A MODEL OF CALCULATING THE BOND STRENGTH BETWEEN REBARS AND CONCRETE CONSIDERING THE SOFTENING EFFECT OF CONCRETE

The bond strength between high-strength rebars and concrete with different strengths was tested by pull-out tests. The bonding mechanism between rebars and concrete was analyzed. The bilinear softening constitutive model was used to describe the softening behavior of concrete in the cracked zone, and the theoretical calculation model of the bond strength considering the influence of concrete in cracked and non-cracking zones were established. The effects of different radial displacement distributions in the cracked zone on the calculation results are studied. The validity of the calculation model was verified by comparing the calculated results with the experimental results. The results show that the computational model has the best accuracy when the radial displacement distribution in the fracture zone is assumed to be equivalently elastic. However, the bond strength of low-strength concrete specimens was overestimated under this assumption. It is suggested that the elastic assumption be used as the radial displacement distribution of concrete in the cracked zone to ensure adequate safety reserves.