Constitutive behavior of hybrid fiber reinforced concrete subject to uniaxial cyclic tension: Experimental study and analytical modeling

A reasonable cyclic tensile model is indispensable in the design and nonlinear analysis of fiber reinforced concrete structural members against repeated loads. This paper presents a systematic study on the con-stitutive behavior of hybrid steel-polypropylene fiber reinforced concrete material (HFRC) subject to uni-axial cyclic tension. A total of seven groups of cylindrical HFRC specimens were tested with influential factors in terms of fiber type, volume fraction and aspect ratio considered. The results show that HFRC specimens failed in a ductile manner due to the contributions of hybrid fiber on the cracking resistance at multiple length scales. It is noted that increasing the steel fiber (SF) content has a significant effect on the enhancement of the concrete cyclic tensile properties. Further improvements in the post-peak resid-ual strength and toughness can be seen for the cases with a larger SF aspect ratio that also helps alleviate the stiffness degradation of the HFRC. Furthermore, an appropriate volume content of polypropylene fiber addition can improve the deformation and energy dissipation of the matrix. Finally, a semi-empirical con-stitutive model is proposed to describe the complete stress-strain relation and the damage accumulation of HFRC. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Increasing steel fiber content significantly enhances the cyclic tensile properties of concrete, especially with a larger SF aspect ratio. Proper addition of polypropylene fiber can improve the deformation and energy dissipation of the matrix in HFRC specimens. A semi-empirical constitutive model is proposed to describe the stress-strain relation and damage accumulation of HFRC.