The high-temperature resistance performance of TRC thin-plates with different cementitious materials: Experimental study

The paper focuses on an experimental investigation of the high-temperature resistance performance of TRC thin-plates with different cementitious materials. The effects of different cement matrix materials on the bearing capacity of the thin-plates were compared by using the unstressed residual temperature test method (URT). The results indicated that, from the macro view, TRC thin-plates with epoxy resin impregnated textile (type 1) exhibited obvious brittle failure characteristics no matter which kind of cementitious materials was selected. The bursting ratio of type 1 was 100% when the target temperature (TR) reached 400 °C; while TRC thin-plates with non-impregnated textile (type 2) were characterized by ductility. When TR ⩽ 600 °C, no significant difference in the bearing capacity was observed between the type 2 specimens using alumina cement as matrix (CAC specimens) or using ordinary Portland cement as matrix (OPC specimens). The bearing capacity of CAC specimens after 800 °C could be up to 32% of that at room temperature, which is 1.7 times of OPC specimens. Furthermore, the surface of CAC specimens did not crack or flake off which proved a better high-temperature resistance performance than OPC specimens. On the other hand from the micro perspective, thermogravimetric analysis, pore distribution and micro-structural analysis were performed to evaluate the degradation of the damaged specimens using thermogravimetric analyzer (TGA), mercury intrusion porosimeter and an environmental scanning electron microscope (SEM), respectively. The results showed that declination of bearing capacity after high temperature was mainly due to degraded filaments, the increasing pore size of matrix and the decreasing bonding between fiber and matrix. The average pore diameter of CAC matrix was only 28% of OPC matrix after 800 °C; and the loss in strength of CAC matrix was obviously less severe than that of OPC matrix between 600 °C and 800 °C. Conclusively, using high alumina cement as matrix could effectively reduce the thermal degradation of the matrix at high temperatures.