## 1 Introduction  
In general, pothole problems can be defined as bowl-shaped holes in the surface of asphalt pavement, and their existence is averse to traffic safety and rideability of roads [1, 2]. Potholes often develop from heavy traffic loads in adverse weather, especially in winter or rainy seasons [3, 4]. Water is the critical factor in aggravating the distress of potholes, which can seep into the internal pavement through low-temperature cracking due to deformation or alligator cracking due to fatigue [5, 6]. Finally, the water damage leads to structural failure and the hollowing out of the base or subgrade. Furthermore, low temperatures and water have negative effects on the patching process and durability of pothole repairs [7, 8]. Thus, timely and durable repairs are essential in order to prevent further deterioration. The most common distresses of pothole patches include shoving, raveling, dishing, bleeding, edge disintegration, stripping, and alligator cracking. These distresses are closely related to the quality of binder and the rationality of gradation [5, 8, 9]. According to material composition and construction technology, patching materials can be divided into three groups: hot-mixed and hot-placed patching mixtures; hot-mixed and cold-placed patching mixtures; and cold-mixed and cold-placed patching mixtures [10, 11, 12, 13]. The last two using cutback asphalt and emulsified asphalt as their binder are preferred in winter, as they do not require heating [14, 15, 16]. However, these two kinds of patching mixtures have rigid requirements for the temperature during construction [11]. There are continuous gradation and gap-graded gradations in cold mixtures, and continuous gradation has a superior pavement performance but has poorer workability, as compared with gap graded gradation. [3]. Thus, the selection of the binder and gradation has a significant impact to the design of patching materials. The cold mixtures solidify gradually with the increase of storage time due to the volatilization of the dilute and curing of the additive in the binder, which has an adverse effect on the workability of the cold mixtures during the construction process. Ideally, microcapsule technology can effectively solve this problem. A microcapsule is a type of micro-container, with an outer shell wall made of natural or synthetic polymer material [14; 17; 18]. It effectively inhibits the reaction of the active material with the external environmental factors and reduces the diffusion and evaporation of core materials into the environment [19; 20]. In recent studies, [PERSON] et al. controlled the cement hydration reaction by encapsulating the additive in an effort to reduce the cracking caused by hydration heat of concrete, during extreme weather [21]. [PERSON] et al. developed the self-repairing concrete by using epoxy-containing silica microcapsules and amine-functionalized nanosilica [22]. Then, [PERSON] et al. found that microcapsules with toluene diisocyanate (TDI) used as the core and paraffin used as the shell, could be prepared through the melting condensation method allowing for self-healing concrete. The compressive strength of mortar can be increased by 28.2% [23]. [PERSON] et al. developed an aided regeneration system of aged asphalt binder based on the microcapsule technology, which can prolong the service life of the asphalt pavement. Microcapsules containing regenerants were prepared by in-situ polymerization. The capsule shell was made of melamine-urea-formaldehyde (MUF) resin [24]. The main objective of this paper is to propose new polymer modified using dense graded patching materials (i.e., polymer modified asphalt and dense graded (DG) of aggregates (PADG) mixtures). This is based on microcapsule technique and polymer reinforcement, and verifies the practicability of PADG mixtures allowing for timely and durable pothole repairs in winter-rainy conditions.