Experimental Research on a Feasible Building Insulation Material Based Reed in China

The seemingly useless reeds are prepared as thermal insulation materials, which not only meet the requirements of environmental sustainability but also enhance the added value of reeds, creating new economic benefits. The hydrophobicity of raw biomass surfaces leads to problems such as weak bonding strength and non-dense structure in the formed materials, as well as issues related to the residual insect infestations on the surface. In this study, reed straw was used as the raw material, and foamed geopolymer was used as the binder to prepare building insulation materials based reed. To improve the interfacial adhesion performance between reed straw and foamed geopolymer, a thermochemical modification method-thermal carbonization, was proposed. In this study, the mechanical properties and hydraulic properties of the studied materials with different degrees of surface thermal modification were tested, especially the fire resistance performance, and weathering resistance performance rarely found in published literature. When the surface thermal modification condition of reed straw was 250°C (30 min), the comprehensive performance of reed-based building insulation materials was the best, when the studied material density was 321.3 kg/m³; the compressive strength was 0.59 MPa; the thermal conductivity was 0.101 W/(m·K); the pH was 11.27; the moisture absorption rate was 25.1%, and the compressive strength loss rate in wet-dry cycles was 18.5%. In addition, it had excellent fire resistance performance and weathering resistance performance. This new material can be widely used to improve the thermal insulation of traditional buildings and as sandwich filler in prefabricated buildings, such as preparing insulating walls.