Influences of surface treatment on the mechanical performances of carbon and basalt textiles-reinforced concretes under harsh environments

The exposure to elevated temperatures and alkaline concrete pore solution can deteriorate the polymer coating in textile-reinforced concrete (TRC) and degrade its mechanical performance. To address this concern, this study experimentally investigated the influence of surface treatments on the elevated temperature resistance of carbon textile-reinforced concrete (CTRC) and basalt textile-reinforced concrete (BTRC) and durability performance in the marine environment. Three types of surface treatments, including epoxy impregnation, immersion in nano-silica suspension, and combined treatment with the silane coupling agent and nano-silica, were utilized to enhance the elevated temperature resistance and durability properties of CTRC and BTRC. The flexural strength results revealed that the modification effect of nano-silica immersion on the interfacial bonding of CTRC was greater than that of the BTRC, and the improvement can be further enhanced by using the silane coupling agent. In addition, the in-situ three-point flexural tests of CTRC and BTRC specimens were conducted under elevated temperature conditions to examine their elevated temperature resistance. It was found that exposure to elevated temperature decreases flexural performances such as first cracking strength, flexural strength, and flexural toughness of CTRC and BTRC. The elevated temperature resistance of nano-silica-treated specimens is higher than those treated with epoxy impregnation. Furthermore, the treatment with nano-silica increases the aging resistance of both CTRC and BTRC specimens in the simulated marine environment. The research outcomes can serve as a solid base for applying TRC materials in the harsh marine environment.