Study And Application Of Alkali-activated Slag Autoclaved Aerated Concrete Block With Municipal Solid Waste Incineration

Every year,a large amount of municipal solid waste incineration(MSWI)is generated by burning the municipal solid waste(MSW),which not only occupies the cultivated land,but also pollutes the environment.If applied it to ordinary cement-lime-sand autoclaved aerated concrete block(PT block)or alkali-activated slag autoclaved aerated concrete block(JKZ block),not only can reduce the cost of materials,but also can consume the solid waste and protect the environment.At present,the research mainly takes the MSWI as the non-active mineral admixture.In this paper,MSWI is divided into granular MSWI and powder MSWI,which can be used as fine aggregate and active mineral admixture for PT block and JKZ block.The higher value can be excavated.Based on the experiments of the small mould(100 mm × 100 mm × 100 mm)to determine the effect of the MSWI on basic properties(slurry expansion t,volume expansion rate w,pouring stability,dry density p,the compressive strength f,etc.)of PT block and JKZ block.And combined with the results of XRD,ESEM-EDS and pore structure to conduct the microcosmic mechanism analysis,which is carried out to explain macroscopical data.And the best mix proportion of small model test is selected for pilot test.The results of the study are as follows.1.With the increase of replacement ratio of the granular MSWI to river sand,the slurry expansion of PT block increases,the dry density of PT block decreases and then increases,and the volume expansion rate and the compressive strength of PT block increases first and then decreases.Granular MSWI is more active than river sand.However too larger replacement ratio of the granular MSWI to river sand deteriorates to pore structure.Therefore,the compressive strength is the highest when the replacement ratio is 20%.The JKZ block has the same rule with PT block.2.With the increase of replacement ratio of the powdery MSWI to ordinary portland cement,the slurry expansion and the volume expansion rate of PT blockdecreases,and the dry density of PT block increases.Although the activity of powder MSWI is low,it has an optimization effect on the pore structure.The compressive strength PT block and JKZ block do not decrease when substitution rate of ordinary Portland cement is not more than 10%and the substitution rate of slag is not more than 20%respectively.When the rate of substitution increased further,the low activity of powder MSWI played a leading role,so the compressive strength of PT bloek and JKZ block decreased.Other rules of JKZ block has the same rule with PT block.3.There are not zeolite and xonotlite in the hydration products of PT block with MSWI.And main hydration products of JKZ block with MSWI are calcium silicate hydrate gel,tobermorite,calcium aluminate hydrates,xonotlite and zeolite etc.,which closely cover the surface of the aggregate,and interpenetrate each other,the crystallization degree of its hydration products is better,and its structure is more compact.The average pore size is smaller,the porosity is higher,and the pore structure distribution is more reasonable.Therefore,JKZ block with MSWI has higher compressive strength compared with PT block with MSWI.4.The optimal mix proportion of PT block and JKZ block with MSWI was selected for the pilot test.The production process was basically unchanged,and the slurry expansion was controlled at 24 cm?26 cm.The compressive strength of the PT block and JKZ block with MSWI produced is 4.72 MPa and 5.66 MPa respectively,and their dry density is 630 kg/m3 and 625 kg/m3 respectively.Due to the incorporation of MSWI,the material cost of PT block and JKZ block is 23.2 yuan and 19.4 yuan respectively,which is less than that of the original PT block and JKZ block respectively.