 of MORT&H (V revision) Specifications

1

Optimum Bitumen Content, (%)

5.78

Min 5.4

2

Marshall Stability, kg

1814.40

Min 1200

3

Flow, mm

3.0

2.5 - 4.0

4

Marshall Quotient, kg/mm

604.8

250-500

5

Air voids,(Vv) %

4.444

3.0 - 5.0

6

VMA, %

17.483

Min 14

7

VFB, %

74.579

65-75

Fig 1shows the Marshall properties of Polymer Modified Bituminous Concrete (PMBC) mixes with varying percentages of zycotherm additive.

Bulk density, g/cc

2.35 2.34 2.33 2.32 2.31 4.5

5

5.5

6

6.5

zycotherm 0.1% zycotherm 0.125% zycotherm 0.15% zycotherm 0.175% zycotherm

3 4.5

5

5.5

6

6

6.5

Bitumen content v/s total air voids without zycotherm 6 0.1% zycotherm 4 0.125% 2 zycotherm 0.15% 0 4.5 5 5.5 6 6.5 zycotherm 0.175% Bitumen content, % zycotherm 100

without zycotherm 0.1% zycotherm 0.125% zycotherm 0.15% zycotherm

80 VFB, %

VMA, %

Bitumen content, %

6.5

5.5

Bitumen content,%

Bitumen content v/s VFB

Bitumen content v/s VMA

4.5

5

0.125% zycotherm 0.15% zycotherm 0.175% zycotherm

8

Bitumen content, %

18 17.5 17 16.5 16 15.5

5 4

Bitumen content v/s Bulk densitywithout

2.36

Bitumen content v/s Flow without zycotherm 0.1% zycotherm

6 Flow, mm

Bitumen content v/s Marshall stability without zycotherm 0.1% zycotherm 0.125% zycotherm 0.15% zycotherm 4.5 5 5.5 6 6.5 0.175% Bitumen content,% zycotherm

Total air voids, %

Marshall stability, kg

2000 1800 1600 1400 1200 1000 800 600

60 40 20 0 4.5

5

5.5

6

Bitumen content, %

6.5

without zycotherm 0.1% zycotherm 0.125% zycotherm 0.15% zycotherm 0.175% zycotherm

Fig 1 Marshall Properties of PMBC mix using different dosages of zycotherm as additive Effect of zycotherm content on properties of Polymer Modified Bituminous Concrete mix. Table 10 shows a comparison of Marshall properties with different percentages of zycotherm additive at OBC.

Table 10 Comparison between PMBC mix prepared using zycotherm content from 0.1 to 0.175% and without zycotherm additive at OBC Sl No

Marshall properties

Lime, 2%

1

OBC (%)

Without Zycotherm 5.65

2

Marshall Stability, kg

1838.02

Zycotherm, 0.1% 5.72

Zycotherm, 0.125% 5.48

Zycotherm, 0.15% 5.58

Zycotherm, 0.175% 5.78

1623.82

2057.47

1888.42

1814.4

3

Flow, mm

3.85

4

3.2

3.25

3

4

Air voids,(Vv) %

4.381

4.319

4.654

4.217

4.444

5

VMA, %

17.157

17.250

17.037

16.868

17.483

6

VFB, %

74.471

74.964

72.695

75

74.579

STRENGTH CHARACTERISTICS OF BC MIX USING ZYCOTHERM ADDITIVE INDIRECT TENSILE STRENGTH TEST The indirect tensile strength test is carried out as per ASTM:D-4123-1995 to study the behaviour of bituminous mix. The split tensile strength of bituminous mixes is determined by applying a single compressive load to Marshall specimens which acts parallel to and along the vertical diametrical plane, through two curved steel strips 1.5mm wide with the same inside curvature as that of marshall specimens. A nearly uniform tensile stress is developed normal to the direction of the applied load and along same vertical plane causing specimen to fail by splitting along the vertical diameter. The results of Indirect Tensile Strength are shown in Table 11. Table 11 Indirect tensile strength of PMBC mix prepared using with different percentages of zycotherm additive Zycotherm content, % 0

Optimum bitumen cotent, % 5.65

ITS, kg/cm2 12.85

0.1

5.72

11.92

0.125

5.48

14.32

0.15

5.58

12.21

0.175

5.78

11.72

Fig 2 shows the variation of ITS with zicotherm content. Zycotherm content v/s ITS

ITS, kg/cm2

20 10

ITS Values 0 0

0.05

0.1

0.15

Zycotherm content, %

0.2

Fig 2 Zycotherm Content v/s Indirect tensile strength TENSILE STRENGTH RATIO (TSR) Moisture Susceptibility of PMBC mix can be determined by conducted TSR test as per specification. TSR is expressed as the percentage of average indirect tensile strength of the conditioned specimens to the average indirect tensile strength of the unconditioned specimens. The results are presented in Table 12. Table 12 Results of Tensile Strength Ratio (TSR) Indirect tensile Strength, Kg/cm2

