A Study for the Fatigue Crack Growth Behavior of Concrete

콘크리트의 피로균열 성장거동에 관한 연구

In this study, the wedge splitting test (WST) specimens with various strength levels were tested to investigate the fatigue crack growth behavior of concrete. Selected test variables were concrete compressive strength with 2 levels (28 MPa, 60 MPa, 100 MPa) and maximum fatigue loading with 2 levels (75%, 85%). Fatigue testing was preceded by fracture energy test and the crack growth was measured by means of the compliance calibration method, 60 WST specimens were cast for the fatigue test, and 6 companion cylinders ($\phi$100${\times}$ 200 mm) for each batch. In fatigue test, the frequency of loading cycle was 1 Hz, and the minimum fatigue loading level was 5~10 % of ultimate monotonic loading. On the basis of the experimental results, a fracture mechanics-based empirical relationships for fatigue crack growth rate (da/dN-$\Delta$KI relationships) were presented. In addition, the effect of initial notch depth on the fracture energy and the validity of compliance calibration technique for the WST were shown.