Municipal solid waste incineration bottom ash (IBA) as aerating agent for the production of aerated lightweight concrete

This study proposes an innovative approach of reutilizing municipal solid waste incineration bottom ash (IBA) for civil engineering applications. IBA is the ash residual after incineration of municipal solid waste. IBA contains a noticeable amount of metallic aluminum, which leads to expansion and cracking of concrete due to the reaction between metallic aluminum in IBA and cement when used as aggregates. Instead of pretreating IBA to remove or immobilize metallic aluminum, this paper explores the possibility of reutilizing IBA as an aerating agent to replace costly aluminum powder and as a supplementary cementitious material to partially replace cement in the production of aerated lightweight concrete. Compressive strength and dry density tests are carried out to evaluate the mechanical and physical properties of the resulting aerated lightweight concrete. The pore structure is analyzed through a microscope and with the image analysis method. The results show that IBA can be used as an aerating agent to produce aerated lightweight concrete. There is an obvious positive correlation between compressive strength and dry density of the resulting material.