A facile low-cost method for fabricating water-based aerogel reinforced by calcium silicate waste with enhanced mechanical properties

Silica aerogel attracted much attention from scientists due to its thermal conductivity and stability. In this study, water-based aerogels were prepared through a low-cost two-step acid–base method and ambient pressure drying, using porous calcium silicate waste as the reinforcement, silica sol and deionized water as precursor and solvent, respectively. Cetyltrimethylammonium bromide (CTAB) and polyethylene glycol (PEG600) served as surfactants and pore-forming agents, respectively. The accumulation of nanosheets provided by the calcium silicate waste reduces the shrinkage of aerogel, effectively shortens the preparation time, and improves Young’s modulus. The SC-20 and SC-40 exhibit densities of 259.5 and 296.2 mg·cm⁻³, thermal conductivities of 0.0361 and 0.0423 W·m⁻¹·K⁻¹, while also possessing Young's moduli as high as 1.99 and 4.47 MPa, respectively, which are higher than 1.11 MPa for SC-0. Conclusively, the aerogels reinforced by calcium silicate waste exhibited properties like good thermal insulation, low-cost, quick preparation, environmental friendliness, and high Young’s moduli, which would show potential for use in buildings.