Influence of Specimen Size/Geometry on Shrinkage Cracking of Rings

This paper presents experimental evidence to show that a size/geometry dependence is observed in the shrinkage cracking behavior of restrained concrete structures. A theoretical model is developed to explain this behavior. First, a solution is presented to compute the stress and displacement fields of an aging, linear, viscoelastic cylinder by assuming that a uniformly distributed shrinkage strain is perfectly restrained in the radial direction at the internal surface of the cylinder. Second, a fracture mechanics failure criterion is implemented to develop time and geometry-dependent tensile stress resistance (strength) curves. Third, this model is used to illustrate the role of specimen size/geometry and material composition on the failure response. Finally, experimentally measured ages of cracking are compared with the theoretical modeling predictions.