Failure mechanism of concrete - Combined effects of coarse aggregates and strength level

Concrete is a composite, and its properties depend on the properties of the component phases and the interaction between them. It is known that the interfaces are the weakest link in concrete, playing a very important role in the process of failure. This process is strongly related with the characteristics of the aggregates (especially coarse aggregates) and with the relative differences in strength between matrix and inclusions. This paper analyzes the mechanical behavior of high strength and conventional concretes prepared with coarse aggregates having significant differences in strength, shape and surface texture, porosity and absorption, and interface bond strength. Two different gravels and two different crushed stones were used. Concrete mixtures with water/cement ratios of 0.30 and 0.50 were designed. The effects of aggregate type and strength level on concrete failure mechanism, including tensile and compressive strength, stiffness, energy of fracture, and crack pattern, are discussed. (C) 1998 Elsevier Science Ltd.