Cement Grades in India

In India, according to government regulations, the cement industries follow three types of grades they are 33, 43 and 53

How are the Grades Calculated?

Grades are calculated depending on the crushing strength. A cement mortar cube with a surface area of 51㎠ having a size of 70.71mm was tested for 28 days and decided their grades.

Different Types of Cements

There are many types of cement used in construction in India. Let us look at them.

Ordinary Portland Cement (OPC): 

• This type of cement is used for flooring, plastering, and masonry. OPC cement is Ordinary Portland Cement, and it possesses low compressive strength, and its low heat hydration ensures minimal cracks. OPC can be used up to M20 grade concrete. 
• Indian standard code (IS) is 269- 1976
• It is available in grades- 33,43,53 in the market.
• The compressive strength lies between 33-53MPa for 28 days, 22- 27 MPa for 7 days, and 16 -27MPa for 3 days of curing after casting.

Portland Pozzolana Cement (PPC)

In this cement, there are two types: Calcined based and Fly ash based. It is equivalent to 33-grade cement.

Portland Pozzolana cement (calcine-based):

This cement is blended with calcine and called blended cement. The compressive strength is low, and it has high fitness. Generally, it is used in grouting cable ducts, plastering, and flooring. In adverse soil conditions, it is used as a corrosion resistor so concrete can be long-lasting. Ordinary Portland cement can substitute it.

• Indian standard code (IS) is 1489 P-2
• The compressive strength for 28 days PPC is 33MPa, and for 7 days, it is 22MPa, and for 3 days 16MPa of curing after casting.

Portland Pozzolana Cement (fly ash based):

This cement is blended with Fly ash and has properties of Fly ash and cement. It is also used where calcine based cement is used. Its compressive strength is low. It is not readily available in the market like regular cement.

• Indian standard code (IS) - 1489 P-1

Portland Slag Cement (PSC)

• Portland Slag cement has high concrete strength. It does not crack easily, so it is used to construct bridges and houses in hard environments like marine and wastewater flowing areas. It is preferred over ordinary Portland cement for its high strength and long-lasting nature. It is resistant to chemicals like sulphate and chloride and light corrosion.
• The Indian standard code is -455
• The compressive strength for 28 days is 33MPa, for 7 days 22MPa, and 3 days 16MPa 

Rapid hardening cement (RHC)

• Rapid Hardening Portland Cement contains more clinker tricalcium silicate (c3s). It has high hardening strength, hardens quickly, and takes less time to settle. It is used when there is limited time in construction. It has a similar strength to OPC.
• The Indian standard code is 8041-1990

Low Heat Cement

It consists of lower C3A, its contents, and Dicalcium silicate contents (C2S). The rate of settling is a bit lower than OPC. It is used in massive constructions. 

• The Indian standard code is 269-1976.

Hydrophobic Cement:

It is considered mainly for waterproofing constructions. This type of cement is used to construct dams, underwater constructions, spillways, and railway bridges on lakes. The cement settling rate is initially slow but will increase eventually.

• The Indian standard code is 8043.

Sulphate Resisting Portland Cement (SRPC):

• SRPC or Sulphate Resisting Portland Cement is mixed with C3A (less than 5%) and 2C3A +C4AF (less than 25%). It is also a type of portland cement. It is mainly used in structural concrete.
• Its compressive strength is 33MPa (for 28 days after casting)
• The grade of SRPC is 32.5 and 42.5

Super Sulphated cement (SSC):

• Super Sulphated Cement is formed from portland cement (1-2%), blast furnace slag (80-85)%, calcium sulphate (10-15%) and is made like fine granules like portland cement. 
• The Indian standard code is:6909
• It is used in marine works, and RCC pipes are used in sulphate-bearing soils.
• Its qualities include resistance to sulphate and low heat of hydration.
• The compressive strength after casting for 28 days is 30MPa, and for 7 days it is 22MPa, and for 3 days it is 15MPa. 
• The grade of SSC is 33