Experimental Study On Application Of Waste Incineration Ash In Cement Stabilized Macadam Layer

Environmental risk control and mechanical properties of the mixture are the two main aspects affecting the application of waste incineration ash in subgrade.Although MIBA is similar to natural aggregate in some performance aspects,due to the differences in waste raw material composition,incineration mode,incinerator type and air pollution control system design,the components of MIBA are also different.Therefore,there is no unified standard for the application of MIBA in roadbed.In order to explore the influence of MIBA stabilization mode on the pavement performance of the mixture,and to determine the feasibility of applying MIBA to subgrade,so that it can provide reference for the application of MIBA to subgrade engineering in Beijing.In this paper,the municipal solid waste incineration bottom ash and fly ash of a municipal solid waste incineration plant in Beijing is taken as the research object.?1?Macroscopic and microscopic multi-scale experiments were carried out to study the physicochemical and engineering characteristics of MSW incineration ash.The results show that MIBA has the characteristics of low specific gravity,high porosity,high moisture content and high crushing index compared with the related properties of ordinary aggregates,which affect the compressive strength of MSW incineration ash as aggregate to a certain extent.However,the content of oxides such as SiO₂,CaO and Al₂O₃ is higher,which provides MIBA with higher compressive strength and strong acid and alkali resistance.At the same time,the loss on ignition and the content of organic matter of MIBA meet the requirements of relevant specifications,making it possible for MIBA to be used as aggregate substitute material.ICP-MS was used to study the high content of heavy metals Zn and Pb,and environmental risk assessment was needed in the project of its resource utilization.?2?The mix ratio of cement-stabilized lime-slag macadam was studied by orthogonal test.Considering three factors of cement content,MIBA content and MIFA substitution,nine groups of mix ratio were designed,and the unconfined compressive strength of 7d,14d and 28d was taken as evaluation index.At the same time,three kinds of cement-stabilized macadam samples with different cement content were set as standard control.The compaction test shows that the maximum dry density and optimum moisture content increase with the increase of cement content,and the MIBA and MIFA content have a great influence on the optimum moisture content and maximum dry density of the mixture under similar cement content.?3?The orthogonal test results show that the optimum unconfined compressive strength schemes for 7d,14d and 28d are A_K3B_K3C_K1,A_K3B_K3C_K1 and A_K3B_K3C_K1,respectively.According to the influence degree of each factor,the comprehensive optimum scheme is A_K3B_K3C_K1,that is,the optimum mixture ratio is 5.5%cement content,25%slag content and 8.5%fly ash content,and the leaching of heavy metals does not exceed the standard.