Identify, initiate, and complete fundamental research on conventional and modified binders. Material characterization: (1) Understand, predict, and prevent moisture susceptibility.(2) Develop procedures, tests, and models that can accurately predict long-term pavement performance.(3) Understand asphalt composition and its relationship to pavement performance.(4) Construct and monitor pavement validation sites akin to the Strategic Highway Research Program (SHRP) specific pavement studies (SPS) six sites.
Research addresses five focus areas:
- Optimization of pavement performance.
- Advanced quality systems.
- Pavement surface characteristics.
- Technical capability building.
- Environmental stewardship.
This work has subsequently been repackaged in the following four areas:
- Determination of Moisture in Asphalt Binders and Mixes for hot-mix asphalts and warm-mix asphalts.
- Development of Rapid and Microbinder Characterization tools to assess environmental effects on performance.
- Characterization of Comingling of Virgin and Reclaimed Asphalt Pavement Material.
- Development of Asphalt Oxidation Model.
MoistureDeveloped small-scale separation methods to expand knowledge of molecular components that may be contributors to moisture-related premature roadway failures.Karl Fischer titration technique appears to be the most profitable approach of the various methods tried for ascertaining moisture content of asphalt binders.RapidDeveloped rheological instrumental technique for evaluating small quantities of binder at both high and low temperatures. This approach (4-mm parallel plate) has been found useful in characterizing asphalt emulsions.Developing methods for using Atomic Force Microscopy as a nano-rheometer. At present the nano-rheometer is capable of determining the rheological phase angle but not the moduli.Reclaimed Asphalt Pavement (RAP)/Warm-Mix Asphalt (WMA)Monitored existing validation sites (constructed under previous contract) and found significant differences in performance. OxidationDeveloped and validated rapid procedure for estimating pavement oxidation levels with depth using infrared spectroscopy on minute samplesDeveloped and applied Asphaltene Determinator Asphalt Aging Index Ratio (ADAIR) to track oxidative aging.