Low heat cement is a special tailored cement which generates low heat of hydration during setting. It is manufactured by modifying the chemical composition of normal Portland cement. In this article we discuss about the composition, properties, characteristics, uses and advantages of low heat cement.
Composition of Low Heat Cement
This special type of cement is same as that of normal Portland cement, with some percentage changes in the chemical compositions. This cement contains low percentage (5%) of tricalcium aluminate (C3A) and higher percentage (46%) of dicalcium silicate (C2S).
Properties of Low Heat Cement
Table 1: Properties of Low heat Cement
|Specific Surface Area||250 m2/kg Min|
|Initial Setting||60 minutes Min|
|Final Setting||12 hours Max|
|Compressive Strength at 7d||13.0 MPa Min|
|Compressive Strength at 28d||42.5 MPa Min|
|Breaking Strength at 7d||3.5 MPa Min|
|Breaking Strength at 28d||6.5 MPa Min|
|Heat of Hydration at 3d||230 KJ/kg Max|
|Heat of Hydration at 7d||260 KJ/kg Max|
Characteristics of Low Heat Cement
- Low heat of hydration is 20% lesser than that of OPC cement.
- The amount of water required for hydration is low.
- High workability is obtained as the concrete is fluidly in nature
- Good volume stabilisation.
- Initial strength is low but the high growth rate of final strength.
- More high technical strength of concrete.
- Excellent impact erosion.
- Excellent wear resistance.
- Lower temperature upward value of heat insulation.
- Super-high performance of chemical corrosion resistance.
- Excellent resistance to drying shrinkage.
- Good resistance to rupture.
Compatibility for Admixtures
Low Heat Cement is compatible with:
- Chemical Admixtures for Concrete.
- Supplementary Cementitious Materials for Use with Portland cement: Fly ash, Slag – ground granulated Iron blast-furnace, Amorphous silica.
Uses of Low Heat Cement
- To make the road and workroom surface of factories such as chemical plants and sulphuric acid factories.
- Majorly used in constructing dams large footings, large raft slabs, wind turbine plinths.
Advantages of Low Heat Cement
- Assists in minimising the potential for thermal cracking in thick concrete sections.
- Improvised durability performance.
- Excellent performances such as high final strength, sulphate corrosion resistance, good lasting properties, good resistance to rupture,anti-seepage.
- Increased workability and pumpability with large pours in hydraulic engineering concrete and marine concrete works.
- Significantly improved later-age concrete strengths.
- Resistant to sulphate attack on reinforcement majorly in concrete pipes.
Disadvantages of Low Heat Cement
- Initial strength gained is lower than that of OPC concrete, but the final strength is same as that of OPC.
- This cement cannot be used in the cold weather conditions.
- Cost of the cement is higher than that of Ordinary cement.