Material comparative analysis of crack-bridging degradation of SFRC structural beams under flexural fatigue loading
Material comparative analysis of crack-bridging degradation of SFRC structural beams under flexural fatigue loading
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DOI：
10.1016/j.conbuildmat.2022.127642
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发表时间：
2022-07
影响因子：
7.4
通讯作者：
M. Adel;Koji Matsumoto;Tamon Ueda;K. Nagai
中科院分区：
文献类型：
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作者：
M. Adel;Koji Matsumoto;Tamon Ueda;K. Nagai
本研究通过实验研究了几种材料参数对钢纤维混凝土（SFRC）结构梁的影响，以及在恒定和可变的弯曲循环载荷幅度下桥接性能的退化。使用逆分析来评估裂纹桥接应力，并得出其针对最大钢筋应变的退化。制备了四个系列的 SRFC 梁并对其进行了表征，这些梁具有不同的混凝土抗压强度、两种不同体积分数的钩端钢纤维形状和两种纵向配筋率。结果表明，混凝土强度较高的梁的裂纹桥接退化率较低，疲劳寿命较长，残余承载力较高。此外，SFRC 断裂能对疲劳响应具有显着影响，断裂能越高，裂纹桥接退化率越低。然而，与单钩纤维相比，双钩钢纤维对控制 SFRC 梁的裂纹桥接退化速率和弯曲循环响应的影响相对较小。还证明，较低的纵向钢筋比会导致较高的钢筋应变率，但对裂纹桥接应力没有影响。提出了 SFRC 梁的裂纹桥接退化图，该图根据疲劳寿命期间的机械性能定量捕获多个材料参数的影响。
This study experimentally investigates the influence of several material parameters on steel fiber reinforced concrete (SFRC) structural beams and their crack-bridging degradation over constant and variable amplitudes of flexural cyclic loading. Crack-bridging stress is evaluated using inverse analysis and its degradation against maximum rebars strain is derived. Four series of SRFC beams are prepared and characterized with different concrete compressive strengths, hooked-end steel fiber shapes in two different volume fractions, and two longitudinal reinforcement ratios. The results reveal lower crack-bridging degradation rates, and associated longer fatigue life and higher residual capacity, for beams with higher concrete strength. Further, SFRC fracture energy is shown to have a significant effect on fatigue response, with higher fracture energy associated with lower rates of crack-bridging degradation. However, steel fibers with double hooks are shown to have a relatively insignificant effect on controlling crack-bridging degradation rates and the flexural cyclic responses of SFRC beams as compared to single hook fibers. Also demonstrated is that a lower longitudinal reinforcement ratio leads to higher rebar strain rates with no influence on crack-bridging stress. Crack-bridging degradation diagrams are proposed for SFRC beams that quantitatively capture several material parameters effects based on their mechanical properties over the fatigue life.