Impact drop weight tests, rapid chloride migration coefficient tests, single-sided freeze–thaw tests, and mechanical property tests were performed to investigate the effect of the steel fiber (SF) content on the impact resistance and durability of concrete containing nano-SiO 2 (NS). A fixed NS content of 3% and six SF contents in a range of 0–2.5% by volume were used. The impact resistance was measured based on the number of blows (N1, N2) and the impact energy. The durability of concrete includes its freeze–thaw resistance and chloride ion penetration resistance, which were appraised by the chloride ion diffusion coefficient (CDC) and relative dynamic elastic modulus (RDM), respectively. The ductility ratio was used to predict the impact resistance of concrete containing NS with different SF contents, and a linear relation between this ratio and the impact energy ( R 2 = 0.853) was found. The experimental results indicated that SF could greatly improve the impact resistance of concrete. The addition of 2.0% SF increased N1 and N2 by 106 and 169%, respectively. In addition, an appropriate SF content significantly improved the durability of the concrete, including its frost resistance (especially in the middle and late freezing–thawing cycles) and chloride ion penetration resistance. An SF content of 1.5% was the optimum, decreasing the CDC of nano-concrete by 17.1% and minimizing the RDM loss. Moreover, the 1.5% SF content increased the compressive strength of concrete containing NS by 18.5%, whereas an SF content of 2.0% increased the splitting tensile strength and flexural strength by 77 and 20%, respectively. Furthermore, when the SF content exceeded a certain value, the improvement effect on these properties began to decrease and even became negative.

中文翻译：

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钢纤维对含纳米SiO2混凝土抗冲击性能和耐久性的影响

进行冲击落锤试验、氯离子快速迁移系数试验、单面冻融试验和力学性能试验，研究钢纤维（SF）含量对含纳米SiO 2 混凝土抗冲击性和耐久性的影响（NS）。使用了 3% 的固定 NS 含量和 0-2.5% 体积范围内的六种 SF 含量。基于冲击次数(N1、N2)和冲击能量测量抗冲击性。混凝土的耐久性包括其抗冻融性和抗氯离子渗透性，分别用氯离子扩散系数（CDC）和相对动弹性模量（RDM）来评价。延性比用于预测不同SF含量的含NS混凝土的抗冲击性，并且发现该比率与冲击能量之间存在线性关系（R 2 = 0.853）。试验结果表明，SF可以大大提高混凝土的抗冲击性能。添加 2.0% SF 使 N1 和 N2 分别增加了 106% 和 169%。此外，适当的SF含量显着提高了混凝土的耐久性，包括其抗冻性（尤其是在冻融中期和后期）和氯离子渗透性。SF 含量为 1.5% 是最佳的，可将纳米混凝土的 CDC 降低 17.1%，并将 RDM 损失降至最低。此外，1.5% SF 含量使含有 NS 的混凝土的抗压强度提高了 18.5%，而 2.0% SF 含量使劈裂抗拉强度和抗弯强度分别提高了 77% 和 20%。此外，