Red Seal Concrete Finisher Practice Exam

Shrinkage in concrete primarily occurs as moisture escapes from the material during the drying process. When concrete is mixed, it contains a significant amount of water, which is necessary for the hydration process to occur and for the concrete to achieve its intended strength. As the concrete cures and hardens, that water gradually evaporates, leading to a reduction in volume. This loss of moisture is the key factor that contributes to shrinkage, as the solid components of the concrete contract as the water content diminishes.

While other factors such as temperature changes, admixture use, and mixing procedures can influence the overall performance and characteristics of concrete, they are not directly responsible for shrinkage due to the fundamental process of water evaporation. Temperature changes can impact the rate of evaporation, but the primary cause of shrinkage is the drying out of the concrete as moisture escapes. Therefore, the correct understanding of shrinkage is closely tied to the behavior of moisture within the concrete matrix.