Bond strength of steel reinforcement embedded in ultra-high-performance fiber-reinforced concrete (UHPFRC) plays a vital role in the post-cracking behavior of reinforced UHPFRC members in flexure or tension. This paper presents an analytical study on the bond strength of steel reinforcement in UHPFRC. Three different bond-slip models, namely the modified fib model, Marchand model and the proposed model are compared in the analytical method and explicit equations are also proposed. Comparisons with test data suggest that the proposed model and explicit equations can evaluate the bond-slip behavior of reinforcement with good accuracy. Marchand model shows similar predictions of bond-slip behavior to the proposed model at different load levels, whereas the modified fib model is accurate only when the reinforcement nearly yields in tension. The embedment length required for embedded reinforcement to develop its yield and ultimate strengths can also be calculated from the analytical method and explicit equations.

中文翻译：

---

超高性能纤维混凝土中钢筋黏结滑移行为评价

嵌入在超高性能纤维混凝土 (UHPFRC) 中的钢筋的粘结强度对钢筋 UHPFRC 构件在弯曲或拉伸下的开裂后行为起着至关重要的作用。本文对 UHPFRC 中钢筋的结合强度进行了分析研究。在解析方法上比较了三种不同的键滑模型，即修正的fib模型、Marchand模型和提出的模型，并提出了显式方程。与试验数据的比较表明，所提出的模型和显式方程可以很好地评估钢筋的粘结滑移行为。Marchand 模型在不同载荷水平下显示了与所提出模型相似的粘滑行为预测，而修改后的fib只有当钢筋几乎在张力下屈服时，模型才是准确的。嵌入钢筋发展其屈服和极限强度所需的嵌入长度也可以通过分析方法和显式方程计算。