Hydration on Concrete

                 When the aggregates, water, and the cement are combined, the mixture starts to harden. This harden process begins when the water is added with the cement this reaction is called hydration. During this reaction a node forms on the surface of the concrete. It expands till connecting with another node on the other cement particles.
                  Curing begins after the exposed surfaces of the concrete have hardened sufficiently to resist marring. Curing ensures the continued hydration of the cement so that the concrete continues to gain strength. Concrete surfaces are cured by sprinkling  with water or by using moisture retaining fabrics such as burlap or cotton mats.
                  Concrete continues to get stronger as it gets older. Most of the hydration and strength gain takes place within the first month of concrete's life cycle, but hydration continues at a slower rate for many years.