UHPC tensile strength is often measured indirectly through splitting tests and flexural tests substituted for direct tensile tests. However, the tensile strain-hardening and multiple cracking performance of UHPC is highly sensitive to the testing techniques and the specimen shape used. In this paper, the double-edge wedge splitting (DEWS) test and direct tensile test were performed to evaluate the tensile strain-hardening properties and damage evolution of UHPC. The digital image correlation (DIC) technique was utilized to detect the cracking opening displacement (COD) and evaluate the damage evolution in the tensile stress vs. crack opening response. The results show that the tensile strength between DEWS and direct tensile tests in UHPC strain-hardening and strain-softening stages had a high correlation value of 0.98. Moreover, the difference in cracking strengths in the DEWS and direct tensile tests was less than 5 %, and those of peak strengths were fewer than 5.23 MPa. An improvement in relative COD increment was observed in DEWS and direct tensile tests before 90 % of the peak load at the post-peak branch. Results indicate that the DEWS testing is an efficient way to evaluate the UHPC tensile failure properties.

中文翻译：

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双刃楔劈和直接拉伸载荷下超高性能混凝土拉伸破坏行为评价


UHPC 拉伸强度通常通过劈裂试验和弯曲试验代替直接拉伸试验来间接测量。然而，UHPC 的拉伸应变硬化和多重开裂性能对测试技术和所使用的样品形状高度敏感。本文通过双刃楔劈（DEWS）试验和直接拉伸试验来评估UHPC的拉伸应变硬化性能和损伤演变。利用数字图像相关（DIC）技术来检测裂纹张开位移（COD）并评估拉应力与裂纹张开响应的损伤演变。结果表明，在UHPC应变硬化和应变软化阶段，DEWS与直接拉伸试验的拉伸强度之间具有0.98的较高相关值。此外，DEWS 和直接拉伸试验的开裂强度差异小于 5%，峰值强度小于 5.23 MPa。在峰后分支达到 90% 峰值负载之前，在 DEWS 和直接拉伸测试中观察到相对 COD 增量有所改善。结果表明，DEWS 测试是评估 UHPC 拉伸破坏性能的有效方法。