Color hardeners come as powders that are hand broadcast onto the freshly placed concrete and then worked into the surface with a float or trowel. They are easy to use and are available in an assortment of colors. They are different than integral color which colors the entire concrete slab, whereas, color hardeners pigment just the top layer and it tends to be a bit more intense than integral. They are often used in place of integral colors when more control of the final surface color is needed or when it is not practical to use integral color. They are fully compatible with other coloring products such as Walttools accent release, Tru Tique antiquing agent, Tru Tint stains, decorative sealers, etc.
Color hardener is a specialized colored overlay mix consisting of silica, cement, and pigment. The powdered color hardener is broadcast onto the surface, given time to absorb moisture, and is then floated into the concrete. It will actually strengthen slab surface by making it denser. This harder surface can improve the longevity against traffic and other environmental factors. For decorative contractors, color hardener provides the benefit of a richer cream top surface which takes texture better than just plain concrete.
Another benefit for color hardener is that there are colors available that are very expensive if choosing integral colors since integral color colors the entire slab and with color hardener you are only coloring the top 1/8 inch of the surface. More than one color of hardener can also be used to create a more dynamic surface.
The factors to consider when choosing color hardeners for your stamped concrete projects are that it creates alot of dust(messy) and that if the slab chips deep enough, the plain concrete underneath is exposed. Chips can be corrected by using a pasty mixture of color hardener and water.
How to use concrete color hardener. Place, vibrate and float the concrete surface according to standard ACI recommendations. Cover or protect adjacent surfaces. Do not power float or trowel the surface. Apply dust on color hardener in two coats, using a dry shake method of uniformly broadcasting the product onto the surface of the freshly placed concrete. Following the initial floating, when excess moisture is no longer evident, broadcast approximately 2/3 of the dust on color hardener onto the fresh concrete surface. Float the broadcasted material into the surface with a mechanical or manual float after the color hardener achieves a uniform moistened appearance. Do not steel trowel. When the water sheen has again disappeared, broadcast the remaining 1/3 of the color hardener onto the surface at right angles to the initial application. Float the second application as above. Retain a small amount of material to correct areas that have insufficient color depth. After the surface has achieved proper firmness, apply a broomed, scored, textured or trowel finish. A mechanical troweling machine may be used for final finishing. Do not over trowel.
Avoid using plastic sheeting, membrane paper or moist curing methods. After seven days, seal with your favorite Walttools Stampsheen sealer.