COLORS

SIMILAR AND NOTEWORTHY ADMIXES

Matching and adding colors to a concrete mix involves selecting pigments and incorporating them into the mix to achieve a consistent and desired hue. Here’s a step-by-step description of how it's typically done:

1. Selecting the Pigment

Concrete can be colored using various types of pigments:

• Iron oxide pigments (most common): for earthy tones like red, brown, yellow, and black.
• Chromium oxide: for green hues.
• Cobalt-based pigments: for blue tones (less common and more expensive).
• Titanium dioxide: used to create white or lighten other colors.

Pigments come in powdered, granular, or liquid forms and are selected based on:

• Desired color intensity
• Cost
• UV resistance
• Compatibility with the cement type

2. Color Matching

To achieve a specific color:

• Sample testing is done first. Pigment proportions are adjusted and trial batches are made to match the target color.
• A color chart or spectrophotometer may be used for precision.
• Factors considered include:
• Water-to-cement ratio
• Cement color (gray or white cement changes the base tone)
• Aggregate color
• Finishing technique and curing method

3. Mixing the Pigment

Once the color is selected:

• The pigment is weighed accurately, usually a percentage of the cement weight (typically 0.5% to 5%).
• Pigment is added to the dry mix of cement and aggregates to ensure even distribution before water is introduced.
• Consistency is key: mixing time and method must be standardized across batches to avoid color variations.

4. Pouring and Curing

• The colored concrete is poured and finished like standard concrete.
• Uniform curing is essential—uneven moisture loss can affect color.
• Curing compounds or wet curing methods help retain even coloration.

5. Surface Treatments (Optional)

To enhance or protect the color:

• Sealants may be applied after curing to enrich the color and protect against fading.
• Stains or dyes can be used post-cure to deepen or alter the hue if needed.