Evaluation of Three Federal Highway Administration Targeted Overlay Pavement Solutions for Asphalt Pavements Based on Their Performances and Potential to Increase Pavement Service Life

Abstract

The Federal Highway Administration Targeted Overlay Pavement Solutions (TOPS) program presents innovative overlay solutions for both asphalt and concrete pavements. The objective of this study was to conduct a comparative evaluation of three TOPS types for asphalt pavements, namely, Asphalt Rubber Gap-Graded, Stone Matrix Asphalt and High-Performance Thin Overlay as regards performance, how they extend pavement service life, and whether they can be used interchangeably. Asphalt binders from two sources were used in each of these three TOPS types, thus, providing a total of six TOPS mixtures. All TOPS passed the mixture performance tests where the test had a State Transportation Agency (STA) specified or a preliminary criterion, and the test results indicated that all three TOPS types can be used interchangeably. More specifically, all six TOPS mixtures met the Massachusetts Department of Transportation’s TOPS pilot specification criteria for rutting, moisture damage, and intermediate-temperature cracking. They also passed the mixture performance tests for reflective cracking and raveling based on criteria established by other STAs. AASHTOWare® Pavement Mechanistic-Empirical Design predictive models for bottom-up fatigue cracking indicated that 2 in. of a TOPS mixture placed on an existing in-service pavement can extend pavement service life between 11.2 and 14 years depending on the type of TOPS and source of binder. The maximum difference in service life between the six TOPS was slightly less than 3 years, although most of them were within 2 years of each other. Furthermore, none of the three TOPS types could be chosen to be the best TOPS.