White cement is the same as that of grey Portland cement but the only difference is in the colour and fineness. This colour of this cement is determined by its raw materials and the process of manufacture. In this article, we study the manufacture, properties, uses and difference of white cement.
Manufacture of White Cement
The manufacturing process of white cement is the same as that of grey cement, but the selection of raw material is an important part of the manufacturing process. The oxides of chromium, manganese, iron, copper, vanadium, nickel and titanium impart the grey colour to the cement. In white cement manufacture, these raw materials are kept to the least percentage.
Limestone and clay are used as a prominent raw material for the manufacture of white cement. The manufacturing process is the same as that of OPC cement, the only differences are the heat required for the burning of raw material is more and fineness is more.
Following Raw material are used to make white cement
1- Lime Stone -High Carbonate & Low Iron.
2- Clay – High Alumina and Low Iron
3- Oil / Pet Coke / Rubber
4- Gypsum / Salenile
Properties of White Cement
|Setting Time||100 min|
|1 day||21 MPa|
|2 day||38 MPa|
|7 day||61 MPa|
|28 day||74 MPa|
|Compact Density||3150 kg/m3|
|Bulk Density||1100 kg/m3|
Uses of White Cement
1- Used for prestige construction projects and decorative works.
2- Used for coloured concrete with the use of inorganic pigments to produce brightly coloured concretes and mortars.
3- Due to its whiteness, it finds its application in architectural beauty, interior and exterior decorations, floorings, ornamental concrete products such as idols while grey cement is mostly used for construction purposes.
4- Used inroads due to the property of high reflectiveness to add visibility to highway medians.
5- White cement is also used in a high amount for manufacturing precast members. Beautiful precast members are made utilising the white Portland cement.
6- They are also used widely for making cast stones of appealing appearance.
7- White cement is comparatively a costly cement type and is, therefore, used only selectively.
Differences between White Cement and Grey Cement
|Properties||Grey Cement||White Cement|
|Raw Materials||Raw materials contain a high amount of Iron Oxide and Manganese Oxide.||Raw materials contain a very little amount of Iron Oxide and Manganese Oxide.|
|Fineness||Usually less fine than white cement.||Usually finer than grey cement.|
|Kiln Fuel||Coal, petroleum coke, fuel oil, natural gas.||Oil is used to avoid contamination by coal ash.|
|Cost||Less expensive.||Expensive than grey cement.|
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