Dry shake floor hardeners provide a denser, more abrasion-resistant surface to a concrete slab. By adding metallic oxide pigments, the contractor gets a harder and colored surface in one application. But while the concept seems simple enough, the science of producing color hardeners requires more attention to detail than would, at first blush, appear.

Most color hardeners are essentially alike: a mixture of color pigments, portland cement, and sand. Subtle differences in this simple formula, though, separate one manufacturer's product from another. Because color hardeners contain as much as 40 percent cement (more than twice that of regular concrete) manufacturers include additional ingredients to ensure a proper set. These typically include a plasticizer, a water-sequestering agent, and a retarder, says Joe Garceau of Butterfield Color. Without them the surface would dry up and crust over, affecting both the coloration and the abrasion resistance.

The subtle variations in color hardeners can also be seen in the sand, where size, shape, and composition are the most important factors. Most manufacturers use proprietary mixtures, says Garceau. Typically, they use various angular to sub-angular quartz grain sizes, though the composition depends on the source material. The objective is to create an interlocking framework of grains that aids in abrasion resistance while holding securely to the slab.

Color hardeners are ideal for detailed work, Garceau says, particularly in geographic areas where labor rates are low. They also provide an alternative to the washout fees for ready-mix trucks often incurred when using integral colors. In selecting a color hardener, Garceau suggests it should have good cover strength; should wet out easily, drawing moisture from the slab below; and should have a creamy finish, for smooth troweling.

To learn more about the color hardeners below, circle the corresponding reader service number and mail in the card.

Attractive, long-lasting finish

Stampcrete Color Hardener is specially formulated to be easily incorporated into durable, abrasion-resistant surfaces, providing streak-free vibrant colors and an attractive, long-lasting finish for any type of traffic. Available in 28 standard colors, it is long-wearing, easy to maintain, and resistant to the effects of freeze/thaw cycles and salts. Textured surfaces may be implemented with this system to give authentic appearance variations where applicable. Stampcrete International, 800-233-3298, www.stampcrete.com. Circle 4.

Improved abrasion resistance

Atlas Tech-Hard is a ready-to-use, high-performance, dry-shake floor hardener designed to provide an abrasion-resistant surface. Available in many colors, the product is a special blend of portland cement, natural silica aggregate, and proprietary admixtures. It provides twice the abrasion resistance of normal concrete and reduces surface dusting, spalling, and deterioration. Atlas Construction Supply, 877-588-2100, www.atlastechproducts.com. Circle 5.

Enhanced finishing

QC Color Hardener is a premium, premixed dry-shake product that simultaneously colors, improves finishing, and hardens freshly placed flat-work. Ideal for imprinted concrete, it is available in 25 standard colors and a limitless range of custom colors engineered to provide a durable, uniform, and permanent surface. Made from the highest quality ingredients, it is applied to freshly laid concrete where it forms a colorfast, abrasion-resistant surface. It can increase the compression strength of concrete surfaces by as much as 3000 psi. QC Construction Products, 800-453-8213, www.qcconprod.com. Circle 6.

Streak-free blend of pigments

Dynamicast Color Hardener is a ready-to-use, dry-shake material for coloring, hardening, and finishing new concrete floors, walks, driveways, decks, and other architectural or imprinted concrete. It is stocked in 10 different colors, ready for immediate shipment. It is a streak-free blend of pigments, portland cement, hard-graded aggregate, and other proprietary ingredients designed to harden, densify, and color concrete floors and surfaces both indoors and out. Dynamic Color Solutions, 800-657-0737, www.dynamiccolorsolutions.com.Circle 7.

Improved surface quality

Superstone Color Hardener is a mixture of limeproof, ultraviolet- and weather-resistant color pigment, cement, hard aggregates, and surface conditioning agents that improve the properties of the finished concrete surface. The product is ready to use and can be applied as a dry shake over freshly leveled and floated concrete. Use it for bright and deep color selections, for excellent wear resistance, and for superior concrete stamping characteristics. The surface becomes more durable and resistant to weathering and scaling from de-icing salts. Super Stone, 800-456-3561, www.superstone.com.Circle 8.

Twice as many colors

Add vibrant color to the surface of freshly placed concrete with L.M. Scofield's newly expanded line of Lithochrome color hardeners. This ready-to-use, powdered dry-shake product produces long-wearing surfaces ideal for pedestrian or vehicular traffic. Now available in twice as many color choices—including contemporary colors—it won't fade, resists abrasion, and works well with stamping or imprinting. L.M. Scofield Co., 800-800-9900, www.scofield.com. Circle 9.

Synthetic and natural pigments

Kolor Hardener, by Kover Krete, is made from pure synthetic and natural iron oxide pigments, blended with cement, quartz crystals, and surface conditioning agents for a lightfast, weather-resistant surface. It is an inexpensive way to add beauty, décor, and value to concrete flatwork, and is perfect for stamped concrete and both indoor and outdoor projects. Sixty pounds will cover 100 square feet for most colors. Contract Packaging, 407-246-7797, www.koverkrete.com. Circle 10.

From soft and subtle to bold and vibrant

Brickform Color Hardener is an engineered blend designed to bond with the concrete surface for a tough, abrasion-resistant hardscape. When properly applied and troweled into newly placed concrete, it forms a colored surface that is resistant to weathering, wear, and normal abrasion. The range of available colors can vary from soft and subtle to bold and vibrant. Hard-trowel or broom finishing can achieve the appearance of different tones or shading. Sand-blasting or acid washing can add more dimension. More dramatic results can be achieved with decorative scoring or sawcutting. Brickform, 800-483-9628, www.brickform.com. Circle 11.