Investigation On Road Performance And Durability Of Calcium Sulfate Whisker Asphalt Mixture

The high temperature stability,low temperature crack resistance and fatigue resistance of asphalt mixtures can be improved by adding fibers,but there are some shortcomings in the modification of asphalt mixtures with different commonly used road fibers.In the vast salt-rich areas of China,asphalt pavement materials have been eroded by salt for a long time,and their performance has deteriorated seriously.Among them,the research on durability of asphalt pavement under sulfate erosion environment is still in its infancy.Calcium sulfate whisker has dual characteristics of fiber and granular material,and has certain advantages and potential in improving road performance and durability of asphalt mixture.Calcium sulphate whisker can be used as raw material for gypsum production,which can realize waste utilization and has environmental protection effect.In this paper,AC-13 asphalt mixture is taken as the research object,and calcium sulfate whiskers with different dosages are added.The effects of calcium sulfate whiskers on high temperature stability,low temperature cracking resistance and water stability of asphalt mixture are studied through rutting test,low temperature bending test and freeze-thaw splitting test,and the optimum dosage of calcium sulfate whiskers is determined.The durability of calcium sulfate whisker asphalt mixture was studied through the Marshall stability test of vacuum saturated asphalt mixture under the condition of sodium sulfate solution erosion and the splitting strength test of asphalt mixture under the coupling action of sulfate erosion-freeze-thaw/dry-wet cycle.The results show that calcium sulfate whisker can effectively improve the high temperature stability,low temperature crack resistance and water stability of asphalt mixture,and the optimum content of calcium sulfate whisker is 0.4%.The addition of calcium sulfate whiskers can also improve the fatigue life of asphalt mixtures and reduce the corrosion degradation of asphalt mixtures by sulfate and freeze-thaw/dry-wet cycles.Calcium sulfate whisker disperses in asphalt mixture,plays a reinforcing and load transfer role,and improves the interface adhesion between asphalt and aggregate,which is the main reason for improving the durability of asphalt mixture.