Abstract：
The load-crack width curve of steel fiber reinforced concrete components is obtained from the single point loading test on the notched beam, and a flexural-tensile constitutive model is established based on this curve.The uniaxial tensile constitutive model of steel fiber reinforced concrete is proposed by modifying the conversion relationship between flexural-tensile strength and tensile strength of hooked steel fiber reinforced concrete. At the same time, finite element numerical simulation is used to obtain the failure mode, damage evolution law, and loaddeflection curve of steel fiber reinforced concrete under the action of this model. In combination with the results of the compression and bending test, the toughening and strengthening mechanism of hooked steel fiber reinforced concrete is analyzed. The study shows that when the notched steel fiber reinforced concrete beam is damaged, most of the steel fibers is pulled off and the hooks at the ends are pulled to be straight. Hooked steel fiber has a secondary strengthening effect on the flexural tensile strength of concrete components. By taking 25 kg/m3 as the benchmark,when the steel fiber content increases by 5 kg/m3, 10 kg/m3 and 15 kg/m3, the secondary peaks in the flexural-tensile strength are increased by 20.4%, 28.57% and 12.04%, respectively. In terms of failure mode and damage evolution, the hooked steel fiber reinforced concrete exhibits the characteristics of steel fiber being straightened and many cracks, small spacing and length, respectively, which shows its higher toughness. Compared with ordinary concrete,the load-deflection curve of the hooked steel fiber reinforced concrete shows a fiber reinforced section after the elastic section, intuitively demonstrating higher strength and toughness of the hooked steel fiber reinforced concrete.The numerical simulation results of the model are highly consistent with the test results, verifying the reliability of the model.
ZHOU Jiamei1 CUI Kaiqi1 FENG Tianwei1,
2 LI Ruihan1 YUE Feixiang1 XUE Zhibin1
.Study on Steel Fiber Reinforced Concrete Test and Uniaxial Tensile Constitutive Model[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(4): 163-171
2023, Vol. 60 