Grade of cement is the 28 day compressive strength when tested as per Indian standards under the standard conditions. The ordinary portland cement can be classified into 3 grades. viz. 33, 43 & 53 grades.
|Fig:1. 53 Grade Cement|
It means that a cement with 33 grade will have strength that is equal to 33 Mpa (330 kg/cm2). Similarly 43 & 53 grades will have 43 and 53 Mpa strength respectively. The 33 grade is virtually phased out and has been replaced by 43 and 53 grades of cement
The details of different types of cement grade are explained below
33 Grade Ordinary Portland Cement ( IS: 269 - 1989)
The compressive strength after 28 days is 33N/mm2. It is used for general construction works in normal environmental conditions. It cannot be used where higher grades of concrete above M20 is required. The use of this cement has progressively decreased and virtually phased out.
43 Grade Ordinary Portland Cement (IS: 8112 - 1989)
Most widely used cement for general construction work. Minimum 28 days compressive strength 43N/mm2. It is used for construction of residential, commercial and industrial building, roads, bridges, flyovers, irrigation projects and other general civil construction works. Suitable for all types of applications -RCC -Plastering and Masonry. Rajashree is the premium OPC 43 brand in the market giving strength of around 65 MPa at 28 days.
53 Grade Ordinary Portland Cement (IS: 12269 - 1987 )
Introduced in 1991 by Grasim - Birla Super. Minimum 28 days compressive strength of 53N/mm2 gives 10-15% saving in the cement consumption and 5-8% saving in steel consumption provided higher grades of concrete say M30 and above are used. Useful for high rise buildings bridges, flyovers, chimneys and pre-stressed structures where high grade concrete is required. It gives better durability characteristic to the concrete. With the help of 53 grade cement high grade cement with water cement ratio can be created.
Difference Between 43 and 53 Grade Cement
Initial Strength: 53 Grade cement are used for fast paced construction were initial strength is to be achieved quickly. 53 Grade cement has fast setting compared to 43 grade cement. 53 Grade attains 27 mpa in 7days compared to 23 mpa by 43 grade cement.
Uses & Application:53 Grade OPC cement is Used in RCC and prestressed concrete of higher grades, cement grouts, instant plugging mortars etc. where initial higher strength is the criteria. 43 Grade OPC Cement are commonly used for plastering works, Non-RCC structures, pathways etc where initial setting time is not of importance.
Prices:53 grade cements are 2-3% costlier compared to 43 grade cement.
Brands:Birla Cement, Ultratech Cement, ACC Cement, Zuari Cement, Coramandel Cement, Ramco Cement, Dalmia Cement are some of the well known brands in Southern India.