Wang Zhanqiao, Gou Jin, Gao Danying
School of Water Conservancy Engineering, Zhengzhou University, Zhengzhou 450001, China.
School of Civil Engineering, Zhengzhou University, Zhengzhou 450002, China.
Materials (Basel). 2020 Dec 30;14(1):129. doi: 10.3390/ma14010129.
This study aimed to determine the influence of the volume fraction of steel fibers on the fracture parameters of concrete. Fifty notched steel-fiber-reinforced concrete (SFRC) beams and ordinary concrete beams with 100 mm × 100 mm × 515 mm were cast and tested via a three-point bending test. Among them, the type of steel fiber was the milling type (MF), and the volume fraction of steel fiber added was 0%, 0.5%, 1%, 1.5% and 2%, respectively. The effects of the steel fiber volume fraction (V) on the critical stress intensity factor (K), fracture energy (G), the deflection at failure(δ), the critical crack mouth opening displacement (CMOD) and the critical crack tip opening displacement (CTOD) were studied. Through the analysis of test phenomena and test data such as the load-deflection (P-δ) curve, load-crack mouth opening displacement (P-CMOD) curve and load-crack tip opening displacement (P-CTOD) curve, the following conclusions are drawn: with the increase of the steel fiber volume fraction, some fracture parameters increase gradually and maintain a certain linear growth. The gain ratio of the fracture parameters increases significantly, and the gain effect is obvious. Through this law of growth, the experimental statistical formulas of fracture energy and the critical stress intensity factor are summarized.
本研究旨在确定钢纤维体积分数对混凝土断裂参数的影响。浇筑了50根尺寸为100mm×100mm×515mm的带缺口钢纤维增强混凝土（SFRC）梁和普通混凝土梁，并通过三点弯曲试验进行测试。其中，钢纤维类型为铣削型（MF），添加的钢纤维体积分数分别为0%、0.5%、1%、1.5%和2%。研究了钢纤维体积分数（V）对临界应力强度因子（K）、断裂能（G）、破坏时的挠度（δ）、临界裂缝口张开位移（CMOD）和临界裂缝尖端张开位移（CTOD）的影响。通过对试验现象以及荷载-挠度（P-δ）曲线、荷载-裂缝口张开位移（P-CMOD）曲线和荷载-裂缝尖端张开位移（P-CTOD）曲线等试验数据的分析，得出以下结论：随着钢纤维体积分数的增加，一些断裂参数逐渐增大并保持一定的线性增长。断裂参数的增益比显著增大，增益效果明显。通过这种增长规律，总结出了断裂能和临界应力强度因子的试验统计公式。
