FAILURE-MECHANISM OF CONCRETE - COMBINED EFFECTS OF COARSE AGGREGATESAND STRENGTH LEVEL

Concrete is a composite, and its properties depend on the properties o f the component phases and the interaction between them. It is known t hat the interfaces are the weakest link in concrete, playing a very im portant role in the process of failure. This process is strongly relat ed with the characteristics of the aggregates (especially coarse aggre gates) and with the relative differences in strength between matrix an d inclusions. This paper analyzes the mechanical behavior of high stre ngth and conventional concretes prepared with coarse aggregates having significant differences in strength, shape and surface texture, poros ity and absorption, and interface bond strength. Two different gravels and two different crushed stones were used. Concrete mixtures with wa ter/cement ratios of 0.30 and 0.50 were designed. The effects of aggre gate type and strength level on concrete failure mechanism, including tensile and compressive strength, stiffness, energy of fracture, and c rack pattern, are discussed. (C) 1998 Elsevier Science Ltd.