Ultra-high performance concrete (UHPC) is vulnerable to high temperature-induced damage due to its dense microstructure. To mitigate thermal damage of UHPC, this study develops synergistic flame-retardant polymer (SFRP) fibres by introducing organic-metallic fillers and experimentally investigates the thermal properties, compressive behaviour, and microstructural evolution of SFRP fibre reinforced UHPC subjected to elevated temperatures up to 800 °C. Results indicated that the addition of SFRP fibres can effectively prevent the explosive spalling and significantly reduce the strength loss of UHPC at high temperatures due to the thermal mismatch between fibres and concrete. SFRP fibres were also proved to help greatly enhance the fire resistance and mitigate the thermal damage of UHPC, which can be attributed to the increased connectivity of pore structure, filling effect of flame-retardant polymers, and delayed degradation of micromechanical properties. The SFRP fibre content of 2.0 vol% is recommended considering the residual strength and damage mitigation efficiency.

超高性能混凝土 (UHPC) 由于其致密的微观结构，容易受到高温引起的损坏。为了减轻 UHPC 的热损伤，本研究通过引入有机金属填料开发了协同阻燃聚合物 (SFRP) 纤维，并通过实验研究了 SFRP 纤维增强 UHPC 在高达 800 ℃的高温下的热性能、压缩行为和微观结构演变。摄氏度。结果表明，SFRP纤维的加入可以有效防止爆炸剥落，并显着降低UHPC在高温下由于纤维与混凝土的热失配而导致的强度损失。SFRP 纤维也被证明有助于大大提高耐火性并减轻 UHPC 的热损伤，这可归因于孔隙结构的连通性增加、阻燃聚合物的填充效应以及微机械性能的延迟退化。考虑到剩余强度和损伤缓解效率，建议使用 2.0 vol% 的 SFRP 纤维含量。