Long-Term Behaviour of Steel Reinforced Polymer (SRP) Systems Bonded to Concrete Substrates

Durability of externally bonded Fibre Reinforced Polymer (FRP) systems is a key concern in the field of civil engineering, due to the actions and harsh conditions these strengthening systems are exposed to during their service life. The paper will present the results of an experimental investigation of the long-term behaviour of the Steel Reinforced Polymer (SRP) system bonded to concrete when subjected to sustained loading. Long-term tests in single-lap shear configuration were performed on specimens constituted by concrete blocks reinforced with two different types of steel fabrics embedded in an epoxy resin. An innovative test setup has been designed with the aim of applying a sustained load for up to six months simultaneously to a considerable amount of specimens under fixed ageing conditions. Results in terms of retained bond strength will be also presented, showing the influence of the long-term loading on the effectiveness of the studied strengthening systems.