Effects Of Municipal Solid Waste Combustion Residues On The Characterization Of Cement Stabilized Macadam

With the development of economic,the production of municipal solid waste increased quickly.Even if advanced incineration treatment technology was adopted,there were still a large number of combustion residues.It included municipal solid waste incineration(MSWI)bottom ash and municipal solid wastei ncineration(MSWI)fly ash.If MSWI bottom ash and fly ash were randomly stacked or landfilled,they not only occupied land resources,but also had adverse effects on the natural environment.As a semi-rigid base material,cement stabilized macadam had been widely used because of its excellent performance.Therefore,MSWI bottom ash and fly ash were applied to cement-stabilized macadam of pavement base.In this paper,the physical and chemical properties of MSWI bottom ash and fly ash were studied.Based on this,part of aggregate and cement were replaced by MSWI bottom ash and fly ash respectively so that two semi-rigid base materials were carried out.It was also analyzed about the road performances and the environment influence of the new materials.The results concluded that.addition of MSWI fly ash had positive influence on the characterization of cement stabilized macadam.The mechanical properties of cement stabilized macadam containing MSWI fly ash was enhanced by increasing curing time.However,the strength of.cement stabilized macadam was decreased with the increase.of MSWI fly ash.content.The compressive resilience modulus,splitting strength and 7d compressive strength.of cement stabilized macadam containing 25% MSWI fly ash met the specifications of the cement stabilized macadam base course as set by the Chinese Standard.The dry shrinkage property of cement stabilized macadam can be ameliorated by MSWI fly ash.The residual compressive.strength ratio of cement stabilized macadam after freeze-thaw cycles declined.with increasing MSWI fly ash content.The concentration of investigated elements in leachates was obviously lower than the limitation of the Chinese Standard.About 25% MSWI fly ash content(<50%)was the suggested maximum dosage of CSM containing MSWI fly ash.The Substitution of MSWI bottom ash for natural aggregate reduced the unconfined compressive strength,splitting strength and compressive resilience modulus of cement stabilized macadam,but these indices met the requirements of specifications.With the addition of MSWI bottom ash,the cumulative dry shrinkage and average dry shrinkage coefficient of cement stabilized macadam containing MSWI bottom ash were lower than cement stabilized macadam without MSWI bottom ash.The dry shrinkage property of cement stabilized macadam can be ameliorated by MSWI bottom ash.Cement stabilized macadam with 10% MSWI bottom ash had good freeze-thaw resistance.All cement stabilized macadam containing MSWI bottom ash met the semi-rigid materials freezing resistance requirements in medium and heavy frozen regions.Therefore,the all test results showed that the proportion of natural aggregate in cement stabilized macadam replaced by MSWI bottom ash should be 5%~20%.Meanwhile,the mechanical properties and road performance of cement stabilized macadam would be better.