The Performance Of Modified Pervious Asphalt Concrete With Recycled Coarse Aggregate

In order to adapt to the two trends of construction waste resource utilization and sponge city construction,this paper attempts to apply recycled coarse aggregate to pervious asphalt mixture(PAM).The methods of strengthening recycled coarse aggregate and adding fiber into the mixture are used to modify PAM,and the performance of modified pervious asphalt concrete with recycled coarse aggregate is studied.(1)The natural coarse aggregate in PAM was replaced by the untreated recycled coarse aggregate(RCA)with 0,30%,70%,100%replacement rates respectively.The effect of recycled coarse aggregate content on the best oil stone ratio and permeability coefficient of PAM was studied.The results show that the more recycled coarse aggregate is added,the greater is the best oil stone ratio of PAM;the permeability coefficient increases first and then decreases with the increase of recycled coarse aggregate,and reaches the lowest when RCA content is 70%.However,the permeability coefficient of PAM can meet the requirements of the specifications.(2)The recycled coarse aggregate was modified by three methods:cement mortar wrapped recycled aggregate(CSRCA),saturated calcium hydroxide solution soaked recycled coarse aggregate(CHRCA)and silicone resin wrapped recycled coarse aggregate(SRRCA).The natural coarse aggregate was replaced by 0,30%,70%,100%replacement ratio,The effect of the modified recycled coarse aggregate and its content on the optimum oil stone ratio and water stability of PAM was studied.The results show that after three kinds of aggregate modification,compared with the recycled coarse aggregate without any treatment,the best oil stone ratio of PAM with the same amount of recycled coarse aggregate is reduced,and the water stability is improved.After silicone resin treatment,the best oil stone ratio decreased the most,and the effect of water stability improvement was the best,followed by cement slurry treatment,and the effect of calcium hydroxide wrapping was the least obvious.(3)Basalt fiber(PF)and polyester fiber(BF)are added into the asphalt mixture,and the amount of fiber is 0.4%(based on the mass percentage of the mixture).Considering the mass ratio of 1:0,3:1,2:2,1:3,0:1 of poly basalt fiber(BF)and polyester fiber(PF),the content of recycled coarse aggregate is 100%.The effect of fiber on the optimum oil stone ratio and water stability of PAM is studied.The results show that the best oil stone ratio of PAM is increased and the water stability is improved by adding fiber.The higher the content of polyester fiber,the greater the increase of the best oil stone ratio and the higher the water stability.