This study investigated the axial compressive behaviours of cement mortar reinforced with crimped shaped memory alloy (SMA) fibres produced by cold drawing. The performance of the crimped fibre was investigated in term of tensile behaviour, deformation recovery, recovery stress and pullout behaviour. After that, compressive tests of mortar reinforced with two types of SMA fibres, namely, dog-bone-shaped fibres and crimped fibres, were conducted to compare their compressive behaviours. The results showed that both types of SMA fibres increased the compressive strength of mortar, and a 1.0% volumetric ratio of SMA fibres is effective to increase the compressive strength of mortar, whereas a 0.5% volumetric ratio did not significantly increase the compressive strength. The recovery stress of the SMA fibres induced by the shape memory effect does not significantly increase the compressive strength of mortar. However, when crimped SMA fibres with a 1.0% volumetric ratio were heated and recovery stress was induced, they controlled volume expansion more effectively after cracking than crimped SMA fibres without recovery stress. The findings indicate that crimped SMA fibre with recovery stress can provide crack-bridging capacity.

中文翻译：

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卷曲 NiTi 形状记忆合金纤维增强砂浆圆柱体的单轴压缩行为

本研究调查了冷拔生产的卷曲形状记忆合金 (SMA) 纤维增强水泥砂浆的轴向压缩行为。在拉伸行为、变形恢复、恢复应力和拉拔行为方面研究了卷曲纤维的性能。之后，对用两种类型的 SMA 纤维（即狗骨形纤维和卷曲纤维）增强的砂浆进行了抗压试验，以比较它们的抗压性能。结果表明，两种SMA纤维均提高了砂浆的抗压强度，体积比为1.0%的SMA纤维对提高砂浆抗压强度有效，而体积比为0.5%的SMA纤维抗压强度没有明显提高。形状记忆效应引起的SMA纤维恢复应力并没有显着提高砂浆的抗压强度。然而，当加热体积比为 1.0% 的卷曲 SMA 纤维并诱导恢复应力时，它们比没有恢复应力的卷曲 SMA 纤维更有效地控制开裂后的体积膨胀。研究结果表明，具有恢复应力的卷曲 SMA 纤维可以提供裂纹桥接能力。