The use of steel fiber reinforced concrete (SFRC) is becoming more and more common. Concerning bond of rebars to concrete, fibers provide passive confinement and not only improve bond performance but also affect the mode of bond failure. To analyze these aspects, a series of prismatic specimens have been subjected to the Pull Out Test, and an accurate model for predicting the mode of bond failure has been developed. The following factors have been considered: concrete compressive strength (30–50 MPa), rebar diameter (8–20 mm), concrete cover (between 30 mm and 5 times rebar diameter), fiber content (up to 70 kg/m3), and fiber slenderness and length. This model relates splitting probability to the factors considered. It has been proved that increasing fiber content restrains the risk of splitting failure. The favorable effect of fibers when preventing splitting failures has been revealed to be more important for higher concrete compressive strength values, which require higher concrete cover/diameter ratios for splitting failure to be prevented. Fiber slenderness and fiber length modify the effect of fiber content on splitting probability and therefore on minimum cover/diameter ratios required to prevent splitting failures.
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机译：钢纤维增强混凝土（SFRC）的使用变得越来越普遍。关于钢筋与混凝土的粘结，纤维提供了被动约束，不仅改善了粘结性能，而且影响了粘结破坏的方式。为了分析这些方面，已经对一系列棱柱形试样进行了拉拔测试，并且已经开发出用于预测粘结破坏模式的精确模型。考虑了以下因素：混凝土抗压强度（30–50 MPa），钢筋直径（8–20 mm），混凝土覆盖层（30 mm至钢筋直径的5倍），纤维含量（最高70 kg / m3），以及纤维细长和长度。该模型将分裂概率与所考虑的因素相关联。已经证明增加纤维含量抑制了分裂失败的风险。对于更高的混凝土抗压强度值，已证明纤维在防止劈裂故障时的有利作用更为重要，因为更高的混凝土抗压强度值需要更高的混凝土覆盖/直径比才能防止劈裂故障。纤维细长和纤维长度改变了纤维含量对分裂概率的影响，并因此改变了防止分裂失败所需的最小覆盖/直径比。
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