Fracture toughness of cement-based materials

Concrete is known to be a brittle material, yet there is no acceptable material parameter to quantify the fracture toughness of concrete. With an increase in efficiency and accuracy possible with numerical methods, a need to define a criterion for crack growth thus becomes evident. In this paper, various theoretical models which describe crack growth are summarized. It is shown that a single parameter such as classical stress intensity factor cannot adequately describe fracture processes in concrete. A recently proposed two-parameter fracture model is described. Some measurements of crack profile as the crack propagates observed using laser holography are also presented.