Pigments

For the full colors of concrete, should be in addition to the white cement and neutral color filler add pigments. These include pigments, cement, ie those which can be added and mixed with cement. Basically, at the moment most of the pigments used industrially (inorganic) obtained in the process, and not from natural sources (organic). The main component of most colors for inorganic pigments are iron oxides in various proportions. In some shades of red they represent almost 100% of the composition. Exceptions are basically

• whites - or titanium oxides,
  
• greens - chromate, chromium oxides,
  
• blue - cobalt oxides.
  

An important feature is their resistance to UV radiation, which is how the sun "eats" color over time. It means that you must before buying or using to learn this from the manufacturer. This is very important if the concrete, which uses such a pigment is to be exposed to the outside.

Basically, the amount of pigment added to the concrete defined proportions by weight relative to the quantity of cement (note - each pigment has its weight measured in the bulk density or weight of any individual volume (eg. m3), and means they are not equal nor even similar). Most manufacturers refer to the maximum quantity of approx. 5% relative to the cement. This is because of this that, after a certain threshold of the addition of the pigment does not increase the strength of color, but only weakens the concrete.

During those are the use of pigments should be aware of very important principles:

• change in the amount of the pigment in the mixture strength will change color, indicating that another mixing color will vary. For this reason it is important to precise dosing.
  
• change in the amount of pigment of the unit does not change the strength of the color of ready-mix on a similar scale. Initially the changes are very large fluctuations in the relatively small amounts of pigment to the large amount of color saturation of the pigment to cause visible change was large.
  
• lime - itself "eats" the strength of pigment in the mortar or plaster, which means that what the manufacturer, can not go out "in practice".