Performance of magnesium phosphate cement at elevated temperatures

Abstract

This research studied effect of elevated temperature on properties of magnesium phosphate cement (MPC). Properties, including strength, colour, mass loss, and microstructure, of MPC specimens before and after exposure different high temperature were measured or observed in this paper. Seven sample mixtures contained varying amounts of fly ash and sand are considered in the experimental program. The mechanical properties of MPC were measured by heating 40×40×160mm sample to 130, 500 and 1000°C at a rate of 10°C/min. The obtained results demonstrate that strength of MPC decreased significantly when the temperature passed 130°C. After 130°C, the amplitude of strength decreased of MPC became less with the increasing of temperature. The results of Differential thermal analysis (DTA) and thermo-gravimetric analysis (TG) indicate that the crystal water in MKP·6H2O were lost at the temperature of 125°C. The loss of crystal water in MKP·6H2O was the main reason of strength decreasing and mass loss of MPC after exposure to high temperature. The results also show that the presence of fly ash and sand decrease residual strength of MPC.