Novel Method for Assessing Moisture Damage in Asphalt Mixtures

Abstract

Moisture damage is a major cause of early pavement deterioration and often accelerates other distresses such as rutting, fatigue cracking, and raveling. Water infiltrates into the pavement structure through the cracks and air voids and weakens the adhesive bond between the binder and the aggregates as well as the cohesive bond between the binder particles. Several tests have been adopted to test for moisture susceptibility, most commonly the Modified Lottman (AASHTO, T283) and the Hamburg Wheel Tracking Device (AASHTO, T32404), however, these tests correlate poorly with field results and do not properly replicate the conditions which a pavement structure experiences in the field. Also, the mechanism which determines the mode of failure due to moisture damage, being either adhesive or cohesive, remains largely not understood, and the research tackling this issue is very scarce. The objective of this study is to introduce a new testing procedure based on the pull-off approach and study the factors which influence the mode of failure of the samples, such as the asphalt film thickness and loading rate.