STUDY ON BEHAVIOUR OF CORRODED RC BEAM STRENGTHENED WITH CFRP ROD, AN EXPERIMENTAL AND FINITE ELEMENT MODELLING STUDY

Abstract

The near surface mounted reinforcement technique (NSM) is one of the promising techniques used nowadays to strengthen RC structures. In the NSM technique, the Carbon Fibre Reinforced Polymer (CFRP) rods are placed inside pre-cut grooves and are bonded to the concrete with epoxy adhesive. This paper investigates the effectiveness of repair technique with Near Surface Mounted (NSM) carbon fiber-reinforced polymer (CFRP) rods to restore the mechanical performance of corrosion-damaged RC beams; it also studies the failure mode of the repaired corroded RC beam according to experimental and numerical modeling results. Experimental results and numerical modeling results of finite element FE model using ABAQUS software are obtained on two beams: one corroded beam which was exposed to a natural corrosion for 25 years and one control beam with no corrosion; both beams were 3 meters long. The two beams were repaired in flexion with one 6-mm-diameter NSM CFRP rod and then they were tested in three-points bending test up to failure. Overall stiffness and crack maps before and after repairing were studied. Ultimate capacity, ductility and failure mode are also discussed. The experimental results showed that the NSM technique increases the overall capacity (ultimate load capacity and stiffness) of control and corroded beams and allows restoring a sufficient ductility for repaired corroded elements and then restoring safety margin despite a non-classical mode of failure with the separation of concrete cover which happened in the corroded beam due to damage induced by corrosion. Finally some comparisons were made between experimental and FE numerical modeling results in order to study the specific mode of failure of corroded beam which happened by the separation of concrete cover.