Failure mechanism of concrete, combined effects of coarse aggregates and specimen geometry

Concrete compressive strength is mostly evaluated by tests performed on cylindrical specimens with slenderness ratio two. Nevertheless, specimens with lower slenderness ratio are also used (drilled cores, cubes, etc.). Tests performed on cubes are affected by the multiaxial stress field induced by the reduced slenderness ratio. Then, the crack propagation is modified depending on the characteristics of the composite material. This paper analyzes some phenomenological aspects of the evaluation of concrete compressive strength related to the effect of coarse aggregates on the initiation and propagation of cracks. The influences of strength level and microcracking are also discussed. (C) 1997 Elsevier Science Ltd.