Strain hardening behavior can be observed in steel fiber reinforced concretes under tensile loads. In this paper, a statistical micromechanical damage framework is presented for the strain hardening steel fiber reinforced concrete (SH-SFRC) considering the interfacial slip-softening and matrix spalling effects. With a linear slip-softening interface law, an analytical model is developed for the single steel fiber pullout behavior. The crack bridging effects are reached by averaging the contribution of the fibers with different inclined angles. Afterwards, the traditional snubbing factor is modified by considering the fiber snubbing and the matrix spalling effects. By adopting the Weibull distribution, a statistical micromechanical damage model is established with the fracture mechanics based cracking criteria and the stress transfer distance. The comparison with the experimental results demonstrates that the proposed framework is capable of reproducing the SH-SFRC’s uniaxial tensile behavior well. Moreover, the impact of the interfacial slip-softening and matrix spalling effects are further discussed with the presented framework.

在钢纤维增强混凝土中，在拉伸载荷下可以观察到应变硬化行为。在本文中，考虑了界面滑移软化和基体剥落效应，提出了一种用于应变硬化钢纤维增强混凝土（SH-SFRC）的统计微机械损伤框架。利用线性滑移软化界面定律，针对单根钢纤维的拉拔行为开发了一个解析模型。通过平均具有不同倾斜角的纤维的贡献来达到裂纹桥接效果。之后，通过考虑光纤缓冲和基质剥落效应来修改传统的缓冲因子。通过采用威布尔分布，建立了基于断裂力学的破裂准则和应力传递距离的统计微机械损伤模型。与实验结果的比较表明，所提出的框架能够很好地再现SH-SFRC的单轴拉伸行为。而且，使用提出的框架进一步讨论了界面滑移软化和基质剥落效应的影响。