Endurance of insulated CFRP strengthened concrete slab subjected to fire

Abstract

Carbon Fiber reinforced polymer (CFRP) composites are recently becoming an efficacious solution in rehabilitation and strengthening work for deteriorated reinforced concrete structures, because of their superior properties. It is important to maintain a sound interaction between CFRP and concrete for transferring stresses between concrete substrate and the CFRP sheet or plate. However, the epoxy adhesive used to create the bond is very sensitive to the temperature and mechanical properties deteriorate rapidly with exposure to the elevated temperature. The CFRP sheet or plate itself cannot provide sufficient insulation to the composite system. Therefore, application of a suitable insulation onto the CFRP sheet is important especially in the application of buildings. Initially, a numerical model was developed to determine the behaviour of an insulated CFRP strengthened concrete block. The model predicted results were well agreed with the test results. Then the model was further developed to understand the behaviour of a CFRP strengthened concrete slab subjected to fire. Parametric studies were carried out to determine the fire resistance levels of the composite slab with the conductivity and the thickness of insulation.