Study On Mix Proportion Design And Pavement Performance Of Permeable Asphalt Pavement Mixture

Permeable asphalt pavement refers to the asphalt mixture surface with more than 18%air voidage and inside has function of permeability and drainage,which can quickly drain the water off the road surface and improve the safety and driving comfort of the public in rainy days.Rainwater can penetrate into the soil through the voids,nourish the plants on the surface and improve the ecological environment of the city.At the same time,groundwater can be replenished to improve the recycling utilization rate of water resources,alleviate the shortage of water resources in cities,improve the drainage efficiency of urban drainage system during heavy rain,and reduce the probability of waterlogging in cities during heavy rain.So,in order to improve the urban ecological environment,improve urban drainage capacity,and facilitate the construction of "sponge city",this paper has carried out a study on the mix proportion design of permeable asphalt pavement mixture and its pavement performance.Based on the investigation of permeable asphalt pavement that has been put into use in our country,and combined with the current codes of our country about permeable asphalt pavement and the climate characteristics of Jiangxi province,this paper puts forward the selection standards of raw materials of permeable asphalt pavement mixture that suitable for Jiangxi province.And designed the test method to measure the connected void fraction of permeable asphalt mixture,studied and analyzed the relationship between the void fraction and the connected void fraction,and the relationship between the void fraction and the permeability coefficient.Through the method of definite integral,obtained the design formula of the target porosity of permeable asphalt pavement.High viscosity modified asphalt A and high viscosity modified asphalt B were prepared by adding 6%,9%,12% and 15% HVA high viscosity modifier respectively into grade A 70# road petroleum asphalt and SBS modified asphalt(I-D),carried out the three major indexes of asphalt test and 60℃ dynamic viscosity test,it is found that with the increase of HVA content,the needle penetration of high viscosity modified asphalt A and B are decreased,and their softening point,ductility and dynamic viscosity at 60 ℃ are increased,the results show that HVA high viscosity modifier can improve the viscosity,high temperature resistance and low temperature stability of asphalt.The optimal content of HVA high viscosity modifier is 15% in grade A 70# road petroleum asphalt,and that is9% in SBS modified asphalt(I-D).The high viscosity modified asphalt A and high viscosity modified asphalt B were respectively used to design the mix proportion of PAC-13,getting the optimal asphalt-aggregate ratio of PAC-13(A)is 4.9%,and the optimal asphalt-aggregate ratio of PAC-13(B)is 4.8%.Carried out water stability test and high temperature stability test to them,the results show that PAC-13(B)has better performance.Calculated the raw material cost of PAC-13(A),PAC-13(B)and AC-13 C,it is found that the raw material cost of PAC-13(A)is 1.38 times that of AC-13 C,and the raw material cost of PAC-13(B)is 1.21 times that of AC-13 C.This paper selected three different permeable asphalt mixtures of without fiber,adding polyester fiber and adding basalt fiber to study the pavement performance.Carried out high-temperature rutting test,freeze-thaw splitting test,low-temperature bending test and four-point bending fatigue life test to three kinds PAC-13 of adding different fibers,the results show that polyester fiber and basalt fiber can effectively improve the high temperature stability,water stability,low temperature crack resistance and fatigue resistance of permeable asphalt mixture.Carried out Permeability test to three kinds PAC-13 of adding different fibers,it is found that polyester fiber and basalt fiber can decrease the voids and permeability performance of permeable asphalt mixture.The raw material cost of three kinds PAC-13 of adding different fibers was calculated and analyzed,it is found that the raw material cost of PAC-13 of adding polyester fiber is 1.03 times that of PAC-13 of without fiber,and the raw material cost of PAC-13 of adding basalt fiber is 1.09 times that of PAC-13 of without fiber.This paper carried out production mix proportion design of PAC-13,constructed a 300 meter long test section of PAC-13,presented construction technology of permeable asphalt pavement,and tested performance of test section,it is found that all the indexes of the test section of permeable asphalt pavement meet the requirements of the code,and the test section have good pavement performance and permeability performance.