Evaluating the effect of kaliophilite on the fire resistance of geopolymer concrete

In recent years, fire accidents occur frequently and the risk of fire increases sharply, which seriously threatens the service life of concrete engineering and the safety of people's life and property. It is of great significance and is an economical and effective measure to use inorganic fire-resistant coating material. This paper shows a new approach to improve the fire resistance of alkali activated coating materials: applying alkali corrosion-resistant heat insulation filler to reduce the thermal conductivity of coating materials. Therein, kaliophilite, alkali corrosionresistant heat insulation filler, was designed and synthesized. The preparation technology of kaliophilite and its transformation mechanism was investigated, and the feasibility of enhancing the fire resistance of geopolymer was verified. The results showed that the optimum parameters, such as potassium water glass modulus (1-2), alkali concentration (8-12 mol/L) and hydrothermal temperature (140-180 degrees C), for synthesizing kaliophilite were proposed. Furthermore, the key to the purity improvement was that more content of intermediate product potassium silicaluminate hydrated (K-A-S-H) gels were generated. Moreover, synthesized kaliophilite effectively maintained the mechanical properties and improved the fire resistance of geopolymer.