BEHAVIOUR OF CORRODED REINFORCED CONCRETE BEAMS STRENGTHENED WITH CFRP SHEETS UNDER FATIGUE LOADING

摘要

The fatigue behaviour of corroded reinforced concrete beams strengthened with carbon fibre reinforced polymer (CFRP) sheets are presented in this paper. The effect of using different CFRP strengthening schemes on corrosion confinement and fatigue life was investigated. Five reinforced concrete beam specimens (120 x 175 x 2000mm) were constructed. Four specimens were chloride contaminated by premixing 3% chloride ions by weight of cement in the bottom third of each specimen along the whole length. The fifth specimen did not contain any chlorides to serve as a control specimen. Two different strengthening schemes were applied; a) wrapping the specimen with CFRP sheets, and b) wrapping and flexural strengthening with CFRP sheets. The chloride-contaminated specimens were exposed to accelerated corrosion by impressing an electrical current through the main tension reinforcement. All specimens were tested in fatigue till failure. The test results showed that the use of CFRP sheets for strengthening reinforced concrete beams that are experiencing steel reinforcement corrosion is an efficient technique that can enhance the structural behaviour of these beams. The fatigue life of the CFRP strengthened-corroded specimens was increased within a range of 2.5 to 6.0 times that of a similar unstrengthened-corroded specimen.