Significance of Conditioning Parameters Affecting Distinction of Moisture Susceptible Asphalt

Significance of Conditioning Parameters Affecting Distinction of Moisture Susceptible Asphalt Concrete Mixtures in the Laboratory

Vivek Tandon, Muhammad Murshed Alam, Soheil Nazarian and Nalini Vemuri

Abstract

Premature failure of pavements due to stripping is a common problem faced by various highway agencies around the country. Researchers have developed various theories to explain the phenomenon of stripping in the asphalt concrete (AC) mixes. Various laboratory test methods have also been developed to identify the moisture susceptible AC mixes. However, none of them can consistently identify moisture susceptible mixes. The Environmental Conditioning System (ECS) was developed as a part of the Strategic Highway Research Program to address these deficiencies.

A sensitivity study was undertaken to understand the impact of various conditioning parameters specified in the ECS on the accuracy in identifying moisture susceptible AC mixes in the laboratory. Based on this study, a set of modifications has been suggested for the conditioning stages of the ECS. The modified conditioning parameters have been evaluated on materials with known properties. The results from this study are reported here. Even though this study was specifically performed for the ECS, the results may be useful in improving more established test methods such as the modified Lottman and the Hamburg Wheel Tester.