The effects of the fiber orientation and content on the behavior of steel fiber-reinforced concrete (SFRC) under static and cyclic compressive loads are studied using the computed tomography (CT) technique, and the resistance mechanisms of the fibers are carefully observed. The results suggest that the intrinsic scatter in the fatigue life could be partially explained by the essential scatter in the fiber orientation and content. On the contrary, no relationship is observed between the intrinsic scatter in compressive strength and fiber orientation and content, which suggests that the compressive strength of the specimens is mainly due to their concrete matrix.
