Validation of Performance-Based Specifications for Surface Asphalt Mixtures in Virginia

2021 ◽  
pp. 036119812110566
Author(s):  
Jhony Habbouche ◽  
Ilker Boz ◽  
Stacey D. Diefenderfer
Keyword(s):  
Field Performance ◽  
Performance Criteria ◽  
Mix Design ◽  
Asphalt Mixes ◽  
Performance Predictions ◽  
Asphalt Mix ◽  
Current Threshold ◽  
Test Threshold ◽  
Virginia Department ◽  
Threshold Criteria

The Virginia Department of Transportation (VDOT), like many owner agencies, is interested in ways to facilitate the increased durability of asphalt mixes in an effort to make its roadway network more sustainable, longer lasting, and more economical. The balanced mix design (BMD) method proposes to address this through the incorporation of performance criteria into mix design and acceptance. VDOT has committed to the implementation of the BMD method in an effort to improve asphalt mix performance. The purpose of this study was to continue advancing efforts toward implementation of BMD through the evaluation of 13 asphalt mixes using performance-indicating laboratory tests, validation of the initial performance tests selected for BMD use, and validation of the initial test threshold criteria. Based on the results, the asphalt pavement analyzer (APA) rut test, indirect tensile cracking test (IDT-CT), and Cantabro test were found suitable for continued use in BMD. The current threshold criteria for all three tests were found reasonable based on additional mix testing. The study recommends that APA rut test and IDT-CT results should be compared and correlated to fundamental rutting and cracking tests, respectively, as well as to performance predictions obtained from mechanistic-empirical pavement design simulations, and to field performance for full assurance that test threshold values are appropriate. It was further recommended to evaluate the Cantabro, IDT-CT, and APA rut tests to determine acceptable variability and establish precision statements.

Initial Approach to Performance (Balanced) Mix Design: The Virginia Experience

2019 ◽  
Vol 2673 (2) ◽  
pp. 335-345 ◽  
Author(s):  
Stacey D. Diefenderfer ◽  
Benjamin F. Bowers
Keyword(s):  
Performance Testing ◽  
Performance Criteria ◽  
Mix Design ◽  
Department Of Transportation ◽  
Innovative Methods ◽  
Asphalt Mix ◽  
Performance Additives ◽  
Virginia Department ◽  
Selection Of

Performance mix design (PMD) of asphalt mixtures, often referred to as balanced mix design, is a design methodology that incorporates performance testing into the mix design process. The Virginia Department of Transportation (DOT), like many owner agencies, is interested in ways to specify asphalt mix designs better in an effort to make its roadway network more sustainable, longer lasting, and more economical. By adding performance criteria through a PMD framework, that goal can be achieved. Further, a PMD framework should allow for the development of new, innovative methods to increase pavement recyclability, new performance additives, and other means to enhance pavement performance. This paper provides details and documentation of the approach being taken by the Virginia DOT in their efforts to develop a PMD specification. Aspects of development presented include PMD method options, selection of performance tests, and determination of acceptance criteria. A discussion about validating specifications with in-service performance data and addressing quality control and quality assurance is also provided. Although additional work is needed for full development and implementation, the methodology being applied has been found to provide useful outcomes for the Virginia DOT even in the initial stages of development.

scholarly journals A Method to Quantify Reclaimed Asphalt Pavement Binder Availability (Effective RAP Binder) in Recycled Asphalt Mixes

2019 ◽  
Vol 2673 (1) ◽  
pp. 205-216 ◽  
Author(s):  
Fawaz Kaseer ◽  
Edith Arámbula-Mercado ◽  
Amy Epps Martin
Keyword(s):  
Asphalt Pavement ◽  
Economic Benefits ◽  
Binder Content ◽  
Mix Design ◽  
Void Content ◽  
Reclaimed Asphalt Pavement ◽  
Asphalt Mixes ◽  
Reclaimed Asphalt ◽  
State Highway ◽  
Asphalt Mix

State highway agencies recognize the environmental and economic benefits of utilizing reclaimed asphalt pavement (RAP) in asphalt mixes. Currently, most agencies assume all of the RAP binder content is available for mix design purposes. However, the percentage of available or effective RAP binder in the asphalt mix is usually less than 100% and not quantified, which could yield dry asphalt mix with a high air void content, potentially leading to premature distress. The term available or effective RAP binder refers to the binder that is released from the RAP, becomes fluid, and blends with virgin binder under typical mixing temperatures. This study proposes a method to estimate the RAP binder availability factor (BAF) which can be used to adjust the virgin binder content in RAP mixes to ensure that the mix design optimum binder content is achieved. In this method, asphalt mixes were prepared so that, after mixing and conditioning, the RAP material can be separated from the virgin aggregate, which allows for a thorough evaluation of the extent of RAP binder availability in the asphalt mix. This method was verified in a preliminary experiment and then used to estimate the BAF of RAP from different sources, and a correlation between RAP BAF and the high temperature performance grade (PG) of each RAP source was established. Finally, factors affecting the RAP BAF were also evaluated such as mixing temperature, conditioning period, the use of recycling agents (or rejuvenators), and the method of adding the recycling agent to the mix.

