A practical approach to determine fracture toughness of concrete by three-point bending specimens

All engineering materials contain cracks and crack-like defects, these cracks can coalesce and grow over time and can lead to collapse or to a condition that significantly reduces the service life of the structure. Considering the cost of construction of engineering structures, the service life of the structure is expected to be long. In order to ensure the longevity of the structures, the nature of the phenomena such as the formation, propagation and coalescence of these cracks has been thoroughly examined and the discipline of fracture mechanics has emerged as a result of these studies. Beam specimens are frequently used in fracture mechanics. In this context, the fracture toughness parameters of geometrically similar beam specimens with span-to-depth ratio of 2.5 in the existing studies in the literature were obtained based on the asymptotic approach of Hu and Wittmann, the effective crack lengths were calculated for each specimen and a practical formula was developed to obtain the non-linear fracture toughness parameter for one-dimensional beams with edge cracks with a span-to-depth ratio of 2.5. As a result, by means of this formula, a useful method for the practical determination of the fracture toughness parameter of single sized beam specimens tested with simple test equipment has been introduced to the scientific world through this thesis work. Keywords: Fracture Mechanics, Cracked Concrete, Fracture Toughness Parameter, Asymptotic Approach