Abstract

In the present study, the shear characteristics of cementitious mortar reinforced with steel and nylon fibres were experimentally investigated through direct shear tests. The primary test parameters of the present study were fibre volume fractions of 0.15, 0.25, and 0.33% for nylon fibres; 0.5, 0.75, and 1.0% for steel fibre; and hybrid fibres comprised of different amounts of steel and nylon fibres. The test specimens were made with a singly rectangular notch at the centre to predefine the shear failure plane. Direct shear test was carried out following the guidelines specified in the Fédération Internationale de la Précontrainte (FIP) standard. The results showed that the cementitious mortar reinforced with fibres exhibited more ductility than plain mortar matrix. It was determined that the use of higher amounts of steel and nylon fibres could significantly improve the peak shear stress. Finally, a shear stress-crack slip model was constructed to idealise shear stress-crack slip curves of cementitious mortar reinforced with steel and nylon fibres, and the prediction results were consistent with the experimental results.

摘要

在本研究中，通过直接剪切试验对钢和尼龙纤维增强的水泥砂浆的剪切特性进行了实验研究。本研究的主要测试参数是尼龙纤维的纤维体积分数分别为 0.15、0.25 和 0.33%；钢纤维为 0.5、0.75 和 1.0%；以及由不同数量的钢和尼龙纤维组成的混合纤维。测试样品的中心有一个单独的矩形缺口，以预先定义剪切破坏平面。直接剪切试验是按照国际预防联合会 (FIP) 标准中规定的指导方针进行的。结果表明，纤维增强的水泥砂浆比普通砂浆基体具有更高的延展性。已经确定，使用更高量的钢和尼龙纤维可以显着提高峰值剪切应力。最后，建立剪应力-裂缝滑移模型，理想化了钢和尼龙纤维增强水泥砂浆的剪应力-裂缝滑移曲线，预测结果与试验结果一致。