development of a methodology for assessing the

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validation of new asphalt binder and mix properties under cold temperature in accordance ... equipment testing in the laboratory upgrading exercise. .... equipment that is of high importance for many experiments instead of having ... following section. .... 0.3333. 0.7851. 6.938. Pine AFGC 125X. 0.2632. 0.5. 0.2793. 0. 0.7048.
4e Conférence spécialisée en génie des transports de la Société canadienne de génie civil 4th Transportation Specialty Conference of the Canadian Society for Civil Engineering Montréal, Québec, Canada 5-8 juin 2002 / June 5-8, 2002

DEVELOPMENT OF A METHODOLOGY FOR ASSESSING THE TECHNICAL AND ECONOMIC BENEFITS OF ASPHALT PAVEMENT LABORATORY EQUIPMENT S. ChanA, S. L. TigheB A Department of Civil Engineering, University of Waterloo, Canada B Department of Civil Engineering, University of Waterloo, Canada ABSTRACT: Over the past decade, there have been tremendous advances made to both the field and laboratory testing procedures in pavement engineering. To enhance the University of Waterloo’s capabilities to carry out research and teaching in roads and pavement technology, it was critical to upgrade the existing laboratory facilities. This paper describes the development of a methodology, which can be used by contractors, consultants and private agencies to evaluate laboratory equipment in terms of various considerations and needs. A technical weighting methodology to assess the needs of the potential laboratory equipment based on quality control, quality assurance, research and/or teaching objectives was developed. The cost effectiveness analysis access the most suitable model of laboratory equipment from different manufacturers, based on various objectives or parameters against the cost of the equipment.

1.

INTRODUCTION

Pavement performance at extreme low temperatures can dramatically affect long-term performance. The research infrastructure proposed at the University of Waterloo will be used to focus on the evaluation and validation of new asphalt binder and mix properties under cold temperature in accordance with SHRP and Superpave. The introduction of new testing equipment can be very expensive. However, based on limited budgets and overall testing objectives, it can be difficult to decide on which equipment to purchase. Therefore, a methodology to select proper low temperature pavement testing equipment is essential. In this paper, potential asphalt pavement testing equipment is discussed. The case study focuses on asphalt paving equipment. However, it is intended to apply the methodology to concrete pavement equipment testing in the laboratory upgrading exercise. A technical and economic effectiveness analysis is used to select the best-suited equipment for the proposed low temperature pavement testing laboratory. 2.

POTENTIAL PAVEMENT EQUIPMENT

There are many different types of pavement testing equipment in the market. Most of the test equipment has a unique testing purpose. Thus, it is crucial to first identify the purpose of the pavement testing equipment. In various other considerations must also be identified. This case primary emphasis is given to low temperature pavement testing laboratory equipment.

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For example, to facilitate a complete pavement-testing laboratory, it is essential to introduce an asphalt concrete compactor for the purpose of asphalt mix testing. The new Superpave Gyratory Compactor (SGC) is an asphalt concrete specimen compactor which has been proposed by SHRP. The cost associated with preparing SGC specimen is relatively less expensive when compared to preparing the ordinary beam specimen. Also, it is more difficult to prepare a beam specimen compared to the SGC specimen. Therefore, cost and time considerations of sample preparation are important factors in acceptance. In this case the SGC specimen becomes more universal and widely used in the industry because of its time and cost efficiencies. Loaded Wheel Testers (LWTs) are accelerated laboratory wheel-tracking device to simulate field performance. The existing LWTs are mainly used as a rutting prediction test (Cooley et al. 1999). The testing temperatures range between 4 ° C to 100 ° C. The LWTs can simulate the cold temperature environment to predict pavement performance under low temperature. There are also various Superpave low temperature testing equipment, such as Bending Beam Rheometer, Direct Tension Test, Superpave Shear Testers, and Indirect Shear Testers. Also, there is a Thermal Stress Restrained Specimen Test (TSRST) adopted the use of an environmental chamber to cool the asphalt concrete specimen during the test. Table 1 below summarizes the potential pavement testing equipment for the purpose of the low temperature pavement laboratory. Table 1. Overview of Potential Asphalt Pavement Laboratory Equipment Test Equipment Purpose Superpave Gyratory Compactor (SGC) To compact asphalt concrete specimen for testing and Superpave mix design verification. Loaded Wheel Testers (LWTs) Evaluate rutting, fatigue, thermal cracking, and predict field performance of flexible pavement. Bending Beam Rheometer (BBR) Measure binder properties at low temperature and to measure load deformation. Direct Tension Test (DTT) Measure binder properties at low temperature regarding ductility and stiffness. Superpave Shear Tester (SST) Evaluate rutting and fatigue cracking susceptibility of asphalt mixture using ECS through 6 programmed tests. Indirect Tensile Tester (IDT) Evaluate thermal cracking susceptibility and the viscoelasticity of asphalt concrete. Thermal Stress Restrained Specimen Determine low temperature cracking resistance and to Test (TSRST) measure tensile stress of asphalt concrete. 3.

