What is Intermediate hydration in concrete? Explain in details of Intermediate hydration in concrete with example.
Intermediate hydration is a stage of the concrete curing process where the concrete has partially reacted with water, but is not yet fully hardened. During this stage, the concrete is still malleable and can be molded or shaped, but it has already gained some of its strength.
Concrete is made up of a mixture of cement, water, and aggregates (such as sand and gravel). When water is added to cement, a chemical reaction known as hydration begins. This reaction causes the cement to harden and bind the aggregates together. The hydration process is a complex series of chemical reactions that can be broken down into several stages.
The first stage of hydration is known as the dormant period, where there is no visible change in the concrete. This is followed by the induction period, where the first signs of chemical reaction can be seen, such as the temperature of the concrete rising slightly. The next stage is the acceleration period, where the reaction rate increases rapidly and the concrete begins to set. The final stage is the deceleration period, where the reaction rate slows down and the concrete continues to gain strength over time.
Intermediate hydration occurs during the acceleration period, when the concrete is still malleable but has already gained some of its strength. At this stage, the concrete can be shaped and molded, but care must be taken not to damage it, as it is not yet fully hardened. For example, if concrete is poured into a mold, it can be removed from the mold during intermediate hydration, but it must be handled carefully to prevent cracking or other damage.
It’s worth noting that intermediate hydration can vary depending on factors such as the type of cement used, the water-to-cement ratio, and the temperature and humidity of the curing environment. As such, it is important to follow best practices for curing concrete to ensure that it reaches its desired strength and durability.