Heat of Hydration of Cement

The chemical reaction that takes place between the cement and water is referred as hydration of the cement. The hydration reaction is an exothermic reaction. The cement hydration will liberate a considerable amount of heat. This is called as Heat of liberation or Heat of Hydration. The mixing of cement with water will result in rapid evolution of heat that will last for few minutes. This evolution of heat is probably due to the reaction of a solution of aluminates and the sulfates. This rapid heat and reaction are depressed by the addition of gypsum. The Early heat of hydration is due to the hydration of C3S.

The hydration process is not instantaneous. The reaction is faster in the early stages and will go decreasing with the time period. It is observed that the complete hydration is possible only for cement particles that have a particle size smaller than 50 microns. With the increase in the fineness, there is an increase in the rate of hydration.

Features:-

• Initial Hydrolysis
• Induction Period or the Dormant Period
• Acceleration
• Deceleration
• Steady State
• Heat hydration of cement with water is exothermic
• Exothermic-an exothermic reaction is a chemical reaction that releases by light or heat
• The liberation of heat is called heat of hydration
• Study and control hydration becomes important in mass construction (like dams etc)
• Heat evolution due to the reaction of solution of aluminates and sulphates
• Fully-automatic test procedure
• Evaluation and documentation of test results via computer
• Rigid, durable measuring instrument for industrial and laboratory use
• Simple operation
• Self-calibrating