One of the fastest growing markets for iron oxide pigments is decorative concrete. Iron oxide pigments (IOP) are the lifeline of decorative concrete and the means of architectural expression. Only IOP provides a combination of cost effectiveness, light resistance, durability and cement compatibility to make color concrete feasible. Although other types of pigments provide these properties, their cost is several times that of IOP. Even with the use of IOP, the cost of the pigment may be doubled over the cost of the ordinary concrete material, which means that other types of pigment are costly for 99% of the non-ferrous concrete projects.
The products used in decorative concrete are divided into five categories: IOP.
Color sclerosing agent
Coloring demoulding agent
The two concrete coloring methods are simple and easy to use. Directly added to the concrete mixer, the pigment is dispersed throughout the concrete load through the rotary mixing drum, thus coloring the whole concrete component. Pigments can be in the form of powder or water based dispersions (liquids). Powders are usually pre decomposed into self decomposition paper bags, so that pigments can be easily and accurately added to the field. The powder can also be added to the premixed plant.
Liquid is usually added to the mixing equipment by automatic coloring system. The advantage of the overall color is simple, and the entire panel, panel or structural member becomes the same color. This ensures surface damage and does not expose grey concrete below. The shortcomings of the specific installer include higher material costs and additional costs for cleaning up hybrid cars although many premixing companies are abandoning the cost. According to the required color intensity, the amount of IOP used in a typical 4 inch slab can range from 5 to 25 pounds / 100 square feet.
The second method used for coloring the slab is to use a color hardening agent, sometimes called dry shake. The color curing agent is a mixture of sand, Portland cement and IOP, which contains some finishing agents. This powder is dispersed or broadcast on the surface of the wet soft concrete, and is erased to produce a 1/8 inch thick coloring layer than the concrete below. This more dense surface is more durable than plain or integral coloured concrete. The color hardener and the overall color can be used together with pure color abrasion resistance. Color hardened agents have shortcomings: for workers, this is a dusty job that creates a very thin layer of color that can be damaged and can be exposed to the ordinary concrete below. However, the advantage is that the cost of most color materials is low, and the cost of light color (low white cement produces the overall color) is much lower. The use of IOP is 1 pounds per 100 square feet.
For decorative concrete that is embossed to reproduce the shape and texture of stone, tile, brick, or wood, a demoulding agent must be applied to the surface in order to prevent the concrete from sticking to the stamping tool. This release agent can be coloured as contrasting color to highlight or antique effect. The application method and utilization rate are similar to those of color curing agents.
The overlay is a thin topping (1 to 15 millimeters thick) of polymer modified color cement paste applied to existing concrete. Similar to stamping concrete, these toppings can be textured in various ways to resemble other materials. Some covers can be stamped by conventional stamping tools. The dosage of IOP is slightly higher than the color sclerosing agent.
Similar to paint, pigment sealants completely change the color of concrete surface. Coloured sealants can be applied to concrete with no curing (less than 28 days old) and paint is applied on solidified concrete. The use rate of IOP is similar to that of high end coatings.
The market of ferric oxide pigment used in decorative concrete is growing rapidly. It provides a consistent and cost-effective pigment, but it is only the beginning. This market is service intensive, requiring considerable technical expertise in color and concrete. In addition, the market is highly dispersed and competitive. Many of the 144 decorating exhibitors in the concrete world are pigment suppliers.