Pore Structure, Hardened Performance and Sandwich Wallboard Application of Construction and Demolition Waste Residue Soil Recycled Foamed Concrete

Construction and demolition waste residue soil (CDWRS) recycled foamed concretes were prepared by introducing the original CDWRS into modified binders. Pore structure, hardened performance, and sandwich wallboard application were also investigated. The results indicated that 51 kg/m3 of water glass and 7.5 kg/m3 of gypsum could significantly increase the strength and generate a slight influence on the thermal insulation performance of CDWRS recycled foamed concrete. The largest enhancing rate of 28-day compressive strength at a density of 600 kg/m3 could reach 205.5%. Foamed concrete with 1126 kg/m3 of CDWRS, modified with water glass and gypsum, showed a low thermal conductivity of 0.11 W/(m center dot K) and a dry density of 626 kg/m3. In total, 988 kg/m3 of CDWRS in foamed concrete led to a compressive strength of 7.76 MPa, a thermal conductivity of 0.14 W/(m center dot K), and a dry density of 948 kg/m3. Utilization of the foamed concrete in the sandwich structure could fabricate energy-saving wallboards with a minimum heat transfer coefficient of 0.75 W/(m2 center dot K) and a relatively high compressive strength of 16.5 MPa, providing great confidence of CDWRS consumption in the building energy-saving field.