Performance Based Evaluation of Asphalt Surface Treatment using Third Scale Model Mobile Loading Simulator

Abstract

This dissertation presents the research efforts to evaluate the characteristics of asphalt surface treatment (AST) performance including aggregate retention, bleeding, and skid performance using the third-scale Model Mobile Loading Simulator (MMLS3). A new test protocol is developed that uses the MMLS3 and incorporates the digital image processing technique and British Pendulum Test (BPT) for the performance evaluation of ASTs.

In this study, the new MMLS3 AST performance test method is applied to evaluate the effects of fines content, aggregate gradation, and aggregate type (i.e., granite vs. lightweight) on aggregate retention performance. It is confirmed that aggregate retention performance is improved as the fines content decreases and the gradation becomes more uniform. Moreover, it is found that the aggregate gradation factor plays a critical role in the aggregate retention performance regardless of the type of aggregate. This research also develops a performance-based uniformity coefficient as an AST performance indicator.

A methodology is developed to determine the optimum application rate based on AST performance in laboratory tests; this methodology is then extended to the field application. Based on the characteristics of AST performance determined by MMLS3 tests with various AST application rates, the AST design equation as a function of the voids at the loose aggregate state is developed.

This research also develops a correlation that converts skid resistance laboratory results to field results. The ability of the MMLS3 test to simulate the texture of ASTs in the field is confirmed by finding the same trends in skid resistance characteristics of the two aggregate types for both laboratory and field results.