Abstract
This paper presents an experimental investigation on the stress‐strain behavior and damage evolution of steel‐polypropylene hybrid fiber reinforced concrete (HFRC) with different fiber types, volume fractions, and aspect ratios. The damage evolution laws of HFRC were obtained using uniaxial cyclic compression and tension tests. The results show that the addition of hybrid fiber has a significant synergetic effect on the mechanical behavior of concrete. The peak strength, peak strain, toughness, and postpeak ductility of HFRC under both tension and compression are improved, and the damage accumulation and stiffness degradation are alleviated by increasing volume fractions of SF and PF, as well as aspect ratios of SF. Moreover, the steel fiber volume fraction shows a more pronounced effect than that of other considered factors on the enhancement of cyclic mechanical parameters of HFRC. Based on the unloading stiffness degradation process, analytical equations were, respectively, proposed to generalize the damage progression of HFRC under compression and tension, with the effects of hybrid fiber taken into consideration. Finally, the proposed uniaxial damage evolution equations combined with the calibrated concrete damaged plasticity (CDP) model in ABAQUS were used to predict the responses of HFRC materials and structural members subjected to shear and seismic loads. The comparisons between the numerical predictions and experimental results show a good agreement.
Highlights
Over the last decades, fiber reinforced concrete (FRC) has achieved rapid development and application in the field of civil engineering, which shows higher cracking resistance, toughness, tensile strength, postcracking ductility, fatigue, and seismic performance than the traditional one
In order to analyze the effects of hybrid fiber on the mechanical behavior, the corresponding envelope curves referenced as the upper boundary of the cyclic responses of the specimens are illustrated in Figure 5. e following results are found: (a) Performance Degradation
The following main conclusions can be drawn: (1) e addition of hybrid fiber improves the cyclic mechanical properties in terms of peak strength, peak strain, toughness, and postpeak ductility of hybrid fiber reinforced concrete (HFRC) under uniaxial tension and compression, which increase with increasing fiber parameters
Summary
Fiber reinforced concrete (FRC) has achieved rapid development and application in the field of civil engineering, which shows higher cracking resistance, toughness, tensile strength, postcracking ductility, fatigue, and seismic performance than the traditional one. Xu et al [14,15,16,17,18,19,20,21] systematically investigated the mechanical behaviors of HFRC under uniaxial monotonic/cyclic compression and tension as well as the true triaxial compression, and based on the corresponding test results, constitutive equations were proposed to predict the mechanical responses of HFRC materials They reported the experimental results of behaviors of HFRC structural members, i.e., short beams, deep beams, columns, beamcolumn joints etc., subjected to shear, flexure, and seismic loads. It should be mentioned that the failure of HFRC is mainly determined by the damage
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