Research On Key Technology Of Municipal Solid Waste Incinerator Slag For Roadbed Filling

With the acceleration of urbanization and the rising standard of living of the people,the emissions of municipal Solid Solid Waste have been increasing rapidly.Effective treatment of municipal solid waste has always been a major problem that has plagued government agencies at all levels.The municipal solid waste incineration method has the advantages of volume reduction and resource utilization,and has become the most effective measure for urban municipal solid waste disposal.Based on this,in this paper,the physical and chemical properties,mechanics and engineering characteristics,road performance,construction technology of Taizhou municipal solid waste incinerator slag（abbreviated as rubbish slag）were studied by laboratory tests,theoretical analysis,on-site construction and quality inspection.Regardless of chemical properties,physical properties,process properties and finished product properties,the garbage slag is simply pretreated and suitable for use as a roadbed filler.Physical composition of MSWI including brick,glass,ceramics,stone,metal and organic matter,etc.The content of each component is different in different grade.The main elements of MSWI are Si,Al,Ca,Na and Mg,Fe,C,K,and heavy metals（e.g.,Cd,Hg,Pband Zn）content is very little.Leaching concentration of heavy metals in the MSWI is far lower than the hazardous waste identification standard which means less heavy metal pollution degree.In the chemical compositions of MSWI,SiO₂ has the highest content at56.7%,followed by Al₂O₃ and CaO being 13.8% and 9.7% respectively.The alkali content（K₂O+Na₂O）is 4.5%,and other chemical composition content is relatively small.The main mineral composition of MSWI isα-SiO₂,followed by calcium calcite,feldspar,etc.,mainly being the rod,needle and granular crystals.The unconfined compressive strength and elastic modules of MSWI increase as the dry density and age increase.The failure strain of saturated MSWI sample increases slightly with the development of age and the average value is 0.893%.However,the failure strain of unsaturated MSWI remains constant and the value is 0.953%.Under trixial shear test,when the confining pressure is big（σ₃>200kPa）,saturated MSWI behave plastic damage and there is no brittle failure and obvious peak.When the confining pressure is small（σ₃>200kPa）,saturated MSWI behave brittle damage and obvious peak.The internal friction angle determined by Mohr-Coulomb criterion decreases with the increasing confining pressure.Onσ₁-σ₃ coordinate,there are two straight line segments:σ₃<200 kPa andσ₃>200 kPa.The internal friction angle of saturated MSWI sample remains constant and no change with the development of age.The angle under the confining pressureσ₃<200 kPa is greater than the situation ofσ₃>200 kPa.Onτ-σcoordinate,the Mohr-Coulomb strength envelop concaves toσaxis,which is similar to the strength envelop of coarse materials.The compaction curve of MSWI has a single peak value.The maximum dry density is between 1.734g/cm³ and 1.793g/cm³.The optimum moisture content is between 11%and15%,and the CBR value is bigger than 20,which meets the performance requirements of each layer of subgrade.The construction technology of the roadbed,crushed stone roadbed and the conventional road base is basically the same,without special construction equipment and technology.