Experimental study on the fatigue behaviour of RC beams strengthened with TRC after sustained load corrosion

Abstract

To study the fatigue properties of reinforced concrete (RC) beams strengthened with textile reinforced concrete (TRC), which consisted of a hybrid textile made from carbon and E-glass yarns and high performance concrete, after sustaining load corrosion, three RC beams without TRC and four RC beams with TRC were designed. Among these beams, one strengthened beam and one un-strengthened beam were not subjected to sustaining load corrosion, while the other five beams were immersed in a sodium chloride solution at a concentration of 5% and were subjected to different loads. After six months of dry-wet cycles, all of the beams were subjected to the bending fatigue test. The results showed that the distribution of fatigue cracks and the fatigue life of the strengthened beams were better than those of the un-strengthened beams regardless of their subjection to corrosion; however, corrosion was shown to weaken the bond between the TRC and the old concrete. The fatigue life of the beams was affected when they sustained loads because of the initial deformation that appeared. The existence of an initial deformation decreased the amplitude difference of the beams that suffered from corrosion. The development of deflection in the strengthened beams with corrosion could be divided into the following three stages: initial, stable, and rapid stages; the development of residual deflection exhibited an initially increasing and then decreasing tendency. The combination of sustained load and corrosion decreased the fatigue life of the beams more than either the sustained load or the corrosion alone.