As far as the environment protection problem is concerned, concrete construction industry has to alter the thinking from new innovation into rehabilitation as possible. In consequence, it is felt valid and necessary to figured out more advanced mechanical behavior of repaired concrete, especially the load capacity and fracture toughness as after being subjected to cyclic load.
This paper presents a study to investigate the behavior of the epoxy-repaired concrete subjected to cyclic load. Three-point bending test on a single-edged beams were conducted in a closed-loop material testing system (MTS) to examine the performance of concrete after being repaired. The number of cyclic load at failure of the repaired concrete subjected to various range of cyclic loads were investigated. The fracture properties including load capacity, fracture toughness and cyclic numbers were also observed. The fracture toughness, in terms of critical stress intensity factor by Jenq and Shah and fracture energy by Hillerburg, were evaluated for the concrete before and after the test. The results showed that the cyclic number to at failure for the concrete repaired with epoxy are tremendously increasing as compared with those un-cracked for a given load range in a fatigue test. However, the fracture toughness of the repaired concrete decrease after the cyclic load.

Keywords:Fatique, repaired concrete, epoxy, fracture toughness