Utilization Of Municipal Solid Waste Incinerator Bottom Ash In Concrete

Along with the accelerating process of urbanization, the expansion of the city scale and the improvement of residents’living standards, large amounts of municipal solid waste (MSW) have been generated in China. After incineration, waste is reduced by85%-90%in volume and65%-80%in mass, but Municipal solid waste incineration(MSWI) bottom ash, which is one of the major by-products, may causes secondary pollution. Reuse of the municipal solid waste incineration bottom ash can save the land for waste occupation. There are benefits to reuse bottom ash such as energy saving, emission reduction and resource recycling. The resource utilization of MSWI bottom ash will likely become a feasible and effective management strategy.The aim of the present work was to investigate the use of washed MSWI bottom ash as a partial sole replacement for cement and the optimum usage in concrete mixes.Initially, the physical and chemical properties of the raw materials; Before reusing in concrete we investigated the feasibility of using the MSWI bottom ash as a construction material, different cement mortar mixtures were prepared by blending bottom ash with ordinary Portland cement and standard sand in different proportions (10%,20%,25%and30%). The solidified specimen were tested for work performance, mechanical property and pozzolanic activity index at different curing times, the primary replacement level of bottom ash is obtained. To evaluate the effect of introducing bottom ash into concrete and the optimum usage, concrete mixtures were prepared by blending MSWI bottom ash with ordinary Portland cement and aggregate (gravel and sand) in different proportions (10%,20%and30%). By comparing the compressive strength, tensile strength,shrinkage, ant-carbonization, frost resistance and the permeability resistance experimental results of concrete with and without MSWI bottom ash, the optimum value of bottom ash is obtained.The results show that the main chemical compositions in the MSWI bottom belong to CaO-SiO2-Al2O3-Fe2O3system,which is analogy with the common pozzolanic mineral admixtures used in cement-based materials. MSWI bottom ash reduce the consistency of cement mortar, and the initial and final of setting time was slightly retarded than the control specimen, but the setting time met the requirements of construction requirement. Replacing cement by no more than25%of MSWI bottom ash reuse in cement mortar obtained better mechanical properties of the cement mortar by the filling effect of the pozzolanic product. MSWI bottom ash could be used as a replacement for cement in concrete, and with in a certain range (less than30%) MSWI bottom ash addition, the performance or strength of the concrete mixtures had not be impacted, and concrete has small shrinkage, excellent ant-carbonization, ant-permeability and frost-resistance.