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• Stiffness and relaxation modulus similarly declined with water severities. • Master curves of creep compliance moved up, but inversely did relaxation modulus. • A larger size of coarse aggregate skeleton reduced HMA's moisture sensitivity. • Asphalt showed different reaction mechanisms in different water environments. With the degraded service performance induced by the erosion of dynamic water pressure environment in summer, asphalt pavement has to subsequently overcome the challenge of low-temperature environment in winter. Considering the unique phenomenon of the gradual disintegration of asphalt mixtures' components, it is still a lack of systematic research on moisture damage induced by dynamic water pressure environment from the perspective of viscoelastic properties. This study adopted the bending beam rheometer (BBR) method to evaluate the influence of dynamic water pressure environment on viscoelastic mechanical performance for asphalt mixture. The results indicated that both creep stiffness modulus and relaxation modulus of asphalt mixture showed similar downward trends with the increase in severities of different water environments, while values of relaxation modulus were slightly smaller than that of creep stiffness modulus. Master curves of creep compliance gradually moved upward with the increase in severities of dynamic water pressure environments, while master curves of relaxation modulus inversely moved downward. Specially, master curves of both creep compliance and relaxation modulus exhibited irregular trends for the dynamic water pressure environment of 60 ℃ − 0.414 MPa, which implied that significant erosion had been brought into asphalt mixture. A relative larger size of coarse aggregate skeleton could improve the resistance of asphalt mixture to moisture damage. The positive effect on improving resistance of asphalt mixture to moisture damage induced by SBS modified asphalt binder was stronger than the negative effect induced by the gradation with a relatively small nominal maximum aggregate size (NMAS). Differences existed in the reaction mechanisms of different types of asphalt binder subjected to the erosion of different water environments. [ABSTRACT FROM AUTHOR]

• FAM's performance greatly affected the moisture sensitivity of HMA induced by dynamic water environment. • Short-term conditioning in a harsh dynamic water environment also exhibited a great erosion effect on asphalt materials. • Softening and emulsifying showed more obvious effects on asphalt binder during dynamic water conditioning. • HMA tended to exhibit more elasticity as the increase of environment severity. Moisture damage induced by dynamic pore water pressure commonly occurs in asphalt pavement located in regions with rich rainfall. This kind of moisture damage illustrates a special and quite different mechanism compared with that induced by static water immersion and freeze-thaw. Fine aggregate mixture (FAM) plays a vital role on the entire resistance of hot mix asphalt (HMA) to moisture damage. However, there is still a lack of systematic research on the evaluation of moisture sensitivity for both HMA and its components such as asphalt binder and FAM at the same scale. This study adopted the bending beam rheometer (BBR) method to assess moisture sensitivity for HMA and its components induced by dynamic water environment. The results indicated that the creep stiffness for both HMA and its components declined after being conditioned in dynamic water environment. FAM was quite easily eroded and its maximum decrease extent of creep stiffness could even up to 54.8%. In this case, it was clearly shown that the moisture sensitivity of HMA was greatly affected by its FAM component's performance. The erosion effect of short-term conditioning in a harsh dynamic water environment was comparable to that of long-term conditioning in a mild environment. Softening and emulsifying showed more obvious effects on both asphalt binder and FAM during dynamic water conditioning, which made them exhibit more viscosity. Specially, after the FAM component on the surface of a HMA sample being scoured away, the retained coarse aggregate skeleton made the entire HMA sample still remain a certain mechanical strength and anti-erosion ability. Based on the analysis of the indicator m/S , HMA showed viscous performance in a mild dynamic water environment but tended to exhibit more elasticity with the increase of environment severity. [ABSTRACT FROM AUTHOR]