Study On Performances Of Warm Mixing Rubber Modified Asphalt Mixture In Cold Regions

In order to improve the performance of asphalt pavement in permafrost area and the workability of rubber asphalt mixture,and further prolong the construction period,this paper has studied the mix design method and industrial production parameters of warm-mix rubber modified asphalt mixture.The optimum mixing ratio was then determined.Through rutting test,low temperature bending test,freeze-thaw splitting test and accelerated loading test,the performances of three warm-mixing rubber modified asphalt mixture consisting of Evotherm DAT,Sasobit and Aspha-min were compared.There were also compared with hot-mixing rubber modified asphalt mixture and SBS modified asphalt mixture.The results show that the suitable rubber powder content of the warm mixing rubber modified asphalt in cold area is 22%.Equal voidage method is recommended in order to determine the paving and rolling temperature of the warm mixing rubber powder modified asphalt mixture.Moreover,un der the mixing condition with the same temperature,the workability of the warm mixing rubber asphalt mixture is better than the hot mix rubber asphalt mixture.Compared to hot mixing rubber asphalt mixture,the rut dynamic stability,immersion stability,freeze-thaw splitting strength of warm mixing rubber asphalt mixture are improved.However,the maximum flexural strength through low temperature bend test has decreased.These results explain that the warm mixed agent can improve the high temperature performance and water stability of rubber asphalt mixture,but can cause adverse effects on the low temperature performance.The results of accelerated loading test show that Evotherm-DTA warm mixed agent has the best fatigue resistance.Engineering practice indicates that Evotherm DAT warm mixed agent can extend the construction period of rubber modified asphalt mixture by 1-2 months.Thus,it reduces the cost of the construction machinery and labor.At the same time,the feeding radius of a single mixing plan t are broaden and it helps to guaranteeing the construction quality.Thus,warm mixed rubber modified asphalt mixture has the promising application in the cold region.