Fracture in quasi-brittle materials: a review of continuum damage-based approaches

Starting from the early ideas on smeared-crack modelling of quasi-brittle materials (concrete, rock) as pioneered in the late 1960s various refinements are discussed such as the shear retention factor, the tension-stiffening concept and the tension-softening concept. Next, smeared-crack models are put in the unified context of damage mechanics together with the multiple-smeared crack approach and the (closely) related microplane damage models. The concept of fracture energy is introduced for tensile and compressive loadings and is also elaborated for reinforced concrete. A concise summary is given of recent finite element concepts for cohesive-zone models (fracture energy models).