## 1 Introduction  
Asphalt binder has been used for many years in paving and roofing constructions because of its great viscoelastic properties [1]. However, with the influence of traffic loading and environmental conditions, the relaxation capability and flexibility of asphalt mixtures gradually decline resulting in more ageing and lower cracking resistance, and this phenomenon is more obvious for virgin asphalt or reclaimed asphalt. To alleviate this problem, some additive agents were selected to be added to asphalt binders as modifiers to improve the mechanical and rheological abilities of asphalt [2]. There are different types of modifiers such as polymers, minerals, acids, etc., but among them, the styrene-butadiene rubber (SBR) has shown a great potential to increase the thermal cracking resistance of virgin binder. [PERSON] et al. found that SBR modified asphalt could significantly improve the viscosity and ductility of virgin asphalt, in addition to enhance the cracking resistance of asphalt mixture [3]. However, SBR modified asphalt is more prone to aging due to its butadiene-rich structure. Moreover, SBR-modified asphalt and asphalt mixture were susceptible to high-temperature damage because of the modification method, which results in poor high-temperature stability and compatibility [4]. Therefore, in order to obtain a comprehensive performance, as well as the high stability of asphalt binder, it is necessary to investigate more effective additives in combination with SBR. The self-healing capability of asphalt has been investigated in several researches. It has been proved that self-healing has the potential to prolong the serviceability of asphalt concrete [5; 6; 7]. In general, the research of self-healing mechanism is still a hot topic. Several methods and models were used to fully understand the self-healing phenomenon, such as molecular diffusion healing model, surface energy healing model, capillary flow healing model [8]. Based on the research by [PERSON] et al. [9], the self-healing of asphalt materials was influenced by many factors, including rest time, temperature, binder properties, damage level, and material modifications. The healing process at the ambient temperature is very slow, and it is difficult to healing the micro cracks and other damages during the service life of asphalt concrete. Therefore, various external intervention methods were performed to speed up the healing process, such as heating the asphalt concrete by electromagnetic induction [10; 11], microwave induction [12; 13], and mixing microcapsules containing healing agent [14; 15] in asphalt concrete. In addition, the concept of self-healing comes from the natural and biological phenomena, which can help the organisms recover, repair the cracks, and finally lengthen the span of life. Nowadays, some novel self-healing materials including hollow fibers, nanoparticles, and ionomers were used in functional composite materials (such as polymer and asphalt) [16]. The ionomer poly(ethylene-\(co\)-methacrylic) acid (EMAA) has shown a great potential for the self-healing reinforcement of asphalt materials. [PERSON] et al. [17] studied self-healing efficiency and mechanism of EMA in epoxy resin and found that EMA has different healing process than the other repairable polymer systems. [PERSON] et al. [18] reported that the cracks in carbon fiber-epoxy laminates can achieve self-healing by using EMAA fibers or particles. In addition, the self-healing efficiency by using EMAA is higher than using the microcapsule method. [PERSON] et al. [19] confirmed that adding EMAA in carbon-epoxy laminates is an effective way to prevent the fatigue and static cracks. In another study, [PERSON] et al. [20] investigated the compatibilizing ability of EMAA on polyvinyl chloride (PVC)/polyppropylene (PP) composite materials. The results showed that EMAA had better compatibilizing ability than ethylene-vinyl acetate copolymer (EVA) and low-density polyethylene (LDPE).