Preparation of building insulation foam materials by recycling industrial and agroforestry wastes

Energy shortage and environmental pollution have aroused widespread attention in the social circle. By combining industrial (waste photovoltaic glass powder (WPGP) and blast furnace slag (BFS)) and agroforestry wastes (rice husk ash (RHA) and plant ash (PA)) with alkali activator, 14 kinds of building insulation foam materials (BIFM) were prepared for the first time. The dry density, thermal conductivity, compressive strength, volumetric water absorption, pore parameters and microstructure of BIFM were tested. The effects of Na₂O content, sodium silicate modulus and RHA content on the above indexes were discussed. The relationship among dry density, thermal conductivity and porosity of BIFM was discussed. The CO₂ emissions and energy consumption of 14 kinds of BIFMs were estimated using a simplified method. The test results showed that the effects of Na₂O content and sodium silicate modulus on the properties of BIFM were complementary. When the mass fraction of RHA was 15%, sodium silicate modulus was 1.4, and Na₂O content was 8%, the optimum thermal conductivity was 0.0497 W/(m·K). Encouragingly, BIFM was beneficial in terms of both energy consumption and carbon footprint compared to traditional building insulation materials. The prepared BIFM can be used as a promising building insulation material.