How is Concrete Colored?
Concrete dyes take many different forms and compositions and can be used on both residential and commercial concrete applications, including sound/retaining walls, bridges, countertops, floors, etc. Early concrete dyes consisted of generic printing inks that were dissolved in mild solutions of alcohol and applied to concrete surfaces to add a wide array of color to plain gray concrete. When alcohol-based dyes are exposed to sunlight, the color either lightens or fades out completely. Therefore, alcohol-based dyes were more prevalent in interior applications where direct sunlight or other forms of ultraviolet (UV) lighting was not present.
Manufacturers later began dissolving the same printing inks in different carriers, such as acetone, lacquer thinner and other solvents, hoping to achieve increased penetration levels. In addition, UV inhibiting agents were added to new dyes to help with the UV instability issues. However, slight fading (5-8% per year) still occurs when the dye is exposed to direct sunlight.
Concrete can be colored in many ways; color hardener, integral liquid or powder, and acid stains to name a few. The process of integrally coloring the concrete offers the advantage of the entire volume being colored; however, the surface strength is not increased as with the use of color hardener. Dry shake color hardener is another popular way to color concrete. You broadcast the hardener on the concrete as soon as it is floated for the first time. After letting the bleed water soak into the hardener you float and trowel it in. This method only covers the surface about 3/16 of an inch but it gives the concrete surface a longer wear life.
Adding base color:
The base color is the primary color used in stamped concrete. The base color is chosen to reflect the color of the natural building material. Adding a color hardener to the concrete produces the base color. Color hardener is a powder pigment used to dye the concrete.The color hardener can be applied using one of two procedures; integral color or cast-on color.
Integral color is the procedure where the entire volume of concrete is dyed the base color. Adding the color hardener to the concrete truck, and allowing all the concrete in the truck to be dyed color the entire volume of concrete. Cast-on color is the procedure where the surface of the concrete is dyed the base color. Spreading the color hardener onto the surface of the wet concrete and floating the powder into the top layer of the wet concrete color the surface of the concrete.
Adding accent color:
The accent color is the secondary color used in stamped concrete. The secondary color is used to produce texture and show additional building materials (e.g. grout) in the stamped concrete. Applying color release to the concrete produces the accent color. Color release has two purposes. Color release is a pigment used to color the concrete and color release is a non-adhesive used to prevent the concrete stamps from sticking to the concrete.The color release can be applied in one of two procedures based on the two forms it is manufactured in: powdered (cast-on color release made up of calcium-releasing powders that repel water); or liquid - which is a light aromatic-based solvent, spray-on color release. Cast-on color release is a procedure where the powder color release is applied by spreading the color release on the surface of the concrete before the concrete is stamped. Spray-on color release is a procedure where liquid color release is sprayed on the bottom of the concrete stamps before the concrete is stamped.
Acid Staining differs from concrete coloring via dyes and hardners due to a chemical reaction. Click Acid Stain to read about it!