Failure in plain and reinforced concrete - An analysis of crack width and crack spacing

The proper prediction of crack widths in plain concrete and the spacing of primary cracks in reinforced concrete are the subject of this paper. Attention Is focused on the influence of the crack concept. A comparison has been made between the standard crack model, the crack model with the fracture energy as a separate parameter, the rate-dependent crack model and the gradient crack model. It is shown that for reinforced concrete, use of one of the first two models results in a random location of primary cracks and consequently in a random value for the crack spacing. The effect of the inclusion of a length scale parameter in the latter two models has been determined with respect to the crack width in plain concrete and the crack spacing in reinforced concrete. Furthermore, attention is paid to the crucial role of the bond-slip characteristic in predicting crack spacing in reinforced elements. Copyright (C) 1996 Elsevier Science Ltd.