Corrosion-Damaged RC Beams Repaired with Fabric-Reinforced Cementitious Matrix

Abstract

The structural performance of corrosion-damaged reinforced concrete (RC) beams repaired with fabric-reinforced cementitious matrix (FRCM) was investigated. Eleven RC beams were constructed and tested in flexure under four-point load configuration. Nine beams were subjected to an accelerated corrosion process for 70 days to obtain an average mass loss of 13% in the tensile steel reinforcing bars while two other beams were tested as controls. One corroded beam was repaired with carbon fiber-reinforced polymer (CFRP) before testing for comparison. The test parameters included the number of fabric plies (1-4), the FRCM repair scheme (end-anchored and continuous U-wrapped strips), and FRCM materials [carbon and polyparaphenylene benzobisoxazole (PBO)]. Test results showed that corrosion slightly reduced the yield and ultimate strengths of the beams. The use of FRCM increased the ultimate capacity of corroded beams between 5 and 52% and their yield strength between 6 and 22% of those of the uncorroded virgin beam. Beams repaired with U-wrapped FRCM strips showed higher capacity and higher ductility than those repaired with the end-anchored bottom strips having a similar number of layers. A high gain in the flexural capacity and a low ductility index were reported for specimens with a high amount of FRCM layers. A new factor was incorporated in the design equations of the ACI 549.4R-13 to account for the FRCM scheme.