Fracture Mechanics of Concrete – State-of-the-Art Review

Abstract

During 1960–1970s, extensive experimental tests and numerical analyses were carried out on pre-cracked concrete specimens that systematically explained many failure characteristics of the material and structures using fracture mechanics approach. More specifically, it has been shown that the fracture mechanics can better explain the concepts of ductility, size effect, strain softening, and post-cracking behavior of concrete and structures made with concrete. The approach of fracture mechanics to study the nonlinear fracture behavior of concrete can be introduced analytically (or semi-analytically) and numerically. Under the first category, the nonlinear fracture models based on equivalent elastic crack length and using the principle of linear elastic fracture mechanics may be considered. These are simplified methods to evaluate the fracture parameters of concrete structures for application to practical engineering problems. In the second category generally, two numerical methods – discrete cracking approach and the smeared-cracking approach – are employed to simulate the nonlinear fracture process of concrete. This chapter reports briefly the development and introduction of different fracture parameters of concrete using various nonlinear fracture models. Definitions of fracture process and tensile behavior of concrete are also discussed. The methods of calculation, advantages and limitations of different nonlinear fracture models using commonly used test configurations are outlined. Introduction of weight function for calculating stress intensity factor is briefly reviewed for commonly used test specimens. Finally, scopes of this book are ascertained in view of the existing literature and recent developments on the behavior of fracture parameters of concrete.