Research On Warm Mix Composite Modified High Viscosity Asphalt Ultra-thin Overlay Technology

High-viscosity asphalt has excellent high and low temperature performance and is widely used in ultra-thin overlay pavement structure.Its construction mixing temperature is much higher than that of ordinary polymer modified asphalt.At the same time,it is accompanied by problems such as large energy consumption and serious pollution.This paper uses warm mix modification to study the ultra-thin overlay technology of warm mix composite modified high-viscosity asphalt.Firstly,by analyzing the existing warm mix technology,it is determined that the material composition type is four kinds of compatibilizer,resin,saturated alkane polymer and surfactant,which are compounded with SBS modified asphalt.Then,the types of various materials are determined by the influence of single component on SBS modified asphalt.The proportion of each material is determined by orthogonal test and range analysis,and the ductility agent is added for optimization.Finally,two kinds of warm mix composite modified high viscosity asphalt are recommended and recorded as ZHVA-1and ZHVA-2.The high and low temperature performance of SBS modified asphalt,ZHVA-1,ZHVA-2 and finished LWK high viscosity asphalt was studied.The high and low temperature performance and deformation resistance were evaluated by three indexes,60 °C dynamic viscosity and elastic recovery.It was found that the three high viscosity asphalts all met the requirements of the specification,and the dynamic viscosity at 60 °C was ZHVA-1 > LWK > ZHVA-2 > SBS modified asphalt,indicating that ZHVA-1 had good high temperature performance,while the ductility agent B had an adverse effect on the high temperature performance of asphalt.The viscosity temperature index VTS is used to evaluate the temperature sensitivity of high viscosity modified asphalt.The temperature sensitivity of the four asphalts from high to low is : ZHVA-1,ZHVA-2,LWK,SBS modified asphalt.Infrared spectroscopy analysis showed that only physical blending occurred in the three high-viscosity asphalts,and no chemical reaction occurred.The rheological properties of four kinds of asphalt were studied.Firstly,the timetemperature equivalent master curve was constructed by frequency scanning.The results showed that the high temperature performance of three kinds of high viscosity asphalt was better than that of SBS modified asphalt.The Carreau model was used to fit the zero shear viscosity of four kinds of asphalt at 60 °C,and the order was ZHVA-1 > LWK >ZHVA-2 > SBS modified asphalt.The zero shear viscosity of ZHVA-1 and ZHVA-2 was175294.3 Pa·s and 158457.3 Pa·s,respectively.The temperature scanning results show that the high temperature performance and fatigue resistance of the three high viscosity asphalts are better than those of SBS modified asphalt.The results show that the deformation recovery ability and anti-deformation ability of ZHAV-1 and LWK are at the same level,and the deformation recovery ability and anti-deformation ability of ZHVA-2 decrease,which are higher than those of SBS modified asphaltSMA-10 was used to evaluate the road performance of four kinds of asphalt.The compaction temperature of ZHVA-1 and ZHVA-2 high viscosity asphalt was determined by cooling compaction method,which was 25 °C and 30 °C lower than that of SBS modified asphalt.The road performance of four kinds of asphalt was evaluated by rutting test,trabecular bending test and freeze-thaw splitting test.The test results showed that the high and low temperature performance of ZHVA-1 warm mix composite modified high viscosity asphalt mixture was similar to that of LWK high viscosity modified asphalt mixture.The high and low temperature performance of ZHVA-2 high viscosity asphalt mixture decreased,but it was still higher than that of SBS modified.