New and Simpler Cracking Test Method for Asphalt Mix Designs

2017 ◽  
Vol 2631 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Soohyok Im ◽  
Fujie Zhou
Keyword(s):  
Field Performance ◽  
Cost Effective ◽  
Test Methods ◽  
Environmental Conservation ◽  
Test Method ◽  
Asphalt Pavements ◽  
Cracking Resistance ◽  
Cracking Behavior ◽  
Asphalt Mixes ◽  
Asphalt Mix

Because of environmental conservation and sustainability concerns, reclaimed asphalt pavements and recycled asphalt shingles are increasingly used in the asphalt paving industry to replace virgin asphalt and aggregate materials. However, these recycled materials are often highly aged and can cause cracking issues for asphalt pavements. Additionally, other factors such as binder additives, modifiers, and multiple warm-mix asphalt technologies can alter the performance of the mixtures both positively and negatively. The volumetric mix design alone is not sufficient for evaluating the potential cracking behavior of asphalt mixes. Although many cracking test methods are available, there is no widely accepted performance-related cracking test method that is practical enough for routine use in asphalt mix designs. This paper presents a newly developed, simple, and practical cracking test method for asphalt mix designs. The new cracking test method is repeatable, time- and cost-effective, easily implemented, sensitive to mix compositions, and well correlated to field performance. The new cracking test is performed at an intermediate temperature of 25°C and a loading rate of 50 mm/min. Furthermore, a unitless index is proposed as the cracking resistance indicator for evaluation of the cracking resistance of asphalt mixes. Additionally, the effectiveness of the new cracking test was validated with the test results from FHWA’s accelerated loading facility.

Critical Review of Voids in Mineral Aggregate Requirements in Superpave

1998 ◽  
Vol 1609 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Prithvi S. Kandhal ◽  
Kee Y. Foo ◽  
Rajib B. Mallick
Keyword(s):  
Film Thickness ◽  
Mix Design ◽  
Rational Approach ◽  
Asphalt Mixes ◽  
Mineral Aggregate ◽  
Superpave Gyratory Compactor ◽  
Asphalt Mix ◽  
Compactive Effort ◽  
Asphalt Content ◽  
Asphalt Film

Reports of increased difficulties in meeting the minimum voids in mineral aggregate (VMA) requirements have surfaced with the recent use of Superpave volumetric mix design. The low VMA of Superpave mixes generally can be contributed to the increased compactive effort by the Superpave gyratory compactor. This has led to the increased use of coarser asphalt mixes (gradations near the lower control points). However, the minimum VMA requirements in Superpave volumetric mix design for these coarse mixes are the same as those developed for the dense mixes designed by the Marshall method. Literature review has indicated that the rationale behind the minimum VMA requirement was to incorporate at least a minimum permissible asphalt content into the mix to ensure its durability. Studies have shown that asphalt mix durability is directly related to asphalt film thickness. Therefore, the minimum VMA should be based on the minimum desirable asphalt film thickness instead of on a minimum asphalt content because the latter will be different for mixes with different gradations. Mixes with coarse gradation (and, therefore, a low surface area) have difficulty meeting the minimum VMA requirement based on minimum asphalt content despite thick asphalt films. A rational approach based on a minimum asphalt film thickness has been proposed and validated. The film thickness approach represents a more direct, equitable, and appropriate method of ensuring asphalt mix durability, and it encompasses various mix gradations.

scholarly journals Application of Balanced Mix Design Methodology to Optimize Surface Mixes with High-RAP Content

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5638
Author(s):  
Fabrizio Meroni ◽  
Gerardo W. Flintsch ◽  
Brian K. Diefenderfer ◽  
Stacey D. Diefenderfer
Keyword(s):  
Asphalt Pavement ◽  
Design Procedure ◽  
Cost Savings ◽  
Field Performance ◽  
Mix Design ◽  
Potential Cost ◽  
Reclaimed Asphalt ◽  
Indirect Tensile ◽  
Environmental Savings ◽  
Virginia Department

