Civil Engineering - Concrete Technology - Discussion

Why? Explain it in detail.

When to use low heat cement - 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 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 low heat Portland cement can be effectively used.

In low heat cement, ingredients are proportioned in such a way that C3A and C3S are formed in less amount but C2S is formed in increased amount so that C2S and C3S collectively impart the same strength as Ordinary Portland Cement (OPC).

Dam construction will involve mass concreting where heat of hydration is the major concern which if not monitored will cause crack in the bulk of the dam which is undesirable, hence low heat cement is preferable in this type of concreting.