Research on a Composite Biomass Insulation Material with Geopolymers as Binders and Forestry Waste as Fillers

Abstract

A composite biomass insulation material, which uses geopolymers as adhesives and forestry waste as fillers, was proposed and experimentally tested. The orthogonal experimental method was adopted to analyze the optimum theoretical oxide molar ratios and the mass ratio of mixing water to binder (mw2/mB) for preparing geopolymers. The influences of curing regimes (including one-stage and two-stage curing methods) and mw2/mB ratios of the insulation materials on mechanical, thermal, and hydraulic performances were also studied by experiment. The results indicated that the optimum combination scheme of preparing geopolymers was molar ratio xSiO2 / xNa2O = 3.3, xSiO2 / xAl2O3 = 3.2 and mw2/mB = 0.5 with the highest mechanical strength of 34.21 MPa. Besides, the best curing conditions of the composite material were the curing temperatures of 85°C and 70°C under the two-stage curing regime, which could achieve the low heat conductivity of 0.123 and 0.125 W/(m⋅K), and the high mechanical strength of 1.70 MPa and 1.71 MPa, respectively. The optimum mw2/mB ratios of the biomass material were 0.5 to 0.55 with heat conductivity of 0.114 to 0.125 W/(m⋅K). This novel composite insulation material has satisfying physical performances, which is helpful for achieving building energy conservation.