Advances in Knowledge of the Fracture Properties of Cohesive Materials: Fired-Clay and Tuff Bricks

This paper presents an experimental work aimed at determining the fracture properties of fired-clay and tuff brick, obtained from construction sites of existing buildings and a commercially available fired-clay brick. This paper provides a range of values of the fracture properties of natural and artificial bricks used in existing constructions. Natural and artificial stones are quasi-brittle materials and the cohesive crack model can be used to describe the propagation of cracks in these materials. However, some of the parameters of the cohesive crack model are calibrated against a large set of data of concrete specimens and might not be suitable for other quasi-brittle materials that feature a smaller fracture process zone. In this paper, digital image correlation (DIC) is used to put forward a new approach to measure the critical crack opening wc and therefore gain a new insight into the fracture parameters of bricks.