How does concrete harden under water?

Concrete hardens under water through a process called hydration, where the water in the mix reacts with cement particles, forming chemical bonds that create a solid structure. This process can occur even when submerged, as long as there is sufficient water available for the reaction. The hydration continues over time, allowing the concrete to gain strength and durability, regardless of the surrounding environment. Properly mixed and placed, underwater concrete can achieve similar or even superior performance compared to concrete cured in dry conditions.