Study On Purification Effect Of Rainwater Runoff On Pavement By Macroporous Open-graded Asphalt Concrete Mixed With Activated Carbon

While promoting social and economic development,road traffic has also brought about some negative effects.Among them,non-point source pollution of road surface rainwater runoff is a prominent problem that needs to be solved urgently.Studies have shown that it is feasible to use large pores to open graded asphalt concrete to remove pollutants from road surface runoff.In order to further improve the removal effect,it is envisaged to add a certain adsorption material to the macroporous open-graded asphalt mixture,and use its strong adsorption to achieve the purpose of directly removing the pollutants in the road runoff.In this paper,solid suspended solids(SS),chemical oxygen demand(COD),heavy metal lead(Pb),and zinc(Zn)are selected as the main pollutant indicators,and turbidity and pH are auxiliary indicators.On the basis of the mix ratio and composition design of the mineral material,through the independent research and development of the road rainwater runoff percolation system device and the simulated configuration of the road rainwater runoff solution,after determining the activated carbon incorporation method,the macroporous open grading of the wood-mixed powdered activated carbon on the purification effect of road surface runoff.was studied.The main work and research results of this paper are as follows:(1)The optimum ratio of the volume of the activated carbon such as activated carbon to 0%,25%,50%,75%,and 100% was determined.The road performance verification was carried out under the best oil-stone ratio.The results show that the high temperature stability,water stability and water permeability are in compliance with the corresponding technical requirements.permeability,and all meet the corresponding technical requirements of the specification.(2)The effect of mixed pollutants solution and separate pollutant solution simulated by simulated storm water runoff and seepage time on the purification effect of pavement rainwater runoff was studied.The research shows that the removal rate of the mixed solution is slightly higher than that of the single solution percolation large pore open grade asphalt concrete,but the difference is not big.The effect of self-mixing solution percolation time on the removal rate of each pollution index is not obvious in a certain time range,and all of them have small fluctuations within a certain range,but the overall variation is small.The optimum dosage of macroporous open-grade asphalt concrete activated carbon was studied.The results showed that the optimal dosage of powdered activated carbon was 100% mineral powder instead of activated carbon.(3)Under the optimum amount of activated carbon,the effects of thickness and void ratio on the effect of large pore open grade asphalt concrete on road surface rainwater runoff were studied.The results show that the removal efficiency of each pollution index increases with the increase of thickness,and the pH decreases slightly with the increase of thickness.The removal rate of SS and turbidity decreases with the increase of void ratio;the removal rate of COD and heavy metal Pb and Zn increases first and then decreases with the increase of void ratio,and the removal effect is most effective when the void ratio is about 18%.Well,the pH first decreases and then increases with the increase of the void ratio,but the variation is small.