粉末固废应用于透水沥青路面的浸出污染

To investigate whether some components of porous pavement material will leach or cause potential pollution during rainwater infiltration, three commonly fine solid waste materials of fly ash, diatomite and red mud were applied to porous asphalt(PA)mixture. Through the static alkali dissolution test and the laboratory simulated rainfall and infiltration test, the pH and the pollutant concentration of the leachate of PA with different fillers were tested respectively, and the effect of leachate of porous asphalt mixture on zebrafish was tested through aquatic toxicity test. Based on the macroscopic and microscopic pore characteristics test, the potential relationship among filler types, leaching pollution and material pore characteristics were revealed. The results show that the pH of the leachate of PA is between 8.2 to 8.3, and most of the alkalinity comes from fillers and aggregates, and the degree of alkali leaching is slightly stronger when diatomite and red mud are used as alternative fillers. When coal fly ash(CFA)and red mud are applied into PA, under short-term heavy rainfall events, a negligible amount of aluminum(Al)and iron(Fe)in CFA and red mud will be precipitated with runoff from PA, while the content of TN and TP in leachate is large, so it should be cautious when recycling in-situ water resources. The survival rate of zebrafish embryos in the leachate of porous asphalt material was 92%, presenting little effect on aquatic organisms. Filler types present little impact on the macroscopic pore characteristics including the total porosity, connected air void and permeability coefficient, but the porous filler significantly improves the microscopic pores of PA. In general, considering the water collection and dilution effects of the natural environment, when solid waste materials are applied as fillers in porous asphalt pavement, the risk of self-leaching pollution is relatively small.