White Portland cement is similar to grey Portland cement, however differs in fineness and colour, the white colour is determined by its manufacturing process and its raw ingredient.
This cement is made from raw materials with little iron or manganese, China clay is usually used in white cement with limestone or chalk.
Also allows multiple color options for the production of cement architecture and structural concrete.
Introduction to White Portland Cement:
White cement concrete is also known as Snow Crete.
White cement is available throughout North America, with many American Society for Testing Materials ASTM confirming the manufacturing process of white cement.
Properties of white cement concrete:
- The initial setting time is 100 minutes.
- The fineness of white cement is 395 kg / m 2.
- The brightness of white cement is 87%.
- The compact density of white density is 3150 kg / m3.
- The bulk density of white cement is 110 kg / 3.
- Compressive strength after 1 day 21 MPa, 2 days 38 MPa, 7 days 61 MPa and 28 days later 74 MPa.
The raw ingredients for white cement concrete:
White cement is supplied in both bulbs and bags.
White cement bags should not be placed in direct contact with the ground.
The white cement bags should be stored in pallets and kept away from the ground to protect them from the weather.
White cement can be stored for a minimum of 6 months when kept in a suitable dry condition due to the low content of soluble chromium in white cement.
Aggregates should be selected for white cement including white marble, white granite, and crushed calcinated flint.
The color choice of coarse anklets is important in the final appearance and look of white concrete.
The selection of fine aggregates especially the filler particles less than 0.25mm.
Special care is taken to ensure that the mixture of aggregates is continuous to avoid shading of the finished products.
Water used for mixing white concrete should be clean and free of organic impurities.
The water-cement ratio is higher for white concrete than for normal concrete and is important in determining the ultimate strength of concrete.
ASTM specification for white cement as follows:
- The cement has to be white Portland cement which conforms to the standard specification (ASTM C150).
- White cement is more expensive than ordinary Portland cement because of modifications within the manufacturing process and the materials used.
- The price of white cement is 4 times greater than ordinary Portland cement.
- The compression strength of white cement is lower than OPC cement.
- A considerable amount of iron and manganese are added in its manufacturing process to extend the whiteness of the cement.
- White cement produces concrete with uniform and ideal colour to structure as a result of the colour of the structure is extra necessary from the perspective of a structure.
- White cement production usually requires 40% more energy than normal grey cement, this affects the high price of white cement.
- Light colored sand with white chalk is used in the production of white cement and special precautions should be taken during the manufacturing process of white cement.
- Mix designs for white or colored concrete are designed based on the effect of each component on the color of the concrete:
- Pigment and type supplements.
- Type and color of cement.
- Dosage of admixture.
- Type, gradation, color, and cleanliness of fine and coarse aggregates.
- Constant ratios, especially maintaining a uniform water-cement ratio.
Advantages of White Portland cement:
- This cement is used in architectural decorative and design purposes.
- It provides better surface finishing.
- It can be used for Tile grouting and crack filling.
- These cement are Water proofed.
Disadvantages of White Portland cement:
- They are expensive than regular OPC.
Uses of white cement:
- White Portland cement is used for decorative works and prestige construction tasks.
- White cement is used to provide brightly coloured concrete and mortar
- It is used for interior and exterior decoration due to its whiteness.
- White cement is used in roads to increase the average visibility of the highway.
- It is used for precast members for manufacturing large numbers.
White cement concrete makes the floors that reflect more light than normal light gray concrete floors reducing the energy required for interior lighting.
The reflectivity is particularly striking in wet climates as gray concrete becomes darker when moist.