To solve the problems of corrosion and explosive spalling of traditional steel fiber ultra-high-performance concrete (UHPC) in practical applications, this study prepared UHPC by replacing steel fibers with plastic steel fibers (UHP-PRSC) and the static and dynamic mechanical behaviors had been investigated by carrying out the static tests and split Hopkinson pressure bar (SHPB) tests. The results show that under static loading, when the volume fraction of plastic steel fibers is 0.1 %–0.5 % (substitution rate 5 %–25 %), UHP-PRSC exhibits better mechanical properties than normal steel fiber UHPC. The strength of UHP-PRSC is the highest when the volume fraction of plastic fibers is 0.5 % and gradually decreases with the increasing volume content of plastic steel fibers. Under dynamic loading, the dynamic mechanical properties of UHP-PRSC are enhanced due to the reinforcing effect of plastic steel fibers at strain rates of 48.8 s−1–62.0 s−1, with a 25.4 % increase in the dynamic compressive strength of UHP-PRSC compared to normal steel fiber UHPC at a volume fraction of 0.5 % (substitution rate 25 %) of plastic steel fibers. At higher strain rates, the enhancement effect of plastic steel fibers on UHPC is weakened and even brings negative improvement. The microstructural analysis found that the replacement of steel fibers with plastic steel fibers with a volume content of 0.1 %–0.5 % (substitution rate 5 %–25 %) could produce a synergistic effect to improve the mechanical properties of UHPC and with the increase in the volume content of plastic steel fibers, the interaction between the two fibers weakened, and the mechanical properties of UHPC decreased. Based on the experimental results, an optimal replacement rate of steel fibers by plastic steel fibers was determined and the fitting parameters of the constitutive model were obtained. This study provides a reference for the feasibility of replacing steel fibers with plastic steel fibers for the preparation of UHPC.

中文翻译：

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用塑钢纤维代替钢纤维的超高性能混凝土 （UHPC） 的静态和动态机械性能


为解决传统钢纤维超高性能混凝土 （UHPC） 在实际应用中的腐蚀和爆炸剥落问题，本研究制备了塑钢纤维代钢超高性能混凝土 （UHP-PRSC） 的 UHPC，并通过进行静态试验和分体式霍普金森压力棒 （SHPB） 试验研究了其静态和动态力学行为。结果表明，在静载荷下，当塑钢纤维的体积分数为 0.1 %–0.5 %（取代率 5 %–25 %）时，UHP-PRSC 表现出优于普通钢纤维 UHPC 的力学性能。当塑料纤维的体积分数为 0.5 % 时，UHP-PRSC 的强度最高，并随着塑料钢纤维体积含量的增加而逐渐降低。在动态载荷下，由于塑钢纤维在 48.8 s-1–62.0 s-1 的应变速率下的增强作用，UHP-PRSC 的动态机械性能得到增强，与普通钢纤维 UHPC 相比，UHP-PRSC 的动态抗压强度提高了 25.4 %，体积分数为 0.5 %（替代率 25 %）塑料钢纤维。在较高的应变速率下，塑钢纤维对 UHPC 的增强作用减弱，甚至带来负向改善。微观结构分析发现，用体积含量为 0.1 %–0.5 %（取代率 5 %–25 %）的塑钢纤维替代钢纤维可以产生协同效应，提高 UHPC 的力学性能，并且随着塑钢纤维体积含量的增加，两种纤维之间的相互作用减弱， UHPC 的机械性能下降。 基于试验结果，确定了塑钢纤维对钢纤维的最优替代率，得到了本构模型的拟合参数。本研究为用塑钢纤维代替钢纤维制备 UHPC 的可行性提供了参考。