State of the Art Report on Moisture Sensitivity Test Methods for Bituminous Pavement Materials

ABSTRACT The findings of an extensive literature review on bitumen and asphalt mixture moisture sensitivity test methods are presented in the paper. One of the primary factors affecting the durability of bituminous paving mixtures (assuming they are constructed correctly) is moisture damage. Water damage is generally manifested as a loss of cohesion in the mixture and/or loss of adhesion between the bitumen and aggregate interface (stripping). Water sensitivity tests are generally performed on either loose coated aggregate or on compacted mixtures with the conditioning processes attempting to simulate field exposure conditions. Usually the tests consist of a conditioning and evaluation phase, with the evaluation of the ‘conditioned’ specimens being either visual or mechanical. The most commonly used moisture conditioning procedure is the Lottman method or one of its various derivatives. An essential element of these conditioning procedures is the saturation of asphalt mixture specimens by submerging them in water and applying a partial vacuum. Of the various methods that incorporate the effect of traffic, the immersion wheel tracker and the Hamburg wheel-tracking device tend to be the most popular.