White Portland Cement (WPC)
is made with raw ingredients that have low iron and magnesium content – two elements determining cement grey tint. White Portland cement
has the same properties as grey cement, except for colour, which is determined by its raw materials and the manufacturing process and after adding tints become clear and bright. Different colours of concrete can be created and to achieve wider colour range two or more pigments can be combined. Greater variety of decorative looks, as it is typically confined to architectural application, can be achieved by using coloured aggregates and varying the surface finish treatment or texture. WPC is also used for basic cement research because of the iron and magnesium lack which improves the resolution of nuclear magnetic resonance (NMR) measurements.
Mix designs for white or coloured concrete are formulated based on each ingredient’s effect on concrete colour:
- Type and colour of cement
- Type and dosage of pigment
- Type and dosage of admixtures
- Type, gradation, colour, and cleanliness of fine and coarse aggregates
- Consistent proportions, especially maintaining a uniform water-cement ratio.
A key advantage of using white cement for decorative and architectural concrete is that it provides a neutral tinting base and consistent colour results. Every colour option is possible with it, from pure whites to bright and pastel colours. For every architectural project, once a mix design has been developed, sample panels should be built at the job site. These mockups serve as references for colour and overall surface appearance.