Concrete is a versatile material that can be colored, polished, stained, even stamped with patterns. It can be seeded with colorful rocks or glass and polished to appear as terrazzo. These techniques can even be combined to create a one-of-a-kind pool deck.
Colored concrete is created either by integral color or topical colors. Integral color is mixed throughout the slab and is preferred for use as a base color on high traffic areas because if the top is ever chipped, the color still shows through. Topical coloring is done with colored hardeners, shake-on colors, acid staining, acetone dyes, and water based dyes.
Colored hardeners are powders that are spread onto freshly placed concrete and then troweled onto the top. Shake-on colors or colored form releases are often used with stamped patterns to add a subtle color variation to mimic natural stone or other materials.
Acid stains are unpredictable because they work by chemically reacting with the cured and hardened concrete. Because the reaction occurs in different concentrations, acid stained concrete tends to vary in intensity. Many people prefer this look because it is totally random, appearing more natural than one that is dyed. Acid stained surfaces must be neutralized and rinsed following the coloring process, so existing buildings, plants, and lawns must be protected during the procedure.
Acetone dyes are usually applied to highly polished floors. The flammability and volatility of acetone prevents it from being used indoors or in certain states (California, for example). Water-based dyes are also applied to polished floors. Their finish is usually translucent and gemlike. Colors can range from natural hues to bright reds and blues.
Stamped and Patterned Concrete
Concrete can be stamped with impressions so that it resembles wood, stone, bricks, or cobbles. The available patterns range from ashlar tile patterns, running bond pavers, wooden slats to a random stone texture. The patterns’ sizes also vary to fit the scope and scale of the space.
The base color can be integral or a troweled-in hardener. Various secondary colors can be shaken or sprinkled to add highlights before the stamps are applied. The coloring additives result in a dense and strong composition. This density makes staining of colored concrete difficult. Acid stains are the most effective, but only after 30 to 60 days.
Mechanically Finished Concrete
Both plain and colored concrete can be mechanically treated after the curing. Patterns can be cut and elements sandblasted, etched, ground, or polished. Highly buffed concrete can be extremely slippery when wet and should be treated with an anti-slip solution during or after installation. Sandblasted or etched concrete, however, has a gritty texture and is a safe choice around pools. Concrete develops a matte finish from sandblasting or acid etching.
Exposed aggregates are common around commercial pools. The exposed rocks have a rough texture, reducing the temptation to run on the pool deck. In a residential pool deck, however, the sharp rocks underfoot are undesirable. Much like the exposed aggregate pool finishes used under water, these surfaces can be lightly polished, which “tips” the stones, removing the sharp edges that cause discomfort—providing beauty, slip resistance, and ease of use. By mixing colored rocks or tumbled beach glass with an integrally colored concrete deck, a unique and personalized motif can be created.