The most common use of reclaimed asphalt pavement (RAP) is in the lower layers of a pavement structure, where it has been proven as a valid substitute for virgin materials. The use of RAP in surface mixes is more limited, since a major concern is that the high-RAP mixes may not perform as well as traditional mixes. To reduce risks or compromised performance, the use of RAP has commonly been controlled by specifications that limit the allowed amount of recycled material in the mixes. However, the ability to include greater quantities of RAP in the surface mix while maintaining a satisfying field performance would result in potential cost savings for the agencies and environmental savings for the public. The main purpose of this research was to produce highly recycled surface mixes capable of performing well in the field, verify the performance-based design procedure, and analyze the results. To produce the mixes, a balanced mix design (BMD) methodology was used and a comparison with traditional mixes, prepared in accordance with the requirements of the Virginia Department of Transportation’s volumetric mix design, was performed. Through the BMD procedure, which featured the indirect tensile cracking test for evaluating cracking resistance and the Asphalt Pavement Analyzer (APA) for evaluating rutting resistance, it was possible to obtain a highly recycled mix (45% RAP) capable of achieving a better overall laboratory performance than traditional mixes designed using volumetric constraints while resulting in a reduction in production cost.

scholarly journals Prediction of the optimum asphalt content using artificial neural networks

10.30544/579 ◽  
2021 ◽  
Author(s):  
Kareem Mohamed Mousa Othman ◽  
Hassan Abdelwahab
Keyword(s):  
Mix Design ◽  
Average Error ◽  
Aggregate Gradation ◽  
Asphalt Mixes ◽  
New Approach ◽  
Marshall Test ◽  
Asphalt Mix ◽  
Asphalt Content ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

The performance of the asphalt mix is significantly influenced by the optimum asphalt content (OAC). The asphalt content is responsible for coating the aggregate surface and filling the voids between the aggregate particles. Thus, the aggregate gradation has a significant influence on the required asphalt content. The Marshall design process is the most common method used for estimating the OAC, and this process is called the asphalt mix design. However, this method is time consuming, labor intensive, and its results are subjected to variations. Thus, this paper employs the artificial neural network (ANN) to estimate the OAC from the aggregate gradation for the two most common gradations used in asphalt mixes in Egypt (3D, 4C). Results show that the proposed ANN can predict the OAC with a coefficient of correlation of 0.98 and an average error of 0.026%. As a result, a new approach for the Marshall test can be adopted using results of the proposed ANN, and only three specimens, instead of fifteen, are prepared and tested for estimating the remaining parameters. This approach saves the time, effort, and resources required for estimating the OAC. Additionally, the ANN was validated with previously developed models, and the ANN shows promising results.

The influence of porous asphalt mix design on raveling resistance

2019 ◽  
Author(s):  
Marijana Cuculić ◽  
Aleksandra Deluka Tibljaš ◽  
Fabian Vasić ◽  
Ivana Pranjić
Keyword(s):  
Mix Design ◽  
Porous Asphalt ◽  
Asphalt Mix

Field Performance and Economic Analysis of Rehabilitated Pavement Sections with Engineered Stress Relief Course Interlayers

2019 ◽  
Vol 2673 (5) ◽  
pp. 351-364 ◽  
Author(s):  
Jhony Habbouche ◽  
Elie Y. Hajj ◽  
Murugaiyah Piratheepan ◽  
Peter E. Sebaaly ◽  
Nathan E. Morian
Keyword(s):  
Life Cycle ◽  
Cost Analysis ◽  
Life Cycle Cost ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Field Performance ◽  
Stress Relief ◽  
Mix Design ◽  
Reflective Cracking ◽  
Promising Technique

Previous studies showed that the use of a stress relief course asphalt concrete (AC) interlayer (fine-graded asphalt mixture) between an AC overlay and the milled AC surface is a promising technique to mitigate reflective cracking. A performance-based mix design specification for an engineered stress relief course (ESRC) AC interlayer was developed and implemented in Nevada on two field projects. The projects were completed in summer of 2015 and 2016 on a U.S. route (US95, Las Vegas) and a residential road (Hidden Valley, Reno) in Nevada, respectively. The performance evaluation of field-produced mixtures collected during construction showed good stability, and increased resistance to fatigue and reflective cracking that can be attributed to the increased asphalt binder content and the finer aggregate gradation, thus making ESRC a promising technique to mitigate reflective cracking. This was also supported by the distress survey data collected throughout the up-to-date service life of the projects. The pavements with ESRC interlayer showed excellent performance thus far (after 2 to 3 years) when compared with the control sections, as demonstrated with a much lower level of cracking reflected in the AC overlay. A simple life cycle cost analysis was performed based on the observed field distresses from each project. The cost analysis showed that even though the ESRC mixture has a higher initial cost of materials, the agency and user life cycle costs per lane mile are lower and resulted in an average cost saving of 23%. In summary, based on the findings from this study, interlayer AC mixes designed using the presented ESRC performance-based mix design method should be used in Nevada.

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