Calculation method of bond strength between rebar and steel fibre reinforced concrete

Abstract

According to the significant deformation and crack propagation of steel fibre reinforced concrete (SFRC), the expression of hoop elongation for SFRC is established. Furthermore, the calculation method of bond strength between rebar and SFRC is proposed by the elasticity theory, fictitious crack theory and post-cracking softening model. The method is verified by the test results. The effects of relative cover thickness (ratio of concrete cover to rebar diameter), crack number and rebar diameter on the relative bond strength (ratio of bond strength to SFRC tensile strength) are analyzed. The results show that the relative bond strength of rebar embedded in SFRC is between plastic solution and partially elastic solution. Within 0.5% - 1.0% volumetric ratio of steel fibre, the relative bond strength increases with the increase of relative cover thickness and crack number, but reduces with the increase of rebar diameter. However, when the crack number is more than 5 or the rebar diameter is more than 32 mm, the variations of crack number and rebar diameter have insignificant effects on the relative bond strength