FEASIBILITY STUDY ON THE UTILIZATION OF ALKALI-TREATED GROUND MUNICIPAL SOLID WASTE INCINERATION BOTTOM ASH AS CEMENT REPLACEMENT

As municipal solid waste incineration bottom ash ( IBA) contains metallic aluminum, crack and expansion issue could happen due to hydrogen gas generation when IBA is used in cement matrix. In this paper, ground IBA powder was first pre-treated with alkaline solution under certain conditions to remove metallic aluminum, and after that the treated IBA was used as cement replacement in cement mortar. The alkali treatment effects on metallic aluminum removal, chemical composition of IBA and compressive strength of cement-IBA mortar were evaluated. The results showed that metallic aluminum in IBA could be completely removed by treatment with sodium hydroxide solution, and the alkali treatment did not change the major components of IBA though some aluminum compounds changed. From the compressive strength of cement-IBA mortar, it showed that some pozzolanic property of IBA could sacrifice when IBA is treated with alkaline solution. However, the strength activity index value of cement-IBA mortar using IBA treated with sodium hydroxide solution under low temperature and low PH can still reach more than 80%, which is meaningful for practical application. In general, this paper revealed a viable way to treat IBA to be suitable for cement replacement.