Study On Road Performance And Damage Characteristics Of Drainage Asphalt Mixture Under Water-Temperature Coupling

Compared with the ordinary dense graded asphalt pavement,the drainage asphalt pavement has the advantages of being able to quickly drain the road surface water,improve driving safety,and reduce noise.It is very suitable for rainy areas such as southern China.However,due to the large void ratio of the drainage asphalt pavement,the moisture in the pavement is also more likely to enter the pavement structure,making it more prone to damage.Therefore,in this paper,the PAC-13 drainage asphalt mixture is designed by using the high viscosity modified asphalt prepared by RST high viscosity modifier as the binder,and the water-temperature cycle damage test is designed to analyze the water-temperature coupling effect of the drainage asphalt mixture.Under the road performance changes and damage characteristics.In this paper,high-viscosity modified asphalts with different RST contents were prepared by heating and shearing.The penetration rates,ring and ball softening point test,5 ℃ ductility test and 60 ℃ dynamic viscosity test were used to study the different RST contents.The change of penetration,softening point,ductility and dynamic viscosity of high viscosity modified asphalt.With the increase of the content of the high viscosity modifier RST,the penetration of the modified asphalt becomes lower,while the softening point and the ductility at 5 ℃ increase,and the dynamic viscosity at 60 ℃ has been significantly improved.It is10% high-viscosity modified asphalt.The relationship between gradation and porosity is analyzed,and the drainage asphalt mixture that meets the required porosity is designed by the method of Marshall test through porosity measurement,leakage test,scattering test and Marshall stability test.The time-temperature curve is drawn according to the actual climatic conditions,the indoor test conditions of the water-temperature cycle damage of the drainage asphalt mixture are designed using the accumulated temperature principle,and the dynamic water action conditions are designed according to the actual precipitation conditions and driving loads.The high-temperature rutting test,indirect tensile test,and scattering test before and after the water-temperature coupling effect were carried out on four kinds of drainage asphalt mixtures with 0.3% wood fiber,0.1% polyester fiber,0.3% basalt fiber,and no fiber.Compared with the four-point bending fatigue test,the influence of fiber stabilizer on the road performance of drainage asphalt mixture was analyzed and compared.The results show that the addition of basalt fiber can significantly improve the high temperature stability and low temperature stability of drainage asphalt mixture.,Water stability and anti-fatigue performance,mixed with polyester fiber can enhance the water stability of drainage asphalt mixture,and the addition of wood fiber is the most obvious improvement in low temperature stability of drainage asphalt mixture.A split test was carried out on the test specimens of the drainage asphalt mixture after the action of dynamic water under different temperatures and pressures.It was found that as the temperature increased and the dynamic water pressure increased,the splitting strength of the drainage asphalt mixture decreased.The damage characteristics of drained asphalt mixture under water-temperature coupling were studied.The porosity measurement,split strength test and indirect tensile test of Marshall specimens after different water-temperature coupling damage cycles were analyzed.The relationship between the porosity,cleavage strength and stiffness modulus of the test piece and the number of water-temperature cycles was analyzed,and the improvement effect of the mixed basalt fiber on the resistance of the water-temperature cycle damage of the drainage asphalt mixture was analyzed.Based on the logistic method,the damage model of the drainage asphalt mixture was established,and the relationship between the damage degree and the speed of the drainage asphalt mixture with the number of water-temperature cycle damages was quantitatively analyzed.