Study On Viscosity-temperature Characteristic And Pavement Performance Of Warm Mixing Asphalt Mixtures

With the development of China transportation and the continuous improvement of the freeway network,freeway in cities and plains are gradually saturated,and the main battlefield has also shifted from plains to mountainous areas.Long-distance transportation of asphalt mixture and low temperature environment paving asphalt pavement temperature attenuation problem,it is difficult to ensure the compaction temperature and compaction quality.Simply increase the production temperature,also increase energy consumption and emission of exhaust dust,aggravate asphalt aging,affect the service life of asphalt pavement.Therefore,the paper studies the use of asphalt warm mix technology with warm mix to solve the problem of longdistance transportation of mixture away from the pavement site in the high-altitude mountainous area of Qinling Mountain and hot mixing station,which has significant technical and economic benefits.Based on the research project of Science and Technology Bureau of Ankang City of Shaanxi Province “Reconstruction Project of New G345 National Road to Ningshan-Shaanxi Road”,this paper uses 70# asphalt,self-developed viscosity-reducing warm mix additive ACMP(content of 4%,5%,6%)and surfactant Alube(content of 0.5%,0.7%,0.9%).The warm mix asphalt,the asphalt mixtures of AC-13 C and SMA-13 were prepared.Three indexes,Brinell viscosity tests were carried out,and the technical and road performance of warm mix asphalt were studied.The warm mix effect of the warm mix additives used was evaluated comprehensively by visco-temperature curve,variable temperature compaction method and variable temperature mixing method.Numerical simulation was carried out by ANSYS FLUENT to study the temperature attenuation law of long-time transportation of mixtures.The road performances of warm asphalt mixture were tested by laboratory tests.Finally,the paving technology of warm asphalt pavement is studied.The results show that:(1)the viscosity-reducing additive ACMP affected the technical properties of asphalt,increased the penetration and reduced the softening point and viscosity,but the surfactant Alube had no effect on these technical properties.(2)The two warm mix additives increased the compactness of the mixture and reduce the mixing viscosity.5% ACMP warm mixing asphalt or 0.7% warm mixing Alube asphalt mixtures reduced the construction temperature of asphalt mixtures by 17℃～24℃.(3)The temperature drop range of warm mix asphalt mixture after long time transportation was less than that of viscosity temperature curve,if warm mix technology is adopted,variable temperature compaction method and variable temperature mixing method,which still met the construction requirements;(4)Both ACMP and Alube had adverse effects on the high-temperature performance of asphalt mixture,but improved its low-temperature performance,and the improvement effect of ACMP was more significant.