Study on Preparation and Pore Structure of Autoclaved Aerated Lightweight Concrete with Iron Tailings Sand
In order to improve the macroscopic pore structure deterioration of autoclaved aerated lightweight concrete caused by the excessive admixture of iron tailings sand,the regulating effects of the content of gas-foaming agent(aluminum powder)and the mass ratio of gas-foaming agent and foam stabilizer(hydroxypropyl methyl cellulose)on the macroscopic pore structure of autoclaved aerated lightweight concrete with iron tailings sand and the effects on the compressive strength,bulk density and thermal conductivity of the specimens were studied.The results show that when the mass ratio of gas-foaming agent and foam stabilizer is 1∶5 and the content of gas-foaming agent is 0.09%,the autoclaved aerated lightweight concrete with iron tailings sand has moderate compressive strength and bulk density,which is close to the requirements of strength grade A2.5 and bulk density grade B05 specified in autoclaved aerated concrete block(GB/T 11968-2020).On this basis,further increasing the content of foam stabilizer to the mass ratio of gas-foaming agent and foam stabilizer of 1∶7 can effectively increase the proportion of tiny pores(pore area≤0.5 mm2),improve the uniformity of pores,reduce the interconnection rate of pores,so that the unit volume density of autoclaved aerated lightweight concrete with iron tailings sand can withstand pressure increase by 5.19%,and 6.8%lower thermal conductivity,with more excellent compressive and thermal insulation properties.
Iron tailings sandAutoclaved aerated lightweight concreteFoam stabilizerHydroxypropyl methyl cellulosePore structure