Drying shrinkage

Drying shrinkage is a consequence of loss of moisture from hardened concrete to the environment. Due to the emptying of the fine pores in the concrete a negative capillary pressure develops, which causes a volume reduction of the concrete. If the concrete shrinkage is restrained, tensile stresses develop in the concrete (restrained shrinkage). When the tensile stresses become higher than the tensile strength of the concrete, cracks are generated (Figure 2). Cracks have a relevant impact on the durability of a reinforced concrete member, since they facilitate the ingress of harmful substances.