Preparation and characterization of high-strength low-thermal-conductivity cement-based insulation materials

Thermal insulation materials with high strength and ultra-low thermal conductivity are ideal construction ones for residential infrastructure. However, high strength of materials regularly means high thermal conductivity. To solve this problem, a novel thermal insulation material was prepared by using cement as the binder, silica fume as the mineral admixture, aerogel as the coarse filler and hollow SiO 2 microsphere as the fine filler. The optimal proportion and preparation process were investigated by means of the orthogonal experiment and the single factor experiment method, respectively. On the other hand, their microstructures, in terms of aerogel particle size distribution and multi-scale composite structure were analysed by optical microscope, binarization image, scanning electron microscope. The results indicated that compared to conventional insulation materials, the produced materials in this study behaved much better performance in strength. The dry density, compressive strength and thermal conductivity reached 360 kg/m 3 , 4.55 MPa and 0.055 W/m·K, respectively. The incorporation of hollow SiO 2 microsphere and silica fume led to the much thicker pore walls of the sample, and simultaneously the prolonging of stirring time resulted in the much smaller size of aerogel, which were considered as the two primary causes of its excellent mechanical performance.