Effect of frp wrapping on concrete chloride ingress

Fiber Reinforced Polymer (FRP) wrapping is being successfully used to strengthen deteriorated and/or under-designed concrete structures for flexure, shear, axial, blast and impact capacities. The technique is economic, labor friendly, durable and space saving. In this study, the effect of various FRP wrapping parameters, such as type, fiber orientation, number of layers and the role of the epoxy adhesive, were investigated on the ingress of chloride ions inside the concrete substrate. A surface saline ponding approach for 16 weeks and chemical determination of chloride contents of powder concrete at various concrete depths were utilized. FRP wrapping was found to provide excellent barrier against chloride ingress (28% reduction on average). The chloride resistance came from the composite FRP laminate and not from epoxy only. The chloride content decreased rapidly and linearly with the penetration depth. Carbon FRP (CFRP) was more effective than the thinner glass FRP (GFRP), and double layers more effective than single layer. The FRP fiber directionality had no bearing on chloride penetration. Although less expensive, the less strong GFRP is at a disadvantage in providing long-term durability to concrete structures, as compared to CFRP wrapping.