TECHNICAL BENEFIT ANALYSIS

The potential pavement testing equipment as discussed previously are relevant to the low temperature pavement testing. A technical weighting methodology is used to assess the needs of those laboratory equipment for the research and teaching purposes at the University of Waterloo. The technical benefit analysis developed measures the effectiveness of the equipment against the criteria for obtaining laboratory equipment for the lab. A list of technical weighting questions is generated to evaluate the needs for the particular piece of equipment to the University. A methodology for stakeholders including academic, consultant, contractor, and public agencies has been developed in this research. In addition, each piece of equipment has been evaluated using this methodology. The technical weighting template contains 15 questions to assess the importance of these factors against the industries needs. The ranking of each question for the technical assessment ranges between 0 and 5. The higher the number, indicates the higher the importance of this factor to the user. After each question is ranked, the total of all fifteen questions is calculated. This dictates whether the equipment is worthwhile to be purchased according to the individual industry needs. The need for purchasing the equipment, as indicated by the total score follows the scale in Table 2:

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Table 2. Technical Benefit Total Score Categorization TOTAL SCORE CATERGORY 0 – 25 Should not consider to purchase the equipment 26 – 50 Should consider purchasing the equipment 51 – 75 Should purchase the equipment The numerical measures are justified by dividing the total score into three categories. The higher the number indicates higher importance of the factors to the industry, it reflects the significance of the equipment. With rankings from 0 to 25 reveals the importance level is low, thus this equipment should not be considered. Whereas rankings from 26 to 50 result in an intermediate category and the equipment should be considered for the laboratory. Lastly, the highest-ranking category with rankings from 51 to 75 indicates that the equipment should be purchased. Table 3 shows the technical weighting questions template that can be used by different stakeholders. Note the first question focuses on Canada’s environment as this is the primary focus of the laboratory. If this were being used for another laboratory, then we might consider a different question. Table 3. Technical Weighting Questions Template TECHNICAL WEIGHTING QUESTIONS 1) Applicability to Canada’s environment with emphasis on cold conditions 2) Availability of resources 3) Availability of funding 4) Availability of laboratory space 5) Flexibility to test wide range of samples or specimens 6) Energy consumption is LOW for the equipment 7) Test time per sample or specimen 8) Accuracy of result from the equipment 9) Durability of equipment 10) Easy to operate with user manual 11) Usage frequency of the equipment to the laboratory 12) Equipment portable to the field 13) Applicability of equipment for research 14) Applicability of equipment for specification 15) Applicability of equipment for training

0

1

2

3

4

5

TOTAL: (Totalling the ranks) The following provides a detail explanation of the technical weighting questions as shown in Table 3. 1) Applicability to Canada’s environment with emphasis on cold conditions The purpose of the low temperature pavement testing laboratory is to obtain equipment that can simulate the cold temperature environment and perform experiments to examine the behaviour of the material under low temperature. 2) Availability of resources In order to obtain the necessary laboratory equipment, it is essential to arrange the resources. Such as sufficient staff and laboratory technicians available to run the equipment and enough electric supply for the equipment in the specified laboratory. 3) Availability of funding Funding is required to purchase necessary laboratory equipment. Therefore, it is important to consider the funding availability in the technical assessment.

