How to Properly Dose Pigments in Cement, Mortar, and Concrete
Coloring cement with powder pigments is a well-established technique in architecture and construction. It is essential to apply the correct dosage in each case to achieve the desired shade. In this article, we explain how to properly dose pigment when mixing it with pure cement, concrete, or mortar.
What is pigment dosage and why is it so important?
The pigment acts on the cement content of the mixture, so it’s important to know the exact amount of cement in order to calculate the right pigment dosage. The pigment ratio will determine the color intensity (softer or stronger) of the final product.
(For example, for a 4% dosage, you would add 4 kg of pigment for every 100 kg of cement.)
Dosage for:
1. Pure Cement:
- Dosage: A standard dosage ranges from 2% to 5%.
- Color Intensity: You can obtain many different shades from the same pigment reference. A higher dosage results in deeper, more vibrant tones; lower dosages produce lighter, softer shades.
- Recommendation: If you are aiming for very intense or dark tones, dosage can go up to 8%. However, note that beyond this percentage, color saturation is typically reached.
- White Cement: Lower dosages are usually sufficient since you’re starting from a white base, resulting in cleaner, pastel colors.
2. Mortar (sand and cement):
- Dosage: Typically between 0.5% and 1% of the total mortar weight.
- Considerations: The type and color of the sand can influence the final result. We recommend testing a sample with the specific mortar mix to be used.
- Note: Pigment acts on the cement content in the mortar. Depending on the mix, the mortar may contain more or less cement, so it’s important to consider this when adjusting pigment dosage.
3. Concrete (aggregates, sand, and cement):
- Dosage: Between 2% and 5% of the cement weight. In ready-mix trucks, a common dosage is 10 kg/m³.
- Applications: Pavements, architectural elements, walls, urban furniture.
- Considerations: Pigment dosage should always be based on the amount of cement in the mix. For correct dosing, it is essential to know the type of concrete and the amount of cement per m³.
Factors That Affect the Final Color
Several factors can influence the aesthetic outcome of pigmented concrete:
- Cement Type: White cements produce brighter colors; grey cements tend to dull the shades.
- Curing: Proper curing and consistent hydration are key for even color.
- Aggregates / Sand: These can alter the perception of the final color.
- Water-to-Cement Ratio: More water generally lightens the color.
Technical Tips for Ensuring Uniformity
- Always dose pigment based on the weight of the cement, not the total volume.
- Use precision scales for small quantities.
- It is advisable to perform preliminary tests using the same materials and proportions as the actual project.
Which Pigment Should You Choose?
SC Pigments® are premium-quality inorganic pigments specifically formulated for mixing with cement, mortar, and concrete. They comply with the UNE-EN 12878:2005 standard, ensuring durability and resistance to UV rays.
If you’re unsure how to dose pigment correctly for your mix, feel free to contact our technical team—we’re here to help.