Abstract Elevated temperatures can substantially affect the shear capacity of concrete. Herein we examine the effect of using different types of fibres on the behaviour of concrete at different maximum temperatures in terms of shear failure. The experiments were carried out by testing thirty specimens using two types of fibres at the age of 28 days. The study has adopted the push-off model for testing, which has been widely used as a relatively small, inexpensive, easy to perform and no need for special equipment, using either synthetic fibres or fibre cocktail. In addition, both crack width and crack slip have been investigated using LVDTs in both directions. The shear tests have been carried out at cold state after exposure to different levels of elevated temperatures. Using a bi-component synthetic fibre with 4 kg/m³ approved to enhance the concrete ductility and toughness. However, using cocktail fibres, containing both synthetic fibres of 2 kg/m³ and steel fibres of 40 kg/m³, showed higher values than using synthetic fibres in terms of shear. Finally, mixes containing fibre cocktail showed more ductile behaviour than mixes with synthetic fibres at low as well as high temperatures.

中文翻译：

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就高温后混凝土的剪切能力而言，合成纤维或纤维混合物

摘要 温度升高会显着影响混凝土的抗剪承载力。在此，我们研究了使用不同类型的纤维对不同最高温度下混凝土在剪切破坏方面的行为的影响。实验是通过使用两种类型的纤维在 28 天时测试 30 个样品来进行的。该研究采用了推开模型进行测试，该模型作为一种相对较小、价格低廉、易于执行且无需特殊设备，使用合成纤维或纤维混合物而被广泛使用。此外，已经使用 LVDT 在两个方向上研究了裂纹宽度和裂纹滑移。剪切试验是在暴露于不同程度的高温后在冷态下进行的。使用经批准的 4 kg/m³ 双组分合成纤维，以提高混凝土的延展性和韧性。然而，使用混合纤维，包含 2 kg/m³ 的合成纤维和 40 kg/m³ 的钢纤维，在剪切方面显示出比使用合成纤维更高的值。最后，在低温和高温下，含有纤维混合物的混合物比含有合成纤维的混合物表现出更多的延展性。