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4) Availability of laboratory space Regardless of funding and resource availability, it is crucial to consider the availability of the laboratory space for the equipment. Some of the equipment are relatively large in size and space availability is critical. 5) Flexibility to test wide range of samples / specimens Some equipment is flexible to test many size and types of samples; whereas some other equipment can only perform a specific test with a definite size and type of specimen. Flexibility of the equipment reflects the usefulness of the machine in many other ways and provides the capability to perform a range of experiments with only one machine. 6) Energy consumption is low for the equipment It is also preferable to purchase equipment that is in an environmentally friendly in terms of energy consumption. Ideally, the equipment should require a low energy consumption. Therefore, this is also a critical factor for the technical assessment. 7) Test time per sample or specimen It is important to assess the test time per sample or specimen as it reflects the turn over time required for using the equipment. It is better to have a shorter test time per sample, therefore more specimens can be tested in a given period of time. 8) Accuracy of result from the equipment One of the critical factors in assessing the equipment is to examine the accuracy of the result provided by the equipment. 9) Durability of equipment The equipment being purchased should be durable so that less maintenance and repair is required in its service life. 10) Easy to operate with user manual It is beneficial to purchase equipment that is easy to operate. 11) Usage frequency of the equipment to the laboratory The usage frequency of the equipment indicates the importance of the equipment to the research. It is valuable to purchase equipment that is of high importance for many experiments instead of having equipment used rarely. 12) Equipment portable to the field Some equipment are useful to the fieldwork, hence it is essential to consider if the equipment is portable to the field. It also reflects the flexibility of the equipment if it is easy to carry around. 13) Applicability of equipment for research For the purpose of a research laboratory, it is necessary to assess the applicability of the equipment for research. It is also an indication if the equipment and the test performed are valuable to the research field. 14) Applicability of equipment for specification For the purpose of a research laboratory, it is crucial to verify the specification by performing relevant experiments. Therefore, it is important to assess the applicability of the equipment for specification. 15) Applicability of equipment for training Suitability for training and teaching will be an important future consideration in establishing test facility. Therefore, it is critical to assess the applicability of the equipment for training. It would be more valuable to obtain equipment that is applicable for training and teaching purpose. 3.1

Generic Technical Weightings For Stakeholders

A rational for the various stakeholders has been developed for the general technical weighting. The stakeholders in the pavement industry include academic, consultant, contractor and public agency. Each of these industries is not identical in terms of its significant factors. Therefore, it is necessary to develop a rational specific for the stakeholder to obtain the most appropriate ranking for the equipment. Academic is generally focused on the research and teaching. Consultants are concerned with testing to ensure the product meets the specification to verify the design for the public agency. Contractors are primarily interested in the test time per sample to provide a high turn over rate for quality control purpose. Public agencies focused on developing new specifications and verification of the test result. Table 4 shows the generic technical weightings for academic, consultant, contractor and public agency.

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Table 4. Generic Technical Weightings For The Industries TECHNICAL WEIGHTING QUESTIONS ACAD* CONS* CONT* 1) Applicability to Canada’s environment with emphasis on 5 1 1 cold conditions 2) Availability of resources 4 3 1 3) Availability of funding 4 5 2 4) Availability of laboratory space 4 4 2 5) Flexibility to test wide range of samples or specimens 4 4 3 6) Energy consumption is LOW for the equipment 2 1 1 7) Test time per sample or specimen 4 5 4 8) Accuracy of result from the equipment 5 5 4 9) Durability of equipment 5 2 4 10) Easy to operate with user manual 2 1 3 11) Usage frequency of the equipment to the laboratory 4 3 3 12) Equipment portable to the field 2 2 5 13) Applicability of equipment for research 5 1 1 14) Applicability of equipment for specification 4 4 5 15) Applicability of equipment for training 3 1 1 TOTAL: 57 42 40 * ACAD = Academic; CONS = Consultant; CONT = Contractor; PAGY = Public Agency

