Structural Performance of CFRP-Strengthened RC Slabs in a Corrosive Environment

This study was undertaken to address the effect of the main steel corrosion on the structural performance of RC slabs strengthened with carbon-fiber-reinforced polymer (CFRP) strips and exposed to a corrosive environment. A total of eight specimens (500×100×1,500?mm) were constructed and tested under monotonic static loading. Three specimens were CFRP-strengthened and corroded, three specimens were CFRP-strengthened and kept at room temperature, one specimen was unstrengthened and corroded, and one specimen was neither strengthened nor corroded. Three different strengthening schemes were applied: (1) externally bonded CFRP strips; (2) externally bonded CFRP strips provided with CFRP anchors; and (3) near surface mounted (NSM) CFRP strips. During the corrosion process, the specimens were placed in a small tank filled with sodium chloride (NaCl) solution concentration (3%) which covered only the slabs’ bottom third, and corrosion was induced by means of an impressed current. The corrosion process lasted for 20 days, and the average mass loss of the main steel reinforcement due to corrosion was 9%. Following corrosion, the specimens were tested under four-point bending. The experimental results showed that the increase in flexural capacity achieved using the three strengthening schemes were significantly reduced due to corrosion of the main steel. The recorded reductions in flexural strength gains for the CFRP-strengthened corroded slabs relative to the gains for the strengthened uncorroded slabs were about 55, 38, and 41% for the externally bonded CFRP system without anchors, externally bonded CFRP with anchors, and NSM-CFRP system, respectively.