Fracture Properties of Concrete Based on the K R Curve Associated with Cohesive Stress Distribution

Abstract

While the double-K and double-G fracture models can predict the important stages of fracture processes like crack initiation, stable crack propagation, and unstable fracture, the complete fracture process can be analyzed with the use of the K R curve associated with cohesive stress distribution in the fracture process zone. The existing analytical method for determining the fracture parameters using the K R-curve method associated with cohesive stress distribution in the fracture process zone needs specialized numerical technique because of singularity problem at the integral boundary. In this chapter, the weight function method is extended to determine the fracture parameters associated with the K R-curve method. The use of universal form of weight function for determining the K R curve associated with cohesive stress in the fracture process zone can provide closed-form equations leading to computational efficiency and avoiding the need of the specialized numerical technique. Further, study of the influence of various factors including softening function of concrete, specimen size, specimen geometry, and loading condition on the various fracture parameters associated with the K R curve is carried out.