Color Matching Concrete Part 2: Why Doesn't My Color Match?
There are a number of reasons integral color jobs may not be the same. Here are just a few possibilities that may explain the color variation:
Different mix designs are going to be a common culprit. Every component of the concrete – not just the pigment – will affect final color. White cement will result in a lighter shade while gray cement will be shaded darker. The color of sand and/or aggregate will also affect final color. Water content of the concrete can lighten or darken color. Some admixtures can even affect the final color of the concrete. If any one factor is altered, it can change the appearance.
Finishing technique is another common element that affects color. Hard troweled concrete and broom finished concrete may appear to have a different shade, even if the same mix design and pigment loading are used. Other placement and finishing elements, such as added water and subgrade condition, also have the potential to change final color and appearance.
Poor pigment selection will obviously result in a bad color match. It isn’t always as simple as making the wrong selection, however. Poorly calibrated or malfunctioning color equipment may be responsible for dosing the wrong color. Miscommunication can also lead to the wrong pigments being used on a job. For example, if the contractor and ready mix producer are not operating off the same color card, it can lead to confusion.