Central peeling failure behavior of polymer cement mortar retrofitting of reinforced concrete beams

Polymer cement mortar (PCM) retrofitting is one of the largely used strengthening inethods for repairing fatigue deteriorated highway bridge slabs in Japan. In this method, reinforcing bars are arranged underneath the lower surface of the slab and polymer cement mortar is sprayed onto them. Debonding of the PCM overlay is one of the major causes leading to failure of the repaired slabs. This paper mainly discusses this failure mechanism, its initiation, and suggests a method for quantitative analysis of the failure behavior. The stress transfer mechanism was measured using the strain distribution in the strengthening bars and a relationship for the bonding strength was obtained. Hence the relationship for the peeling load was obtained.