Zycotherm Content, %

Optimum Bitumen Content

Unconditioned

Conditioned at 60° C

0

5.65

12.85

11.61

90.35

0.1 0.125

5.72

11.92

10.50

88.08

5.48

14.32

13.16

91.90

0.15

5.58

12.21

10.96

89.76

0.175

5.78

11.72

10.01

85.40

TSR %

DISCUSSIONS&CONCLUSIONS 1. The optimum bitumen content for PMBC mix prepared using 0%,0.1%,0.125%,0.15% and 0.175% of zycotherm as additive are found to be 5.65%,5.72%,5.48%,5.58% and 5.78% respectively. 2. Optimum dosage of zycotherm additive is found to be 0.125% by weight of binder. 3. The Marshall stability for PMBC mix prepared using 0%,0.1%,0.125%,0.15% and 0.175% of zycotherm as additive are found to be 1838.02, 1623.82, 2057.47, 1888.42 and 1814.4kg respectively. 4. Increase in dosage up to optimum point Marshall stability is increasing and further increase in the dosage beyond optimum point, results decrease in Marshall stability. 5. The Flow for PMBC mix prepared using 0%,0.1%,0.125%,0.15% and 0.175% of zycotherm as additive are found to be 2.85, 4, 3.2, 3.25 and 3mm respectively. 6. Increase in the Bitumen content results in increase in the Flow value for all PMBC mixes prepared with or without zycotherm as additive. 7. Total percentage air voids is found to be decrease as the bitumen content inreases for all PMBC mix prepared with or without zycotherm. 8. For optimum dosage of additive zycotherm Marshall properties satisfies the requirements as per the MoRTH (V revision) specification. 9. Indirect tensile strength and TSR are maximum at optimum zycotherm content. REFERENCES 1. Srikant , Keerthikumar , Pradeep B H and Varuna M, (2014),“Comparative evaluation of warm mix Asphalt containing reclaimed asphalt pavement for DBM II mix”, Journal of Civil Engineering Technology and ResearchVolume 2, pp.561-567. 2. Rohith N, and RanjithaJ, (2013), “A Study On Marshall Stability Properties Of Warm Mix Asphalt Using Zycotherm A Chemical Additive”,International Journal of Engineering Research & Technology (IJERT) Vol. 2 Issue 7. 3. PoornaPrajna S and Mohamed IlyasAnjum, (2014), “Effect of Poly Phosphoric Acid on Marshall Test Properties of Bituminous Concrete Mixes”,International Journal of Emerging Technology and Advanced Engineering, Volume 4, Issue 7, pp369. 4. Ziari Hassan, Divandari Hassan, BabagoliRezvan, Akbari Ali, (2012), “Influence of Bentonite Additive on Bitumen and Asphalt Mixture Properties”, World Academy of Science, Engineering and Technology Vol:6. 5. Khalid M. andEweed, (2011), “Polymeric Additives Effect on Mechanical Properties for Bitumen Based Composites” Eng. & Tech. Journal, Vol. 29, No.12. 6. Johnny Tran and Hugo Van Loon,“Indirect tensile strength of asphalt mixes in south Australia”. 7. Katman H.Y, Ibrahim M.R, Matori M.Y, S. Norhisham, Ismail N, Che Omar R, (2012), “Tensile Strength of Reclaimed Asphalt Pavement”, International Journal of Civil & Environmental Engineering ,Vol: 12 No: 03 14. 8. Devendra K, Patel A, Mishra B and Amin B, (2014),“Experimental Investigation of Warm Mix Using Rediset as additive with PMB 40 in Mix Design”, International Journal of Current Engineering and Technology, E-ISSN 2277 – 4106, P-ISSN 2347 – 5161. 9. Dallas N. Little and Jon A., (2001), “The Benefits Of Hydrated Lime In Hot Mix Asphalt”. 10. Rahman M. N. and Sobhan M. A, (2013), “Use of Non-Conventional Fillers on Asphalt-Concrete Mixture”, International Journal of Innovation and Applied Studies ISSN 2028-9324 Vol. 3 No. 4, pp. 1101-1109. 11. DebashishKar, Mahabir Panda and JyotiPrakashGiri, (2014), “Influence Of Fly-Ash As A Filler In Bituminous Mixes”,ARPN Journal of Engineering and Applied Sciences VOL. 9, NO. 6. 12. SatyakumarM, SatheeshChandranR. and MaheshM.S, (2013),“Influence Of Mineral Fillers On The Properties Of Hot Mix Asphalt”, International Journal of Civil Engineering and Technology (IJCIET), Volume 4, Issue 5. 13. Hassan H. Jony , Mays F. Al-RubaieandIsraa Y. Jahad, (2011),“The Effect of Using Glass Powder Filler on Hot Asphalt Concrete Mixtures Properties”, Building and Construction Engineering Department, University of Technology/ Baghdad. 14. IRC SP 53-2010 specification for Modified bitumen. 15. MoRT&H “Specifications for Roads and Bridge Works”- 2013, Fifth revision, Indian Roads Congress, New Delhi. 16. Khanna S.K. and Justo C.E.G, Highway Material testing (Laboratory Manual), Nemchand and Bros, Roorkee 1997. 17. Asphalt Technology And Construction Practices Instructor’s Guide, Educational Series No.1, Second Edition, Asphalt Institute, Lexington, Kentucky.