Mechanical behaviour of TRC thin-plates exposed to high temperature: experimental study

Textile reinforced concrete (TRC) is a type of composite material with great potential in lightweight and thin-walled structural components bearing high capacity. In this study, TRC thin-plates with epoxy resin impregnated fibre (type 1) and non-impregnated fibre (type 2) were exposed to high temperatures from 35°C to 800°C with the unstressed residual test method. The processed TRC thin-plates were examined through four-point bending tests with the aim of building a foundation for a fire prevention code for TRC. The results demonstrate that the ultimate load of type 1 TRC thin-plates is relatively high and does not vary significantly when the target temperature is below 200°C. The ultimate load of type 2 TRC thin-plates is lower than that of type 1, and does not vary significantly when the target temperature is below 400°C; the turning point for the reduction of ultimate load is 400–500°C, and 20% of loading capacity at normal temperature is maintained at 800°C. Stripping damage to type 1 occurs along the interface and the damage is brittle. For a target temperature of 300°C, epoxy resin is prone to deteriorate and the bursting ratio of the specimens was 100%. The damage feature of type 2 thin-plates is a slipping failure between fibre and mortar mixes, and significant ductile damage properties were observed during the damage process. The investigations were also accompanied by scanning electron microscope and alpha ray spectrometer analyses, which provided an additional basis for analysing the damaged sections of specimens. The results show that the surface flaws of the carbon filaments, matrix decomposition and the weak bond behaviour between the fibres and matrix are affected by elevated temperatures. These three factors may result in the decline of the bearing capacity of type 2 TRC thin-plates.