Bond behavior of SRP/SRG systems on concrete substrate: experimental investigation

Steel reinforced polymer (SRP) and steel reinforced grout (SRG) systems have emerged as attractive technologies for the external strengthening of RC structures but several aspects still need a deeper examination for a better understanding of their response. Among them, the SRP/SRG-to-concrete shear bond behaviour is mentioned, which is crucial for the effectiveness of most applications since it represents the means of stress transfer between concrete and the composite materials. This paper contributes to filling some of these knowledge gaps by presenting the results of a wide experimental program including more than 140 shear bond tests performed on SRP/SRG systems bonded to concrete members. The main study parameters were: the concrete strength; the bonded length, the steel tape density, and quality of the surface preparation. Test results have allowed for drawing relevant information in terms of failure modes, debonding loads and effective bond lengths by varying the study parameters.