## 1 Introduction  
Asphalt mixture has been widely used in the world as the main construction material for pavement because of the advantages including good mechanical strength, smooth ride, low noise, convenient construction and maintenance [1; 2; 3; 4; 5; 6; 7]. However, the increase of traffic and the damage from external environmental factors leads to all kinds of pavement diseases, which shorten the service life and increase the maintenance costs [8; 9; 10; 11; 12]. Among various pavement diseases, moisture damage is one of the main diseases of early failure of asphalt pavement as it accelerates or causes some typical pavement diseases such as rutting raveling and road surface settlement cracking [13; 14; 15; 16; 17; 18]. Especially in seasonally frozen regions, moisture damage is a very serious disease of asphalt pavement caused by the freeze-thaw cycle and dynamic pore water pressure. In the asphalt-aggregate system, the aggregate-bitumen interface cohesive and adhesive bond determine the mechanical properties of asphalt pavement. The loss of cohesion (strength) and stiffness of the asphalt film, and the failure of the adhesive bond between aggregate and asphalt in conjunction with the degradation or fracture of the aggregate were identified as the main mechanisms of moisture damage in the spring-thawing season [19; 20; 21]. In recent years, many researchers around the world made great efforts into exploring the moisture damage mechanism at the aggregate-bitumen interface through numerical calculations or laboratory tests [22; 23; 24]. [PERSON] et al. evaluated the moisture sensitivity of aggregate-bitumen bonds with moisture absorption, tensile strength, and failure surface examination. The results showed that the linear relationship between retained tensile strength and the square root of moisture uptake suggests that the water absorption process controls the degradation of the aggregate-bitumen bond [25]. [PERSON] et al. focused on suggesting general mechanisms to explain asphalt-aggregate bond behavior in the Dynamic Shear Rheometer (DSR) moisture damage test. The results indicated that shear-thickening and thixotropy can explain the reversible behavior, the increasing dropping trend in wet conditions in the mechanism of the colloidal system [26]. [PERSON] et al. evaluated the influence of material properties and loading conditions on the response of asphalt mixtures subjected to a moisture environment. The results suggested that the diffusion coefficient of the asphalt matrix and aggregates, and the aggregate-matrix interface bond strength, have the most influence on the moisture susceptibility of the materials [27]. [PERSON] et al. investigated the feasibility of the newly developed bitumen bond strength (BBS) test for moisture damage characterization. The results indicated that modification and moisture exposure time highly affect the bond strength of asphalt-aggregate systems [28]. In order to solve these problems and extend the service life of asphalt pavements, a lot of research has been conducted on new pavement materials. The prevention approaches of moisture damage mainly focus on increasing aggregate roughness and modified asphalt [29; 30; 31]. Among various prevention approaches, it is generally believed that modification of asphalt binders has achieved positive significance over the last few decades [32]. [PERSON] et al. determined the effect of additives, such as hydrated lime as well as elastomeric (SBS) and plastomeric (EVA) polymer modified bitumen (PMB) on the stripping potential and moisture susceptibility characteristics of hot mix asphalt. The results indicated that samples prepared with SBS PMB exhibited more resistance to water damage compared to samples prepared with EVA PMB [33]. [PERSON] et al. showed that crumb-rubber modified mixes exhibited lower temperature susceptibility and greater resistance to moisture damage compared to normal mixes [34]. [PERSON] et al.