PAGY* 3 4 5 5 4 2 5 5 3 1 5 3 1 5 2 53

Table 4 provides a summary of the technical weighting for academic, consultant, contractor and public agencies that was developed by surveying stakeholders. According to this generic technical weighting, the industries have different critical factors in assessing the needs for the equipment. It reveals in this example that academic and public agencies should purchase the equipment; whereas the consultant and contractor should consider purchasing the equipment although it is not a necessity. For the purpose of this report, a detailed technical benefit analysis is provided for the academic industry in the following section. 3.2

Laboratory Equipment Technical Assessment for Academic

Technical weightings provide a methodology in assessing the needs of laboratory equipment for the purpose of research testing. Each of the potential laboratory equipment discussed previously is going to be assessed using this technical weighting method. According to Table 5 in the following page, the technical assessment weighting is 58, which indicates the importance of the equipment to the laboratory is high. Thus, a loaded wheel tester should be purchased for the proposed laboratory. The remaining potential laboratory equipment is to be assessed using the same technical weighting template (Table 3) in order to evaluate the needs for the equipment. To summarize the result from the technical weighting assessment for each of the potential laboratory equipment, refer to Table 6 in the following page. Table 6 indicates that all of the potential pavement equipment has very high technical weighting and they all fall under the highest weighting category between weightings of 51 to 75. According to this technical weighting assessment, all of these potential pavement equipment are valuable to the University and should be purchased for the proposed laboratory.

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Table 5. Technical Weighting Assessment for Loaded Wheel Tester TECHNICAL WEIGHTING QUESTIONS 1) Applicability to Canada’s environment with emphasis on cold conditions 2) Availability of resources 3) Availability of funding 4) Availability of laboratory space 5) Flexibility to test wide range of samples or specimens 6) Energy consumption is LOW for the equipment 7) Test time per sample or specimen 8) Accuracy of result from the equipment 9) Durability of equipment 10) Easy to operate with user manual 11) Usage frequency of the equipment to the laboratory 12) Equipment portable to the field 13) Applicability of equipment for research 14) Applicability of equipment for specification 15) Applicability of equipment for training

0

1

2

3

4 X

5 X X X

X X X X X X X X X X X TOTAL: 58

Table 6. Summary of Technical Weighting Assessment for Potential Equipment Potential Pavement Equipment Technical Weighting Total Superpave Gyratory Compactor (SGC) 61 Loaded Wheel Testers (LWTs) 58 Bending Beam Rheometer (BBR) 62 Direct Tension Test (DTT) 59 Superpave Shear Tester (SST) 60 Indirect Tensile Tester (IDT) 61 Thermal Stress Restrained Specimen Test (TSRST) 60 4.

COST EFFECTIVENESS ANALYSIS

The cost effectiveness analysis provides a methodology in assessing the most suitable model of laboratory equipment from different manufacturers. The most appropriate alternative is selected by preference on the importance of various objectives or parameters on the specific equipment. The cost-effectiveness analysis developed utilizes a composite index based on constituent costs and measures of effectiveness by which to rate each alternative. The following steps were used in establishing a composite index (Saccomanno 1999): a) Generate objectives or parameters and select appropriate measures (numerical quantification) b) Assign weights (W) to each objective based on importance. The weightings are justified according to the importance level of each objective. c) Standardize ratings to eliminate the effect of using different scales, while ensuring all ratings are same in direction (ie, higher rating is more favourable for all parameters). [1]

SRij = Rij / ΣRij

d) Estimate weighted Composite Index (CI) for all objectives or parameters [2]

CI = ΣWj SRij

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e) Plot a graphical representation of CI vs. Cost and examine the best alternative by selecting a relatively high CI (more effective) with minimal cost. The cost effectiveness analysis is a good screening tool and not biased by reliance of estimated cost alone and reflects preferences by selecting appropriate weighting for each objectives or parameters. 4.1

