Hydration of cement is an exothermic process that produces large quantity of heat.
In mass concrete structures such as dams, retaining walls, bridge abutment, raft and etc. the rate of dissipation of heat of hydration from the surface is much lower than that generated.
It causes rise in temperature inside the concrete mass and may develop thermal and shrinkage cracks. Under this circumstances, the low heat cement or can be effectively used.
For low heat cement, the rate of heat evolution is slow initially, so both setting and hardening rates are slow initially.
But in the later stage, both rates are faster than the Portland Cement (OPC).
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