# Performance and Mechanism of Asphalt Modified by Butadiene-Rubber
## 1 Introduction
From the above, the rock asphalt can fully exert its excellent high-temperature performance, and enhanced the anti-aging property after mixing with other modified asphalt. The SBR can also provide good low-temperature performance for the asphalt binders modified by other materials. Besides, compared with the widely used SBS modified asphalt, the superior processability, economic efficiency, and environmental benefits of rock asphalt and SBR can make them appropriate additives to enhance the performance of base asphalt [15; 16; 17; 18]. Some researchers have verified the expedience of other natural asphalts and SBR as compound modified materials in asphalt, including gilsonite and Lack asphalt. [PERSON] et al. [19] found that the addition of SBR powder to the gilsonite improved the low-temperature deformation capacity by decreasing the stiffness values of asphalt binder with opposed impact on the m-value (i.e., the change rate in stiffness to time). The results suggested that the temperature sensitivity and anti-deformation capacity at high temperatures improved after the compound modification. [PERSON] et al. [20] investigated the compound modified effects of SBR and Trinidad Lack Asphal on the base asphalt. The results demonstrated that compound modified asphalts have favorable low-temperature deformation property and high-temperature performance. Given that the above studies have achieved good results, the Buton-rock asphalt (BRA) and SBR were selected as modifying agents to mix with the matrix asphalt in the present study. The purpose is to combine the anti-crack capacity of SBR at low temperatures and the anti-deformation capacity at high temperatures and anti-aging capacity of BRA modified asphalt. Furthermore, two types of SBR, powder SBR and latex SBR, are commonly used as asphalt modifiers. [PERSON] et al. [21] added latex SBR to 90 PG base asphalt to improve the low-temperature and anti-aging performance. [PERSON] et al. [22] studied the difference between powder SBR and latex SBR on the performance of base asphalt. However, few studies have focused on the difference between powder SBR and latex SBR on the performance of BRA modified asphalt, not just base asphalt. For obtaining the compound modified asphalt with better properties, two types of BRA modified asphalt containing powder SBR or latex SBR were compared in this study. Therefore, powder SBR A and latex SBR B were mixed with BRA modified asphalt to prepare BRA-SBR modified asphalt in the high-speed shear equipment. The dosages of SBR were 0%, 2%, 4%, 6%, and 8%. The examination of the high-temperature performance of compound modified asphalt was based on the rotational viscometer (RV) and dynamic shear rheometer (DSR) tests. The bending beam rheometer (BBR) test was adopted to compare the difference of low-temperature performance of the compound modified asphalt, both BRA-SBR A and BRA-SBR B modified asphalt. The short-term aging capacity was evaluated by the rheological performance of un-aged and RTFOT-aged asphalts. Meanwhile, the modification mechanism of BRA modified asphalt before and after adding SBR was revealed by the Fourier transform infrared spectroscopy and scanning electron microscopy test.