Experimental investigation on recycled clay brick powder as a sand replacement in LFC

This work investigated the feasible utilisation of recycled clay brick powder in lightweight foamed concrete (LFC) as a substitute for sand. Clay brick powder was used to replace sand at ratios of 0, 50 and 100%. Different water/material ratios of 045, 0.50 and 0.55 with foam mass fractions of 2.5, 3.5 and 4.5% of the materials, respectively, were also studied and compared. A three-factor and three-horizontal orthogonal experimental design method was conducted to investigate the effect of clay brick powder on the dry density, 28 d cube compressive strength and thermal conductivity of LFC. Results show that the thermal conductivity of LFC was significantly influenced by the foam content followed by the water/material ratio. Foam content was also an important indicator for dry densities. The optimal mix proportion for each property of LFC was determined based on the experimental and orthogonal analyses. The research on this LFC proved that recycled clay brick powder could be used as a partial replacement of sand and that the proposed 50% was the proper content for clay brick powder from environmental and economic perspectives.