Dynamic properties of steel fiber-reinforced potassium magnesium phosphate cement-based materials after high-temperature treatment

Abstract

Potassium magnesium phosphate cement (MKPC) demonstrates remarkably high-temperature resistance and exhibits ceramic-like characteristics above 1000 °C. When micro steel fibers (MSF) are introduced, the resulting micro steel fiber-reinforced potassium magnesium phosphate cement-based (MSF-MKPC) material displays superior impact resistance even at high temperatures. Besides that, it is non-toxic and environmentally friendly. To investigate the impact resistance of MSF-MKPC at high temperatures, the split Hopkinson pressure bar test was conducted to analyze its dynamic mechanical properties under varying conditions, including MSF content, temperature, and strain rate. Mechanism analyses were carried out using scanning electron microscopy, mercury intrusion porosimetry, and X-ray diffraction testing. The experimental findings revealed the following key points: (1) MSF content has a more significant impact on enhancing the dynamic compressive strength of MSF-MKPC after high-temperature exposure compared to room temperature. Additionally, as the temperature increases, the residual dynamic compressive strength of MSF-MKPC initially decreases and then rises. (2) In contrast to room temperature conditions, the overall dynamic toughness index of MSF-MKPC shows an upward trend with increasing MSF content after high-temperature exposure. As the strain rate increases, the overall dynamic toughness index of MSF-MKPC also increases. (3) A dynamic impact constitutive regression equation is proposed for MSF-MKPC after high temperature, and the predicted results align well with the experimental findings. The analysis of the dynamic performance of MSF-MKPC after high temperatures can serve as a theoretical basis for the design of MSF-MKPC in future engineering applications, as well as for advancing the environmental sustainability and mechanical properties of fiber-reinforced cement-based composite materials.