Study On The Cracking Characteristics Of Warm Mixed Rubber Powder Asphalt Mixture After Aging Under Repeated Loading

The good road performance of rubber-powder modified asphalt mixture has been generally recognized,but the problems of high viscosity and construction temperature seriously hinder the promotion of rubber-powder modified asphalt pavement.The application of the Warm-mix technology can reduce the construction temperature,but whether the road performance of the rubber powder modified asphalt mixture will decrease after the Warm-mix is still uncertain.The light?oxygen?heat and other effects will make asphalt pavement aging,reducing the anti-cracking performance of asphalt mixture and increasing the damage of vehicle load on the pavement.Digital image correlation technology(DIC)is a non-contact optical measurement method,which is suitable for deformation measurement of asphalt mixture.The measurement result is of high accuracy.This paper takes 60 mesh Warm-mix rubber powder modified asphalt mixture(WMA)and 60 mesh Hot-mix rubber powder modified asphalt mixture(HMA)as the research object.Based on digital image correlation technique,it is take three point bending repeated loading test to research the effect of aging on the influence of WMA and HMA cracking characteristics before or after ultraviolet and thermal aging.First of all,based on DIC technology analyzes the advance in the process of reloading incision semicircle whole displacement and the strain of the specimen and determines the crack point horizontal strain Exx as the index of asphalt mixture cracking characteristics.It is take the curve of Exx along with loading frequency to study the influence of cracking characteristics on WMA and HMA through ultraviolet and thermal aging.Then,the damage of asphalt mixture is characterized by Exx,and the influence of ultraviolet aging and thermal aging on the damage characteristics of WMA and HMA is studied through the change curve of damage factors with The Times of loading.Finally,based on the damage threshold theory,the effects of UV aging and Thermal aging on the cracking characteristics of WMA and HMA are studied through fracture energy density and creep strain energy density.The results show that the loading times,fracture energy density and creep strain energy density of WMA and HMA specimens all decrease after UV and Thermal aging.Compared with thermal aging,the damage rate of WMA and HMA increase significantly after uv aging,that is,uv aging has a greater impact on WMA and HMA damage.Compared with HMA,the loading times?damage factors?fracture energy density and creep strain energy density of WMA before and after thermal aging and ultraviolet aging have smaller changes than HMA,indicating that the anti-aging performance of WMA is better than that of HMA.