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

Abstract

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 constitutive behavior of hybrid steel-polypropylene fiber reinforced concrete material (HFRC) subject to uniaxial 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 residual 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 constitutive model is proposed to describe the complete stress–strain relation and the damage accumulation of HFRC.