The effect of repairing cracks with epoxy injection on bending stiffness of reinforced concrete beams

In this experimental study, the cracks which occur in predamaged RC beams, exposed to reversed cyclic loading, are repaired by epoxy injection and its effect on flexural stiffness is investigated. The flexural stiffness is calculated from the initial tangent of the load-displacement curves throughout the study.Results of the experiments indicate that recovery in flexural stiffness of cracked RC beams repaired by epoxy injection is mainly related with the quality of application and crack width. Satisfactory results and increase in flexural stiffness have been achieved for mid-level cracks. However, in case of minor cracks, due to poor application of epoxy injection, any increase in flexural stiffness could not be achieved. In case of large cracks where the amount of the injected epoxy is large, the observed increase in the flexural stiffness is believed to be related with the elasticity modulus of hardened epoxy.