Flexural fatigue behaviour of concrete under uniaxial and biaxial stress

The main objective of this investigation was to study the effect of stress states on the flexural fatigue behaviour of concrete. The fatigue behaviours obtained from different test methods were compared, including the recently developed biaxial flexure test, ASTM C 1550 and four-point bending test. Fourteen specimens were cast and tested for each test method, under both monotonic and repeated loadings. The fatigue strength was compared with those recommended by existing design codes. Test results showed that there were no significant differences in the flexural fatigue behaviours under different stress states (i.e. uniaxial and biaxial). These results suggest that the uniaxial flexural tensile fatigue strength of concrete may be adopted for the design of concrete components subjected to biaxial flexural tensile fatigue loading.