Study On Road Performance Of RET-SBR Composite Modified Bitumen And Its Mixture

In cold regions of China,Styrene-butadiene rubber(SBR)modified bitumen is widely used due to its excellent low temperature performance,but its high temperature performance and anti-ageing properties are deficient,so the scope of use is somewhat limited.Based on the above characteristics of SBR modified asphalt,this paper adds reactive terpolymer(RET)modifier to compound it to improve its high temperature stability and anti-ageing performance deficiencies,so that it can be used in hot summer and cold winter areas.Firstly,the method of physical blending is used to add reactive terpolymer(RET)and styrene-butadiene rubber(SBR)to the matrix bitumen for composite modification to make RET-SBR composite modified bitumen.The basic properties of the modified bitumen were studied by using the needle penetration,softening point,ductility test and rotational viscosity test;the influence of RET on the high temperature rheological properties of SBR modified bitumen was studied by temperature scanning test(TS)and multiple stress creep recovery test(MSCR);The effect of RET on the low-temperature properties of bitumen was studied by bending creep test.The effect of aging on the physical and rheological properties of asphalt was investigated by using the rotating film oven test(RTFOT)and the pressure aging test(PAV)to simulate the thermal and oxygen aging of asphalt.Fluorescence microscopy(FM)and infrared spectroscopy(FTIR)were used to explore the microscopic mechanism of RET modification.The optimal solutions of RET,SBR and oil-to-rock ratio were predicted by response surface method,and the high temperature,low temperature,water stability and fatigue resistance of RET-SBR composite modified asphalt mixes were evaluated.The results show that the reactive terpolymer can significantly improve the high temperature stability and ageing resistance of SBR asphalt;based on the prediction of the response surface method and experimental verification,the optimum modifier blending ratio of RET-SBR composite modified asphalt is 1.52% RET + 3.52% SBR asphalt mixture.The tests showed that after adding the reactive terpolymer,the high temperature rutting resistance and water stability of SBR modified asphalt were greatly improved,and its fatigue resistance was also improved to some extent.In summary,the addition of RET improves the high temperature stability and anti-aging performance of SBR modified bitumen,and RET-SBR composite modified bitumen and its mixtures have superior high temperature stability,low temperature crack resistance and aging resistance,and have the advantages of simple preparation process and low cost,which can be popularized and used in hot summer and cold winter areas.