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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

Overview

 

Research and Development (R&D) Project Sites

Project Information
Project ID:   FHWA-PROJ-03-0001
Project Name:   Development of Performance-Based Specification for Asphalt Binders: Fatigue Characterization
Project Status:   Completed
Start Date:  January 1, 2003
End Date:  June 30, 2010
Contact Information
Last Name:  Gibson
First Name:  Nelson H
Telephone:  202-493-3073
E-mail:  nelson.gibson@dot.gov
Office:   Office of Infrastructure Research and Development
Team:   Pavement Materials Team [HRDI-10]
Program:   Innovative Pavement Research and Deployment
Laboratory:   Pavement Testing Facility
Project detail
Roadmap/Focus area(s):   Infrastructure Research and Technology Strategic Plan and Roadmap
Project Description:   Test pavements were constructed with the primary variable being the binder type. Full-scale rutting and cracking performance were collected and compared to various candidate binder tests to identify the most discriminating element to replace the current specification for asphalt fatigue cracking and rutting.
Goals:   The primary objective of this full-scale accelerated pavement testing was to evaluate the performance of unmodified and polymer-modified asphalt binders, and to recommend improved specification tests over existing Superpave (SUperior PERforming Asphalt PAVEments) performance-grading methodologies.
Product Type:   Research report
Test Methodology:   Full-scale accelerated pavement testing with laboratory materials characterization.
Partners:   Federal Highway Administration: Office of Research, Development, and Technology - Office of Infrastructure Research and Development; Role(s): Technical
Expected Benefits:   The expected benefit is more durable, longer-lasting asphalt pavements.
Deliverables: Name: Final report: "Full-Scale Accelerated Performance Testing for Superpave and Structural Validation: Transportation Pooled Fund Study TPF-5(019) and SPR-2(174) Accelerated Pavement Testing of Crumb Rubber Modified Asphalt Pavements"
Product Type(s): Research report
Description: This final report provides the comprehensive findings from two Transportation Pooled Fund (TPF) research projects: TPF-5(019) Full-Scale Accelerated Performance Testing for Superpave (SUperior PERforming Asphalt PAVEments) and Structural Validation and SPR-2(174) Accelerated Pavement Testing of Crumb Rubber Modified Asphalt Pavements. The research identified candidate purchase specification tests for asphalt binder that better discriminate expected fatigue cracking and rutting performance than current Superpave tests. Full-scale accelerated pavement testing and laboratory characterization tests on mixtures and binders provided the basis for the recommendations.The report documents a historical review of the development of asphalt binder performance specifications, experimental design, test pavement construction and performance, and statistical methodology to rank and identify the strongest candidates, and all pertinent laboratory characterization of binders and mixtures that supplemented the recommendations. The research also provided a detailed case study of pavement evaluation using a falling weight deflectometer and objective means to evaluate two emerging technologies: the Asphalt Mixture Performance Tester and the Mechanistic-Empirical Pavement Design Guide.
Publication URL(s):
http://www.fhwa.dot.gov/publications/research/infrastructure/pavements/11045/index.cfm
Project Findings:   Two fatigue cracking specification tests were identified as being more capable thanothers: binder yield energy and critical tip opening displacement. Two rutting specification tests that quantify irrecoverable deformations exhibited the best strength to capture rutting: multiple stress creep, and recovery and oscillatory-based nonrecoverable stiffness. Based on the full-scale performance and laboratory tests, crumb rubber (recycled tires) modified asphalt (Arizona wet process) was shown to significantly slow or stop the growth of fatigue cracks in a composite asphalt pavementstructure. A hybrid technique to modify asphalt with a combination of crumb rubber and conventional polymers (terminally blended) exhibited good fatigue cracking resistance relative to the control binder without the special handling procedures needed for some crumb rubber modified asphalts. Also, a simple addition of polyester fibers-to-asphalt mix was shown to have high resistance to fatigue cracking without the use of polymer modification. The research study also quantified the capabilities of the National Cooperative Highway Research Program’s mechanistic-empirical pavement design and analysis methodologies to predict rutting and fatigue cracking of modified asphalts that were not captured in the calibration data from the Long-Term Pavement Performance program. Falling weight deflectometer, multidepth deflectometer, and strain gauge instrumentation were used to measure pavement response. The results illustrated that the globally calibrated mechanistic-empirical performance models could differentiate between structural asphalt thickness but had difficulty differentiating modified from unmodified asphalt binder performance. Nonetheless, the mechanistic-empirical performance ranking and predictions were enhanced and improved using mixture-specific performance tests currently being implemented using the Asphalt Mix Performance Tester.
FHWA Topics:   Roads and Bridges--Design
TRT Terms:   Testing
Fatigue cracking
Rutting
Superpave
Pavement Design
Falling Weight Deflectometers
Mechanistic Design
Performance Tests
Research
Infrastructure
Pavements
Bituminous Binders
FHWA Disciplines:   Pavement and Materials
Subject Areas:   Design
Highways
Research
Pavements

 

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