Study On Rheological Properties Of Low Damping Modified Asphalt

As people’s awareness of environmental protection and energy conservation continues to increase,governments around the world are striving to find ways to improve energy efficiency and achieve a low-carbon economic development model.Studies have shown that there is a strong relationship between tire rolling resistance and fuel consumption.When the rolling resistance is reduced by 15%-30%,the fuel consumption of the car can be reduced by 3%-6%.Moreover,dynamic internal heat generation of modified asphalt under vehicle load conditions is one of the key problems leading to the early damage of asphalt pavement.This paper attempts to develop low damping modified asphalt to reduce rolling resistance during vehicle driving,reduce endogenous heat,and solve fuel and Road damage and other issues.We draw on the research of low-resistance tires,reduce the internal frictional resistance of pavement materials by modifying asphalt,and introduce the loss factor tanδ value which characterizes the fuel consumption during the driving process of automobile tires into asphalt material,which is used to characterize the endogenous asphalt material.Thermal and mechanical losses.Check the database of the laboratory of the school and the research institute of the cooperative research institute,select four polymers with different molecular structures as modifiers,and prepare low-damping modified asphalt by the combination with SBS,with loss factor(tan δ)and complex modulus(G*).Preferred polymer modifiers have shown that the long-chain branched ester polymer J-4 can significantly reduce the tan δ of the SBS modified asphalt and increase the G*,which is mainly due to the reduction of the loss modulus of the material and the deformation of the asphalt.Or the internal friction heat is reduced,the lag loss caused by the material is smaller,and the heat generation inside the material is lower.It was found by endogenous heat test and rolling resistance test that low damping modifier can reduce the power loss and endogenous heat of SBS modified asphalt.The microstructure of the asphalt sample was analyzed.It was found that the low damping modifier acts to increase the swelling area of the SBS phase,which makes more light components in the asphalt fill the SBS phase,which can increase the modified asphalt.The elastic component reduces endogenous heat.Based on the preliminary test results,we selected J-4 as a low damping modifier to prepare modified asphalt with different dosage of low damping modifier.The low damping modification was determined by three indexes,loss factor and complex modulus.The optimum dosage of the agent is 1.8%.The modified asphalt was prepared according to the optimum dosage of low damping modifier of 1.8%.The effect of low damping modifier on the temperature sensitivity of asphalt was analyzed by the rotational viscosity test of asphalt.The research shows that the low damping modifier significantly reduces the SBS.The temperature coefficient and flow energy of the modified asphalt reduce the temperature sensitivity of the asphalt,which makes the asphalt have better construction workability.The effects of low damping modifier on the high temperature performance of SBS modified asphalt were analyzed by dynamic shear rheological test and multi-stress repeated creep test.The results show that low damping modifier significantly reduces the phase angle and loss factor of asphalt and improves The ratio of the elastic modulus in the asphalt reduces the viscous modulus ratio,and the rutting factor is significantly improved,indicating that the low damping modified leaching agent can greatly improve the high temperature rutting resistance of the asphalt.The low damping modifier can also significantly reduce the cumulative strain of SBS modified asphalt,increase its recovery rate,reduce the non-recoverable flexibility,improve the rutting resistance,and the higher the dosage,the better the high temperature performance of the asphalt.The low temperature performance was analyzed by low temperature trabecular bending test.The results show that the low damping modifier has no effect on the low temperature classification of SBS modified asphalt,and the internal stiffness modulus and m value are not obvious in the low temperature classification range.Finally,the two kinds of asphalt were mixed with the asphalt mixture according to the design grade.The performance of the low damping modifier on the performance of the asphalt mixture was analyzed by the performance test of the mixed material.The research shows that the low damping modifier can improve the asphalt mixture.High temperature resistance to rutting,but the low temperature crack resistance and water stability of the asphalt mixture can be changed little.