Sample Cost Effectiveness Analysis Using Superpave Gyratory Compactor

The potential pavement testing equipment discussed previously has more than one alternative. It is necessary to select the best-suited equipment for the purpose of each test. A sample cost effectiveness analysis using Superpave Gyratory Compactor (SGC) is provided in this section. The remaining laboratory equipment alternatives are to be assessed using the same methodology. There are five potential alternatives for SGC discussed in the previous section. Using the cost effectiveness analysis, the most appropriate alternative can be identified. First, is to generate objectives and assign weighting as shown in Table 7. Table 7. Generate Objectives and Assign Weighting for SGC OBJECTIVES WEIGHTING COMMENTS No. Gyration per test 10 Indicate consolidation of specimen. Angle of Gyration 7 Flexibility of angle adjustment. Consolidation Pressure 5 Reflect the time per test. Portable to Field 3 Applicability to use in field. Weight of equipment 3 Easy to handle. The objectives are generated according to the SGC specification in Table 7. These objectives are the significant factors to be considered to determine the practicability of the equipment. The importance levels are quantified using the assigned weighting in ascending order. The number of gyrations per test is more important as it indicates the consolidation of specimen; therefore having a highest rating of 10 assigned. The angle of gyration demonstrated the flexibility of the machine, which is also a very important factor, therefore a weighting of 7 is assigned. The remaining parameters are weighted accordingly depending on the relative importance level to the equipment. The second step is to quantify the alternatives by assigning a rating to the alternatives as shown in Table 8. Table 8. Quantify Alternatives into Numerical Values for SGC OBJECTIVES ALTERNATIVES RATING No. Gyration per test 999 999 280 280 300 300 Angle of Gyration Adjustable (0.5 to 2 degree) 5 Non-adjustable (2 degree) 0 Consolidation Pressure 1000 kPa 5 600 kPa 0 Portable to Field Portable 3 Not Portable 0 Weight of equipment 364 kg 364 500 kg 500 157 kg 157 265 kg 265 408 kg 408

COMMENTS Use same number of gyration per test as the rating. Preferred high gyration per test. Flexibility to have adjustment is preferred. Higher pressure reflect a shorter time for compaction (preferred). Preferred to have portable equipment. Use the weight as the rating. Preferred to have light weight for easy handle.

The alternatives are being transformed to numerical value for cost effectiveness measures. The objectives for the number of gyration per test and weight of equipment used the actual values for the

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ratings. The angle of gyration with rating of 0 represent the angle of gyration is 1.25° with no adjustment. A rating of 5 represent the angle of gyration is between 0.5° and 2.0° (adjustable). The adjustable angle of gyration is more favourable; thus, it has higher measures of 5. It is important to note that for most testing, the angle would be set at the specification and not adjusted. However, for research purposes one might want the flexibility to adjust the angle. Correspondingly, a higher consolidation pressure is preferred as it indicates a shorter compaction time required; a higher rating of 5 is assigned for 1000 kPa and a rating of 0 for 600 kPa. Similarly, if the machine is portable to the field, it is more favourable with higher measures of 3 instead of having 0 rating for equipment that is not portable. The following Table 9 summarizes the numerical quantification for each of the equipment alternatives. Table 9. Summary of SGC Equipment Numerical Rating Equipments Cost Consolidation Angle of ($CDN) Pressure (kPa) Gyration Pine AGF1A 40,024 600 0 Pine AFGC 125X 49,714 1000 5 Pine AFGB1A 42,300 600 0 Trolxer 4141 37,192 600 0 Troxler 4140B 43,392 1000 5

No. gyration per test 999 999 280 300 999

Portable 3 0 3 3 0

Weight (kg) 364 500 157 265 408

The next step is to standardize the rating (Eq.1) and calculate composite index (Eq.2) for each equipment as shown in Table 10. Table 10. Standardize Ratings and Composite Index for SGC Equipments Consolidation Angle of No. gyration Pressure (kPa) Gyration per test Pine AGF1A 0.1579 0 0.2793 Pine AFGC 125X 0.2632 0.5 0.2793 Pine AFGB1A 0.1579 0 0.0783 Trolxer 4141 0.1579 0 0.0839 Troxler 4140B 0.2632 0.5 0.2793

