Grasim Answers

1. What is grade?

Grade is the 28 days strength when tested as per Indian Standards under standard conditions. If it is 33-grade cement then it has strength equivalent to 33 MPa (330 kg/cm2). Similarly 43 & 53 grades can be defined.

2. Know more about Ordinary Portland Cement…

Ordinary Portland Cement (OPC) is classified into 3 grades, viz. 33, 43 & 53 grades

Composition:

  1. OPC is produced by inter-grinding clinker with gypsum (approx. 3 to 4%)
  2. BIS permits addition of only upto 1% additive in OPC

Highlights:

  1. OPC is the basic binding material. It forms the base for production of PPC, PSC, etc…
  2. Production of OPC in India is approximately 56% of the total production of cement
  3. 33 grade is virtually phased out and has been replaced by 43/53 grades
  4. Trend is to use higher grades of OPC. However, 53 grade has reached to 55% of total OPC production in India
  5. Share of 53 grade is continuously increasing and 43 grade is decreasing


Details on different grades of Cement

SL.No
Grade of Cement
Details
1
33 Grade Ordinary Portland Cement(IS: 269 -1989)
  1. The compressive strength after 28 days is 33 N/mm2
  2. Used for general construction works in normal environmental conditions.
  3. Cannot be used where higher grade of concrete above M-20 is required.
  4. The use of this cement has progressively decreased and virtually phased out.
2
43 Grade Ordinary Portland Cement (IS: 8112 - 1989)
  1. Most widely used cement for general construction work.
  2. Minimum 28 days Compressive Strength -43 N/mm2.
  3. Used for construction of residential, commercial and industrial buildings, roads, bridges, flyovers, irrigation projects and other general civil construction works.
  4. Suitable for all types of applications - RCC, Plastering, Masonry5. Rajashree is the premium OPC 43 brand in the market giving strength of around 65 MPa at 28 days.
3
53 Grade Ordinary Portland CementIS: 12269 - 1987
  1. Introduced in 1991 by Grasim - Birla Super.
  2. Minimum 28 days Compressive strength - 53 N/mm2
  3. Gives 10-15% saving in cement consumption & 5-8% saving in steel consumption provided higher grades of concrete say M30 and above are used.
  4. Useful for high rise buildings bridges, flyovers, chimneys and pre-stressed structures where high grade concrete is required.
  5. Gives better durability characteristics to concrete -high grade concrete can be made with lower water cement ratio

4. What is 53-S cement?

Indian Railways was earlier using special grade cement complying to its specification no. IRS T-40 for manufacturing concrete sleepers. There was an amendment (no. 6) to IS 12269, IRS T-40 cement and then this was brought under the ambit of BIS. It is now designated as 53-S Ordinary Portland Cement and conforms to 53-S (IRS T-40) (IS: 12269-1987).

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