Low-temperature preparation of humidity self-regulating porous ceramics with high strength performance

•Humidity self-regulating ceramic (HSC) with high-performance was prepared at 600 °C.•Fumed silica and water content enhanced the flexure strength for HSC.•Nanopore size distribution affected the humidity self-regulating performance. Nanopores are very important to the moisture adsorption properties of humidity self-regulating ceramics (HSCs). As nanopores disappear easily during high temperature firing processes, it is important to prepare HSCs at low firing temperatures. But such materials generally lack the mechanical strength needed to meet building material standards. Accordingly, this study used fumed silica as a body enhancer added to volcanic mud raw material to prepare an HSC. The effects of fumed silica content, water addition and firing temperature on flexural strength, porosity, and moisture adsorption were investigated in detail. The results show that, by controlling the amounts of fumed silica and water added, the HSC can achieve high moisture adsorption of 302 g/m2. Furthermore, its flexural strength is greater than 12 MPa by only firing at 600 °C, owing to the formation of calcium silicate hydrate in the porcelain green bodies. These results indicate that this proposed method is a very promising and simple approach to the preparation of high strength performance humidity self-regulating porous ceramics.