Performance Evaluation Of Straight-mixed SBS Modified Asphalt And Its Asphalt Mixture

At present,the application of modified asphalt is restricted by the process conditions of production,transportation and storage,and the quality is difficult to guarantee.The direct-mixing SBS modification method avoids the equipment limitation of on-site production of modified asphalt,does not need to consider the transportation and storage of modified asphalt,saves costs,and even eliminates the high temperature aging in the process of modified asphalt production,and solves the above problems.One of the technical measures of feasibility.In order to determine the suitable heating temperature and heating time of the direct-mixing SBS modifier,the microwave heating method was adopted,and the melting temperature and heating time were used as evaluation indexes.The asphalt mixture was determined by observing the melting condition of the direct-mixing SBS modifier.The technical parameters of the direct-mixing SBS modifier during mixing are proposed.When the heating temperature is 150? and the heating time is not less than 20 s,the direct-mixing SBS modifier furnace has the best effect.The direct-mixed SBS modified asphalt was prepared by "wet method",and the performance indexes of the PG system in the penetration system and the SHRP standard were tested.The modification effect of the direct-mixing SBS modifier on the asphalt was analyzed.The results show that with the increase of the amount of direct-mixing SBS modifier,the temperature sensitivity of asphalt improves,the viscosity of high temperature increases,and the ductility of low temperature increases.However,when the dosage exceeds 6%,the temperature sensitivity of asphalt increases.The recommended optimum amount of direct-mixing SBS modifier is 6%.In order to study the effect of direct-mixing SBS modifier on the performance of asphalt mixture,two common asphalt mixtures of asphalt mastic asphalt mixture(SMA-13)and continuous dense grade asphalt mixture(AC-13)were selected.Perform road performance test.According to the Marshall volume parameter,the laboratory production process of preparing SMA-13 and AC-13 modified asphalt mixture by direct mixing SBS modifier was proposed,which provided a test parameter for the production mix ratio and production mixratio verification.Through Marshall test,the optimal gradation and optimum asphalt dosage of SMA-13 and AC-13 asphalt mixture were determined respectively.Indoor rutting,low temperature bending,water stability,etc.were carried out on the straight-mixed SBS modified asphalt mixture.Road performance test research,compared with the commercial finished SBS modified asphalt mixture,the asphalt mixture prepared by the direct mixing method has basically no difference in road performance,and has a slight advantage in high temperature deformation resistance.The high-temperature accelerated loading rutting test was carried out to evaluate the durability of the direct-mixed SBS modified asphalt mixture by means of a 1/3-scale road surface accelerated loading tester that can realistically simulate the actual stress condition of the road surface.The results show that the SMA-13 direct mixing SBS modified asphalt mixture rudder depth is 4.8% lower than the commercial finished SBS modified asphalt mixture,and the AC-13 direct mixing SBS modified asphalt mixture is reduced by 18.2%.Good high temperature stability and long-term road performance.