White ordinary Portland cement known as “White Cement” is one of the most important raw materials used in construction of a building. White cement with the exception of whiteness has same properties as Gray ordinary Portland cement has. It is as durable and strong as Gray ordinary Portland cement and has high degree of whiteness. White ordinary Portland cement should confirm to IS: 8042-1989.
Manufacturing of white cement
The manufacturing process of white cement is somewhat different from manufacturing process of gray cement. During manufacturing if metal oxides i.e. iron and manganese are added, they help in increasing the whiteness of cement. Because of change in manufacturing process and cost of raw materials, white cement is costlier than gray cement.
White cement due to its whiteness is mainly used for architectural beauty, interior and exterior decorations such as terrazzo tiles and floorings, ornamental concrete products such as idols and swimming pools etc.
These days a number of colored cements are available in the market. Colored cements have same properties as white cement has. Alternatively one can make colored cement of his choice by just mixing color pigment. To obtain brightly, colored concretes and mortars, inorganic pigments are added in white cement. When pigments are added with ordinary cement, they may produce attractive colors but they are somewhat dull. With white cement, bright reds, yellows and greens can be readily produced. Blue concrete can also be made at some more expense. The pigments may be added at concrete mixer to mix them uniformly. To secure uniform color, the pigments must be mixed very intimately with cement preferably in a ball mill.
Production of Different Colors with Pigments and White Cement
S. No. | Required Color | Commercial Name of Color |
Appropriate Qty. of Pigment (Kg. per bag of cement) |
1. | Grays Blue-Black & Black |
Germantown lamp black |
0.25 0.50 0.25 0.50 0.50 1.00 0.50 1.00 |
2. | Blue | Ultramarine Blue | 2.30 4.10 |
3. | Brownish Red to Dull brick | Redoxide of Iron | 2.30 4.10 |
4. | Bright Red to Vermilion | Mineral Turkey Red | 2.30 4.10 |
5. | Red Sand Stone to Purple Red | Indian Red | 2.30 4.10 |
6. | Brown to Reddish Brown | Metallic Brown (Oxide) | 2.30 4.10 |
7. | Buff colonial Tint and Yellow |
Yellow ochre or Yellow Oxide |
2.30 4.10 |
8. | Green | Chromium Oxide or Greenish Blue ultra-Marine |
2.30 4.10 2.70 ---- |
Note:
1. Only first quality lamp black should be used.
2. In case of carbon black, as it is light in weight it requires thorough mixing.
3. For general use Black oxide or mineral black is most advantageous. For getting black shade, use 5 kg oxide per bag of cement.
Specification of white cement
1. Fineness
There are following two methods to check fineness of Portland cement.
2. Soundness
Alternatively autoclave expansion should not be more than 0.5% when tested according to IS 269 of 1989.
4. Compressive Strength
After 28 days compressive strength of cement concrete mix for various types of cement concrete mix is following.
Compressive strength of cement concrete mix
S. NO. | Type of Mix | Ratio of Mix | Compressive strength |
1. | M 10 | 1:3:6 | 100 kg. Per cm square |
2. | M 15 | 1:2:4 | 150 kg. Per cm square |
3. | M 20 | 1:1.5:3 | 200 kg. Per cm square |
Note: Cement concrete cubes filled in above mentioned cement ratios should be tested after curing for 7 days and the strength of cement concrete should not be less than 70%.
S. No
Storage Period
Reduction in Strength
1.
Fresh cement
Nil
2.
Three months old
20%
3.
Six months old
30%
4.
12 Months old
40%
5.
24 Months old
50%