Study On Road Performance Of Municipal Solid Waste Incineration Fly Ash Washing Pretreated In Asphalt Mixture

By the end of 2016,the output of Municipal solid waste is about 1.89 million tons.With the increasing of it,incineration has gradually become a preferred way because it can effectively reduce volume of waste,and recycle waste heat for power generation and heating.The fly ash produced by the incineration of Municipal solid waste contains a large number of heavy metals such as Pb,Zn,Cu,Cr and so on,which belongs to hazardous waste.Because fly ash and mineral powder have similar physical and chemical properties and the fixed effect of bitumen,therefore,it is of great significance to study the influence of fly ash on road performance of asphalt mixture.First,the fly ash is pre treated with water washing(for short,washing fly ash),The basic physical and chemical properties of washing fly ash and mineral powder are tested by XRF and BET instruments.And the technical characteristics of water washing ash as filler are analyzed.A large number of tests of water washing ash/mineral powder bitumen mortar are test through Brookfiled and DSR and BBR instruments,and the influence mechanism of water washing ash on the rheological properties of asphalt mortar is analyzed.The maximum mass percentage of water washing ash instead of mineral powder is determined.Secondly,the effect of water washing ash on anti rutting ability,low temperature cracking resistance and water stability of asphalt mixture is analyzed through a large number of washing fly ash in asphalt mixture road performance test.Abaqus software is used to simulate the mechanical properties of asphalt concrete pavement such as pavement deflection,maximum tensile strain at the bottom of floor under different washing fly ash content,and the threshold value of washing fly ash instead of mineral powder is 2.5%.Thirdly,through the sulfuric acid nitric acid method and the water tank leaching test,the leaching toxicity and release rule of heavy metals Pb,Zn,Cu,Cr,Ni and Ba in asphalt concrete under different washing fly ash content are analyzed.And the prediction model of heavy metal leaching pollution based on heavy metal content and leaching time is constructed.Then the potential ecological risk index method and guidelines for risk assessment are used to assess the environmental risk of soil and groundwater around the road of washing fly ash asphalt concrete.Finally,this paper analyzes the social and economic benefits of washing fly ashinstead of mineral powder used in asphalt pavement from the environment,energy saving,emission reduction and engineering cost.The application of the results can realize the clean and resourceful utilization of asphalt pavement to washing fly ash and improve the pavement performance of asphalt pavement,which embodies the design concept of building an economical and environment-friendly road.