Decorative concrete is the use of concrete as not simply a utilitarian medium for construction but as an aesthetic enhancement to a structure, while still serving its function as an integral part of the building itself such as floors, walls, driveways, and patios.
The transformation of concrete into decorative concrete is achieved through the use of a variety of materials that may be applied during the pouring process or after the concrete is cured, these materials and/or systems include but are not limited to stamped concrete, acid staining, decorative overlays, polished concrete, concrete countertops, vertical overlays and more.
Concrete statues are made by pouring concrete into a latex mold. Often painted and sold for garden ornaments. Most popular designs are bird baths and garden gnomes.
As a modern technique, stamped concrete is the process of adding texture and color to concrete to make it resemble stone, brick, slate, cobblestone and many other products found in nature including wood, fossils, shells and many more. This limitless array of possibilities combined with great durability and lower cost than natural products makes Stamped Concrete an easy choice for new construction and renovation projects.
The installation consists of pressing molds into the concrete while the concrete is still in its plastic state. Color is achieved by using dry shakes, color hardeners, powder or liquid releases, integral colors, or acid stains. All these products may be combined to create even more intricate designs.
Stamped concrete may be used on driveways, patios, commercial roads and parking lots and even interior floors. Stamped concrete is a desirable finish to concrete areas, however with time and wear the color dyes fade and the surface looks patchy and unpresentable. There are many re-coloring options which can completely restore and rejuvenate the color and presentation of faded stamped concrete.
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.
Colored concrete can be obtained from many ready mix concrete companies and many have color charts available.
Acid staining is not a dyeing or pigment-base coloring systems, but a chemical reaction. A mixture of water, mineral salts and a slight amount of muriatic acid is applied to the concrete surface. This chemical reaction with the existing minerals (primarily lime) in the concrete over a period of one to four hours creates new earth tone colors on the concrete surface. The concrete surface is later scrubbed to remove excess stain and neutralized by a basic solution of ammonia and water or baking soda (less likely to cause whiting later) to help raise the ph level back to normal level. Due to inconsistencies in the surface level of concrete floor, acid staining creates a variegated or mottled appearance that is unique to each slab. The color penetration ranges from 1/16 to 1/32 of an inch. Older exterior concrete surfaces may not color as well as interior surfaces because the environment has leached or percolated out the mineral content. As well, any exposed aggregate (rocks) in worn concrete will not accept staining.
Chemicals commonly used in acid staining include hydrochloric acid, iron chloride, and sodium bicarbonate.
Water based stains are similar to acid based stains in the sense that one can still achieve a translucent look like acid; some stains are able to achieve an opaque color and/or a translucent effect. The main difference is that acid stains react to the concrete and change the physical make up of the concrete material, whereas water based stains are more of a “coating” that bonds with the concrete. There are many variations of water based stains that have come into the decorative concrete industry that perform in a number of different ways. Some are polymer based, acrylic and epoxy.
Polymer cement overlays, consisting of a proprietary blend of Portland cements, various aggregates and polymer resins, were introduced over 20 years ago. The purpose of adding a polymer resin to the cement and aggregate is to greatly increase the performance characteristics and versatility of conventional cements, mortars and concrete materials. Unlike conventional cement and concrete mixes, polymer cement overlays can be applied thinly or thickly without fear of delamination or typical product failure. In addition, polymer cement overlays are much more resistant to damage from salt, petrochemicals, UV, harsh weather conditions and traffic wearing.
Originally intended for use as a thin surface restoration material for concrete substrates, polymer cement overlays were introduced into the architectural concrete and commercial flooring industries in the early 80s. Subsequently, its use in these industries has become standard. Polymer cement overlays are regarded as economical in providing long term, durable renovation without the need for costly and continuous repairs associated with deteriorating concrete surfaces.
Rubber imprinting tools (stamps) are impressed into thin pre-mixed concrete overlay material shortly after it is placed to create natural stone or brick textures. These rubber imprinting tools are manufactured from molds created from authentic stone or wood. Release agents are used to help release the stamps from the concrete without sticking. Release agents come in either a liquid or powder form and are available in a wide range of colors.
