In this study, the splitting tests were conducted to examine the effect of strain rate on the splitting tensile performance of high-strength ultrahigh-toughness cementitious composites (HS-UHTCCs). Hydraulic machine and split Hopkinson pressure bar (SHPB) were used to investigate the tensile properties of HS-UHTCCs. The strain rates ranged from 10−6 to 10−3 s−1 for hydraulic machine experiments and from 5 to 15 s−1 for SHPB tests, respectively. The splitting tensile strength, tensile stress-strain curves, dynamic increase factor (DIF) and energy absorption ability of HS-UHTCCs were analyzed. The new DIF models proposed for HS-UHTCCs fit well with the experimental data. In addition, the failure modes of specimens and fibers were investigated. The splitting tensile strain was obtained from digital image correlation (DIC) tests. The results indicate that the strain rate has a significant effect on the splitting tensile strength and energy absorption ability of HS-UHTCCs. On the contrary, the average splitting tensile strain showed a decreasing trend with the increase of strain rate. Besides, the DIF model of HS-UHTCCs was proposed with experimental data. The failure modes of specimens changed at high strain rates, transitioning from remaining intact to completely splitting into half. Two failure patterns of polyethylene (PE) fibers included pull-out failure and rupture were observed, while steel fibers experienced pull-out failure.

中文翻译：

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高强度超高韧性水泥基复合材料 （HS-UHTCCs） 的动态劈裂拉伸性能


本研究通过劈裂试验研究了应变率对高强度超高韧性水泥基复合材料 （HS-UHTCCs） 劈裂拉伸性能的影响。采用液压机和分体式霍普金森压力杆 （SHPB） 研究了 HS-UHTCCs 的拉伸性能。液压机实验的应变率范围为 10-6 至 10-3 s-1，SHPB 测试的应变率范围为 5 至 15 s-1。分析了 HS-UHTCCs 的劈裂拉伸强度、拉伸应力-应变曲线、动态增加因子 （DIF） 和能量吸收能力。为 HS-UHTCCs 提出的新 DIF 模型与实验数据吻合较好。此外，还研究了试件和纤维的破坏模式。劈裂拉伸应变由数字图像相关 （DIC） 试验获得。结果表明，应变速率对HS-UHTCCs的劈裂拉伸强度和能量吸收能力有显著影响。相反，平均劈裂拉伸应变随应变速率的增加呈减小趋势。此外，结合实验数据提出了 HS-UHTCCs 的 DIF 模型。试样的破坏模式在高应变速率下发生变化，从保持完整过渡到完全分裂成两半。观察到聚乙烯 （PE） 纤维的 2 种失效模式，包括拉出破坏和断裂，而钢纤维则出现拉出破坏。