Material properties influencing early cracking of concrete

Maintenance free service life of concrete structures is often limited by crack formation. Hygral and thermal gradients are most often the origin of cracks in concrete. On the basis of a numerical model it is shown that optimum values for different material properties such as moisture diffusivity, coefficient of shrinkage, elastic modulus and fracture energy, have to be identified in order to avoid cracking. Combinations of these material properties, which certainly lead to crack formation, are determined. Numerical results are verified by means of an instrumented ring test. A combination of properties of concrete, which will certainly not lead to crack formation, is obtained. Results are compared with properties of conventional concrete. This approach can be extended to take into consideration thermal cracking and combinations of hygral and thermal stresses.