Study on the recycling of ceramic polishing slag in autoclaved aerated foam concrete by response surface methodology

Abstract

In this study, the mechanical performance and thermal insulation properties of autoclaved aerated foam concrete (AAFC) with ceramic polishing slag (CPS) were investigated using chemical foaming technology at a density of 500 kg/m3. An orthogonal experimental array and the response surface methodology analysis were used to optimize the mix proportion of CPS slurry, cement, and lime content, and XRD, SEM, TG, and MIP were employed to study the microstructure and composition of the AAFC. The AAFC with the maximum compressive strength, minimum thermal conductivity, and cement consumption was obtained using the quadratic model of the response surface methodology analysis. The minimum thermal conductivity reached 0.1032 W/m·K, and a compressive strength value of 4.03 MPa was obtained for the mixtures with the CPS slurry, cement, and lime at 2804, 226.2, and 234 kg/model, respectively. The results of the microstructure development show that with an increase in CPS slurry, the compressive strength is significantly enhanced. This might be due to a sufficient hydration reaction with a proper water content. The Si and Al in the CPS react with the calcareous material and C–S–H gels to form tobermorite, thus promoting the compressive strength. In addition, the MIP indicates that the micropore (10–50 mm) content of the AAFC has a significant correlation with thermal conductivity, while macropores (>500 mm) have a significant relationship with compressive strength.