What is Cement ?
Cement is generally known as ‘Portland Cement’ in civil engineering works. It is generally used as a binding material, which sets well and hardens quickly under water and gives the desired strength. The purpose of each grades of cement is same, that is to bind the materials used in concrete.
The various types of constituents which makes cement are :
- Lime – 63 %
- Silici – 22 %
- Alumina – 6 %
- Iron Oxide – 3 %
- Magnesuim Oxide – 2.5 %
- Sulpher Trioxide – 1.5 %
- Loss of Ignition – 1.5 %
- Alkalies – 0.5 %
The ratio of these constituents matters a lot while manufacturing cement. More or less of these ratio can damage the quality of the portland cement.
The manufacturing process of cement consist of grinding the raw materials and mixing them in proposed proportions. These mixture is then burnt in large rotary kiln at the temperature of 1500°C, till the clinkers are obtained out of it.
These clinkers then cooled down and grounded to fine powder with sufficient amount of gypsum and the final product is called as ‘Portland Cement’.
Different Grades of Cement
Grades of Cement denotes the average compressive strength of cement after 28 days of setting. It is represented in Mega Pascal (MPa) or Newton per millimeter square (N/mm²). These compressive strength are generally carried out on concrete cubes made out of different grades of concrete.
The different grades of cement are :
- 33 grade
- 43 grade
- 53 grade
|Compressive Strength (N/mm²)||IS: 269-1989|
|After 3 days||16||23||27|
|After 7 days||22||33||37|
|After 28 days||33||43||53|
Grade 33 :
In 33 grade of cement, the compressive strength of cement after 28 days of setting is 33 MPa. This type of cement is used for general construction works such as plastering, flooring, grouting of cable ducts and pre-stressed concrete works etc. As the construction methods are upgrading, so are the construction materials. Due to availability of higher grades of cement, this grade of cement is rarely used.
Grade 43 :
In 43 grade of cement, the compressive strength of cement after 28 days of setting is 43 MPa. This type of cement is used for plain concrete work, plastering, pathway etc. These grade of cement is not used in the construction work where rapid setting is needed.
Grade 53 :
In 53 grade of cement, the compressive strength of cement after 28 days of setting is 53 MPa. This type of cement is used for reinforced cement concrete, roads, pre-stressed concrete etc. Generally 53 grade of cement is most commonly used in construction work. The setting time of this grade is comparatively faster than other 2 grades of cement.
Also Read : Different Types of Grades of Concrete