Low Heat Portland Cement (IS:12600)
Low Heat Portland Cement (IS:12600) To limit the heat of hydration of low heat Portland cement (LHC), the tricalcium aluminate component in cement is minimised and a high percentage of dicalcium silicate and tetracalcium alumino ferrite is added. The heat of hydration should not be more than 272 and 314 J/g at the end of 7 and 28 days respectively. The rate of development of strength is slow but the ultimate strength is same as that of OPC. To meet this requirement, specific surface of cement is increased to about 3200 cm2/g.
Properties: Less heat is evolved during setting low heat Portland cement. When tested by Le Chatelier method and autoclave test the expansion should not be more than 10 mm and 0.8%, respectively. The minimum initial setting time should not be less than 60 minutes, and the final setting should not be more than 600 minutes.
The compressive strength should be as follows.
72 ± 1 hour 10 N/mm2
168 ± 2 hours 16 N/mm2
672 ± 4 hours 35 N/mm2Uses: It is most suitable for large mass concrete works such as dams, large raft foundations, etc.