Heat of Hydration is the heat released during which process?

• A. During the hardening of concrete, heat is given off by the chemical process in hydration
• B. Heat produced by weather exposure
• C. Heat released when water is added to metal
• D. Heat caused by cement drying

Answer: (A)

Heat of hydration is the heat released during the chemical reaction between cement and water as it hydrates and hardens. When cement meets water, exothermic reactions form compounds like calcium silicate hydrate and calcium hydroxide, releasing energy as heat. This rise in temperature occurs during the setting and hardening of concrete, and can be significant in large pours. It isn’t caused by weather, drying, or simply adding water to metal; it’s fundamentally the chemical heat from the cement-water reactions.