Performance of corroded reinforced-concrete beams in flexure strengthened using different basalt fiber textile-reinforced mortar schemes

The need for an effective method for the restoration of corrosion-damaged reinforced-concrete elements cannot be overemphasized. In this investigation, the use of textile-reinforced mortar (TRM) for external strengthening of corroded reinforced-concrete beams in flexure is examined. The degrees of corrosion considered were 10% and 20% mass losses of the tension steel at midspan. Sixteen beams were tested in four-point bending; eight beams were cast using normal grade 35 concrete and eight beams were cast with a special high-strength concrete with steel fibers. Three strengthening schemes of a single-ply basalt TRM, covering an equal area on individual beam surfaces, were employed. As expected, the corrosion had a detrimental effect on load-carrying capacity, ductility, energy absorption, and flexural stiffness of RC beams. The strengthening schemes increased the load capacity of the 10% corroded beams within a range of 7.5%-26%, thereby yielding a restoration ranging from 105% to 112% of the peak load capacity. Full recovery of load capacities was not achieved for the 20% corroded beams. The ultimate failure mode observed in all strengthened specimens was fiber rupture, indicating full utilization of composite action of basalt TRM. A U-wrap scheme gave the best load-displacement response and energy absorption recovery.