What is the heat of hydration? What factors affect the rate of heat generation?

Heat of Hydration:

Heat of hydration is due to the heat released by the cement concrete while setting concrete with water and cement. The chemical reaction takes place in the concrete between the cement and water subjects to release some amount of heat from the structure. Type IV (Low heat of Hydration) cement releases low amount of heat where its strength of the structure will also grows slowly. Hence this type of cement is used for dams and bigger structures. But now a day the use of Type IV cement is reduced because the properties are achieved from the blending process in other types of cements.

Factors affecting rate of heat generation:

•  The components present in the cement such as tricalcium silicate, dicalcium silicate, and tricalcium aluminate affects the rate of heat generations.
• The physical property of fineness of the cement results in reaction between the cement and water. It will increase the rate of heat generation.
• Cement content, water-cement ratio, curing temperature, and chemical admixtures used also affect the heat development of the concrete.
• Higher the cement content in the concrete will develop more heat.
• Water cement ratio effect is lower than the effect of higher cement content.
• Mineral admixtures like fly ash will reduce the heat generation by the concrete.