Effect of damaged concrete cover on the structural performance of CFRP strengthened corroded concrete beams

Corrosion of reinforcement is a serious problem and is the main cause of concrete structures deterioration costing millions of dollars even though the majority of such structures are at the early age of their expected service life. This paper presents the experimental results of damaged/repaired reinforced concrete beams. The experimental program consisted of reinforced concrete rectangular beam specimens exposed to accelerated corrosion. The corrosion rate was varied from 5% to 7.5% which represents loss in cross sectional area of the steel reinforcement in the tension side. Half of the damaged beams were repaired by bonding Carbon Fiber Reinforced Polymer (CFRP) sheets to the tension side to restore the strength loss due to corrosion. The other half of the beams were first cleaned from the contaminated concrete cover and a thorough cleaning of the rusted bars was done. A new layer of concrete was cast to replace the removed contaminated concrete. Then the CFRP sheets were attached to the new concrete layer. Corroded beams showed lower stiffness and strength than control (uncorroded) beams. Strength of damaged beams due to corrosion was restored to the undamaged state when strengthened with CFRP sheets for all strengthened beams. However, the beams with replaced concrete layer exhibited better performance in the load carrying capacity whenever bond was not the mode of failure.