This paper presents a systematic study on the feasibility of using recycled tyre polymer (RTP) fibres for mitigating the damage of concrete induced by elevated temperatures. A series of tests were conducted to investigate the effect of RTP fibres on mechanical and thermal behaviour, pore pressure build-up and microstructural evolution of concrete exposed to elevated temperatures (20, 105, 250, 400 and 600 °C), based on which the mechanism of RTP fibres in mitigating damage of concrete was explored. Results indicate that the addition of RTP fibres effectively prevented pore pressure accumulation and significantly mitigated damage of concrete at high temperatures as the melting of RTP fibres and thermal incompatibility between RTP fibres and concrete promoted the formation of interconnected pore-microcrack network of concrete. RTP fibre was proved as a promising sustainable alternative to manufactured polymer fibres for enhancing high temperature and fire resistance of concrete. The optimal RTP fibre content was 1.2 kg/m³ considering the damage mitigation efficiency and strength loss.

本文对使用再生轮胎聚合物 (RTP) 纤维减轻混凝土因高温引起的损坏的可行性进行了系统研究。进行了一系列测试来研究 RTP 纤维对暴露在高温（20、105、250、400 和 600 °C）下的混凝土的机械和热行为、孔隙压力增加和微观结构演变的影响，基于这些探讨了RTP纤维减轻混凝土损伤的机制。结果表明，由于RTP纤维的熔化以及RTP纤维与混凝土之间的热不相容性促进了混凝土孔隙-微裂纹互连网络的形成，RTP纤维的加入有效地防止了孔隙压力积累并显着减轻了混凝土在高温下的损伤。RTP 纤维被证明是一种有前途的可持续替代人造聚合物纤维，可提高混凝土的耐高温性和耐火性。最佳 RTP 纤维含量为 1.2 kg/m³考虑减损效率和强度损失。