## 1 Introduction  
With the large-scale construction of asphalt pavement, the demand for petroleum-based asphalt is increasing [1, 2]. Considering the heavy traffic load and changing temperatures, asphalt pavement is prone to various problems, such as rutting, fatigue, and thermal cracking [3, 4, 5]. To address these issues and enhance the engineering properties of asphalt binders, modifications are necessary. In the realm of green technology, utilizing crumb rubber (CR) [6]-modified asphalt [7] offers a promising solution. This approach not only helps in consuming vast quantities of waste tires but also contributes to reducing carbon emissions during the construction process [8, 9]. When integrated into the asphalt, the rubber particles absorb light components, causing them to expand significantly, which in turn improves the asphalt's high-temperature performance. Furthermore, mixtures with rubber-modified adhesives are reported to reduce traffic noise [10], reduce maintenance costs [11], and enhance wear resistance, skid resistance, and rutting and cracking resistance [12]. However, integratingcrumb rubber into asphalt faces significant challenges due to the inert characteristics of CR's surface, which hinders its effective mixing with the asphalt binder [13]. This causes incompatibility and poor adhesion between the CR and the binder coupled with a compromised storage stability of the asphalt-rubber mixture [14; 15]. Research efforts have led to the development of a pre-desulfurization process for CR, resulting in desulfurized rubber powder (DCR), which destroys the CR cross-link and reduces its molecular weight or controls its internal network structure to improve the compatibility of the CR and native asphalt [14; 16]. The desulfurization process destroys the grid structure of the rubber powder, reduces the size and number of the rubber particles, and makes the desulfurized rubber powder swell more easily [16]. [PERSON] et al. [17] found that DCR expanded more thoroughly than CR in matrix bitumen. Although the asphalt characteristics are enhanced with the increase in the DCR content, an excess amount of rubber cannot achieve a better performance improvement, and the adhesion between the DCR and binder will be reduced, leading to a series of problems such as an increased segregation degree, high viscosity, and difficult construction problems. [PERSON] et al. [18] found that the optimal amount of DCR with a satisfactory mixture performance was 20%. This greatly limits the consumption ability of waste tire rubber powder and the further control of the cost of rubber asphalt. In parallel, the exploration of biomaterials as asphalt modifiers is gaining traction due to their affordability, renewability, and environmental benefits. Bio-oils from sources like waste cooking oil, castor oil, and soybean oil have shown potential as effective asphalt enhancers [19; 20; 21], which could potentially lead to a better dispersion of the crumb rubber within the asphalt. However, directly adding bio-oil to asphalt may reduce the viscosity of the asphalt mixture, potentially compromising its stability. In line with molecular design principles, crumb rubber, after being activated through grafting with acrylamide and utilized as an asphalt binder modifier, showed a reduction in the difference in softening points. However, the overall effect of this modification was found to be limited [22]. This study introduces an innovative approach involving the surface chemical grafting of an amidated epoxy soybean oil agent (ESO/TETA), aimed at improving asphalt's performance across different temperatures and enhancing its storage stability. This development represents a step towards sustainable road construction, offering the dual benefits of reducing maintenance costs and extending the lifespan of road surfaces. It is expected to provide a new and environmentally friendly pavement material for the road engineering field, reduce maintenance costs, extend the service life of pavement, and promote the realization of sustainable road construction.