Investigations into fracture of carbonated concrete

Parameters that describe the fracture of materials (e.. fracture energy) are essential for mechanical calculations and simulations that apply the finite-element method. There are very few published values of the fracture energy of carbonated concrete specimens. However, by means of a wedge splitting test that can be performed on tablet-like specimens, determination of valid material parameters of the fracture behaviour of carbonated concrete is possible. This paper reports on the fracture energy of two different concrete specimens (with and without the addition of calcium chloride) stored either in air or carbon dioxide. The ratio of the notch tensile strength of carbonated and uncarbonated concrete specimens at age 168 days was found to be about 0.9; the ratio of the specific fracture energies for these specimens was determined to be 0.7. The characteristic length determined at 84 days on specimens that were stored either in air or in carbon dioxide was similar for both concrete types. Sensitivity to fracture or tendency to crack thus does not seem to differ regardless of concrete quality, whether carbonated or not.