Effect of the water saturation of aggregates on the shrinkage induced cracking risk of concrete at early age

This work consists in studying the effect of the water saturation of aggregates on the development of shrinkage and the potential cracking risk of early age ordinary concrete. Different concretes were obtained from a given concrete mixture by changing only the initial degree of saturation of limestone aggregates. Three degrees of saturation were studied, namely: 0% (dry aggregates), 50% (partially saturated aggregates) and 100% (saturated aggregates). From the experimental results, the early age behaviour and the mechanical properties of the concrete strongly depend on the water saturation of aggregates. A relative cracking risk was estimated from a stress-based approach and experimentally assessed parameters. The potential risk of cracking of these different concretes was shown to be different. Even if the total water content is kept constant, the water remaining in the cement paste actually depends on the initial water saturation of aggregates. The early age behaviour of concrete and the development of its early age properties depend on the amount of added water during the mixing.