Low Heat Cement | Properties | Advantage | Disadvantage
Cement hydration is an exothermic process that produces a large amount of heat during hydration.
The formation of cracks in the large mass of concrete due to the heat of hydration has called the attention of concrete technicians to produce a type of cement that produces less heat or the same amount of heat. low index in the hydration process.
Cement containing this property was purchased during the 1930s by the US and developed for use in mass concrete construction, such as dams, where the temperature is greatly increased by the heat of hydration.
Low-temperature evolution is achieved by reducing the C3S and C3A contents, which generate the maximum heat of hydration of the compounds and increase C2S.
Reducing the temperature reverses the chemical hardening reaction and further restricts the rate of heat evolution.
The heat evolution rate is low and the heat evolution is spread over a long period of time.
Therefore, the characteristic of low-temperature cement is the slow rate of energy gain. But the ultimate strength of low-temperature cement is the same as that of ordinary Portland cement.
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The hydration of low-temperature Portland cement according to the Indian standard specification should be as follows:
7 days – no more than 65 calories per gram.
28 days: no more than 75 calories per gram.
The specific surface area of low-temperature cement is not less than 3200 cm2/g according to the air permeability method.
The 7-day capacity of low-temperature cement is not less than 16 MPa in contrast to 22 MPa in the case of ordinary Portland cement. Other characteristics, such as setting time and sound, are similar to regular Portland cement.
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Properties of low heat cement
- Low heat hydration is 20% lower than OPC cement.
- Reduce the amount of water needed for hydration.
- Greater viability is obtained because the concrete is in liquid form
- Good volume stabilization.
- The initial potential is low but the ultimate strength is the high growth rate.
- The greater technical strength of concrete.
- The best effect is erosion.
- Excellent wear resistance.
- Low-temperature upward value of heat insulation.
- Super-high performance of chemical corrosion resistance.
- Excellent resistance to drying shrinkage.
- Better resistance to rupture.
Advantages of low heat cement
- Helps reduce the likelihood of thermal cracks in thick concrete sections.
- Improved durability performance.
- Excellent performance, such as high-end strength, sulfate corrosion resistance, good durability, good resistance to rupture, anti-seepage.
- Increased feasibility and pumpability with large pours in hydraulic engineering concrete and marine concrete work.
- The concrete strengths of the later ages have been significantly improved.
Disadvantages of Low Heat Cement
- The initial strength is less than that of OPC concrete, but the ultimate strength is the same as that of OPC.
- This cement cannot be used in cold weather.
- Cement is more expensive than ordinary cement.
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