Example: Concrete
Volume reduction due to moisture release is termed shrinkage (mineral building materials). The ratio between initial and final dimension is the amount of shrinkage. There are 4 types of shrinkage denominated according to their cause:
Capillary shrinkage: Capillary action is responsible for water release (evaporation on the surface) of fresh and still processible concrete. Capillary shrinkage ends with the phase of plastic deformation. Thus, this process is also known as early (age) shrinkage or plastic shrinkage.
Chemical shrinkage: Chemical shrinking denominates the unavoidable volume reduction during the hydration process of mineral construction materials.
Drying shrinkage: Drying shrinkage means moisture release of hardened concrete to the outside. How much drying shrinkage influences the final dimension depends on several factors, as e.g. recipe, ambient humidity, temperature, dimensions of the structural element, etc. Drying shrinkage is the biggest problem regarding the quality of a structural concrete element. However, a careful and consequent after-treatment of the concrete can influence this process positively.
Carbonation shrinkage: Carbonation causes compaction of the hardened concrete. The resulting volume reduction has almost no influence on the final dimension of a structural concrete element.
