High-Temperature Deterioration Mechanism of Textile-Reinforced Concrete with Different Cementitious Materials

Abstract

Textile-reinforced concrete (TRC), a new composite material commonly used for repair and reinforcement of engineered structural surfaces, is easily affected by high temperatures in the event of fire. Therefore, when investigating the fire resistance of this material, it is important to evaluate and improve its high-temperature mechanical properties. In this study, ordinary portland cement and high-alumina cement TRC were prepared, with various proportions of metakaolin used to replace the cement, to investigate the changes in the mechanical properties of TRC and its deterioration mechanism. The experimental results showed that metakaolin improved the mechanical properties of ordinary portland cement sheets at low temperatures, with optimum substitutions of 15% and 20% in ordinary portland cement and high-alumina cement, respectively. Moreover, basalt fiber woven mesh was shown to significantly improve the ductility and flexural properties of TRC sheets, and high-alumina cement-based TRC exhibited superior bending properties at 800°C with 216.4% ultimate improvement over ordinary portland cement. The results of microscopic analysis and X-ray diffraction (XRD) experiments revealed that the decrease in the high-temperature mechanical performance of the TRC sheets was caused by a combination of high-temperature damage to the matrix concrete, deterioration or oxidative deterioration of the fibers themselves, and damage to the bonding surface of both the concrete and the fibers. At high temperatures, the microstructure of the high-alumina cement TRC was tighter and bonded more effectively to the basalt fiber grid.