An experimental study of fatigue resistance in epoxy injection for cracked mortar and concrete considering the temperature effect

The effect of temperature on fatigue resistance in repaired mortar and concrete members through epoxy injection is experimentally studied. First, fatigue equipment capable of inducing a small movement is developed to simulate cracks, which are monitored in a real wall structure. The fatigue test is performed considering three different levels of movement amplitude and four different levels of temperature by using fatigue equipment. From the fatigue test, increases in amplitudes and temperature cause reduced resistance to fatigue.Furthermore, the effect of temperature on the failure mode of epoxy-repaired mortar is evaluated. With higher temperature, the failure mode is changed from mortar failure to mixed failure of epoxy and interface. Then, in the mixed failure mode, resistance to fatigue significantly decreases owing to the temperature effect.

Research highlights
► The movement in repaired cracks decreases because of the restraining effect.
► The failure of the mortar with epoxy injection occurs at much smaller movements.
► The failure of the mortar with epoxy injection mode depends on the temperature.
► In the mixed failure mode, resistance to fatigue decreases owing to the temperature effect.