Feasibility study on utilization of municipal solid waste incineration bottom ash as aerating agent for the production of autoclaved aerated concrete

Instead of pre-treating IBA to remove or to immobilize metallic aluminum, this paper proposes to utilize IBA as aerating agent to replace costly aluminum powder and as silica source to partially replace silica flour/fly ash in the production of autoclaved aerated concrete (AAC). IBA-AACs with density ranging from 600 to 800 kg/m³ were successfully synthesized by using IBA as aerating agent. For a given density, the compressive strength of IBA-AAC is higher than that of AAC due to the formation of more uniform pore structure with smaller pore size in IBA-AAC. The free drying shrinkage of IBA-AAC decreases with increasing IBA content. This may be attributed to the porosity of IBA-AAC increases while the strength and stiffness of IBA-AAC decreases with increasing IBA content. As a result, the moisture loss due to drying is faster and the resistance to volume change is reduced in IBA-AAC with higher IBA content.