超高性能混凝土（UHPC）具有优异的抗压强度和延展性。然而，UHPC 的广泛利用受到了成本高昂、碳排放量大以及钢纤维易腐蚀等因素的阻碍。本研究探索了一种创新方法，引入聚丙烯纤维（PPF）和聚甲醛纤维（POMF）作为钢纤维（SF）的替代品来制备混合纤维增强超高性能混凝土（HUHPC），总纤维含量3% 体积 研究了不同PPF/POMF替代SF比例对HUHPC流动性、压缩性能和拉伸性能的影响及其机理。建立了考虑PPF/POMF替代比的HUHPC轴向拉伸静力本构模型，提出了考虑力学性能的综合环境效益评价指标和经济效益评价指标。结果表明，使用低模量的PPF和POMF替代高模量的SF显着改善了HUHPC的流动性。尽管由于使用低模量、低强度的PPF和POMF作为SF的替代品，HUHPC的压缩和拉伸强度有所下降，但它改变了传统UHPC的轴向拉伸应力应变行为，显着提高了其拉伸韧性。本研究建立的HUHPC轴向本构模型有效地预测了HUHPC的拉伸应力-应变行为。重要的是，综合环评指数显示，与传统UHPC相比，HUHPC具有优越的环境效益和经济效益，可大幅降低成本。通过纤维杂化开发 HUHPC 为低碳、经济高效的 UHPC 生产提供了一种有前景的策略，对 UHPC 的更广泛采用和应用具有重要意义。

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Ultra-high performance concrete (UHPC) has excellent compressive strength and ductility. Nevertheless, the extensive utilization of UHPC has been impeded by factors including the exorbitant cost, substantial carbon emissions, and vulnerability to corrosion associated with steel fibers. This study explores an innovative approach by introducing polypropylene fibers (PPF) and polyoxymethylene fibers (POMF) as replacements for steel fibers (SF) in the preparation of hybrid fiber-reinforced ultra-high-performance concrete (HUHPC), with a total fiber content of 3% vol. The influence and mechanism of different PPF/POMF replacement ratios for SF on the flowability, compressive performance, and tensile behavior of HUHPC were investigated. An axial tensile static constitutive model for HUHPC considering the PPF/POMF replacement ratio was established, and a comprehensive environmental benefit assessment index and economic benefit assessment index considering mechanical performance were proposed. The results showed that using PPF and POMF with low modulus as replacements for high-modulus SF significantly improved the flowability of HUHPC. Notwithstanding there is a decrease in compressive and tensile strength of HUHPC resulting from the utilization of low-modulus and low-strength PPF and POMF as substitutes for SF, it modified the axial tensile stress-strain behavior of conventional UHPC and notably improved its tensile toughness. The established axial constitutive model for HUHPC in this study effectively predicted the tensile stress-strain behavior of HUHPC. Importantly, the comprehensive environmental assessment index reveals that HUHPC offers superior environmental and economic benefits compared to traditional UHPC, leading to substantial cost reductions. The development of HUHPC through fiber hybridization presents a promising strategy for the low-carbon and cost-effective production of UHPC, holding significant implications for the broader adoption and application of UHPC.