Portable 0.3333 0 0.3333 0.3333 0

Weight (kg) 0.7851 0.7048 0.9073 0.8436 0.7591

Total CI 6.938 9.723 5.294 5.159 9.886

The above Table 10 shows the standardized ratings and calculated composite index (CI) according to the equations discussed previously (Eq.1 and Eq.2). Ensure all the ratings are at the same direction, meaning that higher numerical ratings represent a more favourable situation for all objectives. In this case, everything is in the same direction of having higher rating the better except the rating for the weight of the equipment. The weight of the equipment is preferred to be lighter for the purpose of easier handling. Therefore, this should be considered when computing the standardization number. To encounter the difference in direction for the equipment weight, subtract the calculated standardization value by one to accommodate the difference. The composite index (CI) is calculated using the formula as discussed previously (Eq.2). A higher composite index (CI) represents a higher preference on that piece of equipment. It has been previously defined by incorporating the weighting (W) and rating (R) of each alternative. The CI value does not have a definite range of numbers, and it is evaluated on a relativity basis by comparing the set of CI for the specific case study. Therefore, to select the best-suited equipment is to examine the cost and CI relationship. The final step is to plot a graphical representation of composite index (CI) as a function of the cost of the equipment. According to Figure 1 below, it indicates that the best machine having the highest composite index of 9.886 (CI) belongs to Troxler 4140B. Therefore, this would be the best alternative as it has the highest CI value and yet a reasonable price. Table 11 below shows the overall ranking for the Superpave Gyratory Compactor (SGC).

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Composite Index (CI)

12.000 10.000

9.886

9.723

8.000 6.938 6.000

5.294

5.159 4.000 2.000 0.000 30,000

35,000

40,000

45,000

50,000

55,000

Cost ($)

Figure 1. SGC Composite Index verse Cost Selection Table 11. Overall Cost Effectiveness Ranking for SGC Ranking SGC Model Composite Index 1 Troxler 4140B 9.886 2 Pine AFGC 125X 9.723 3 Pine AFGC 1A 6.938 4 Troxler 4141 5.159 5 Pine AFGB 1A (Brovold) 5.294

Cost ($CDN) $43,392 $49,714 $40,024 $37,192 $42,300

Overall, the best suitable equipment is selected based on high composite index and low equipment cost. Engineering judgement applies to interpret the CI and equipment cost relationship to achieve the maximum efficiency. 5.

CONCLUSION

This paper discusses a methodology to assist with the redesign and modernization of the existing research infrastructure, particularly in the low temperature pavement research area for University of Waterloo. The case study focuses on asphalt pavement equipment. An unique analysis method has been designed to determine the technical and economic costs and benefits. The technical assessment is to evaluate the needs of purchasing the equipment to the proposed laboratory; the cost effective analysis is to select the best alternatives from different manufacturers’ equipment. Overall, different stakeholders can use the technical and economic methodology described in this paper to evaluate laboratory equipment in terms of various considerations and needs. 6.

ACKNOWLEDGEMENT

The authors gratefully acknowledge funding support provided by the National Science and Engineering Research Council and Professor Ralph Haas at the University of Waterloo. I would also like to thank Mr. Ken Bowman from the University of Waterloo for his extensive advice and knowledge on this research topic.

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REFERENCES

Cooley, L., Kandhal, P., Buchanan, S., Fee, F., and Epps, A. (2000) Loaded Wheel Testers in the United States: State of the Practice, TRB E-Circular E-C016, National Academy Press, Washington, D.C. Saccomanno, F. (1999) Supplementary Course Notes of Civ. 392 Engineering Economics, University of Waterloo, Department of Civil Engineering, Waterloo, Ontario.

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