Study On Utilization Of MSWI Bottom Ash In Building Materials

MSWI ash has complex composition. Most of the MSWI ash are landfilled. Along withthe advancement of urbanization the whole city is almost surrounded by trash. This problemneeds to be solved. The ability of building materials industry to deal with solid waste is verylarge. This work focuses on MSWI bottom ash used as building materials. Discharge amountof MSWI bottom ash is considerably greater than the fly ash, and MSWI bottom ash is morelikely to be used as building materials. So our research mainly focused on grounded MSWIbottom ash.The microstructure and mineral composition were investigated by using SEM and XRD.Studies have shown that MSWI bottom ash particles have irregular shape, and its crystallineminerals consist mainly of silica and calcium carbonate. MSWI bottom ash is determined tocontain1%of metallic aluminum. This paper designed a kind of method to determine thecontent of aluminum in MSWI bottom ash. This paper compared the gas production betweenMSWI bottom ash and aluminum powder. Studies have shown that the gas production ofaverage particle size of23.2micrometer MSWI bottom ash was slightly better than70.4micrometer pure aluminum powders. In sodium hydroxide solution, gas production increasedwith the increase of pH value. In0.01mol/L sodium hydroxide solution and calciumhydroxide saturated solution, MSWI bottom ash and pure aluminum powder have similar gasproduction. Gas production increased with the increase of temperature. When MSWI bottomash has suitable fineness and suitable environment temperature, its gas production is similar tothe70.4micrometer pure aluminum.This paper made a research about MSWI bottom ash used as concrete admixture. Theresults showed that water requirement of normal consistency and initial and final setting timeincreased with the increase of the dosage of MSWI bottom ash. Mixing time has significanteffect on the mortar strength of the system. In the first12minutes, flexural strength andcompressive strength increased with the increase of stirring time, but the trend slowed downafter12minutes. MSWI bottom ash slowed down the hydration progress of the mortar system.Flexural strength and compressive strength of mortar system decreased with the increase of MSWI bottom ash.This paper made a research on the preparation of autoclaved aerated concrete (AAC)using MSWI bottom ash. The results showed that under the same dosage of23.2micrometerMSWI bottom ash and70.4micrometer pure aluminum. The former AAC has smaller andmore uniform internal bubble, and has higher dry bulk density and compressive strength. Theaddition of MSWI bottom ash does not significantly change the hydration products andmicrostructure of AAC. When the MSWI bottom ash has suitable fineness and the temperatureof the system is appropriate, MSWI bottom ash can be used to produce AAC.