Liquid color and computer technology have revolutionized the use of integral color in concrete for contractors, designers, and homeowners. Traditionally, integral color has been available from color manufacturers only in powder form. Then it was measured and placed by truck drivers into the ready-mix truck. Batch color could vary with the amount of color introduced, the cement content in the mix, or the water in the truck.
With computer-dispensed color accuracy can be gained across doses, a large array of colors now is available, and a streamlined process helps ready-mix producers and supply houses offer a quality product.
The Color-Mixing Process
At the ready-mix plant, an operator is in charge of batching the concrete and introducing the color into the mixer in the back of the truck. The computer can tell the operator if too much or too little color was discharged so manual adjustments can be made. This system translates into savings for the contractor who gets more accurate mixes and the producer who no longer has to warehouse dry color. And both are no longer faced with replacement costs.
“The new system dispenses more evenly and minimizes or eliminates color ribboning caused by color bags that disintegrate in fresh concrete,” says Mike Lowe Jr., marketing director, Increte Systems, Odessa, Fla.
A contractor can choose to purchase color in 5-gallon containers from a construction supply house. To batch the concrete, the contractor inputs the mix design information into the manufacturer's software. The computer meters the color amount needed into 5-gallon buckets—similar to a paint store. “Smaller ready-mix producers, that may not want to invest in a large dispensing system, can choose a hybrid that uses the bucket dispensing system placing color in pails to dose trucks,” says Lowe.
In either case, the concrete contractor needs to provide the cubic yards required for the job, the cementitious content in each yard of concrete, and the specified color to calculate the pounds of component color needed.
Communicate The Details
There are a few areas of caution to keep in mind when dealing with concrete color batching. “Admixtures make a difference to color and workability,” says Roger Beckett, national accounts sales director, Davis Colors, Los Angeles. “Switching admixtures during the job could lead to a water-cement ratio change and visibly change the color. Even the same color may appear different in both horizontal and vertical applications. The slab's orientation reflects light differently and reads as different color.”
Accuracy is important. “Tell the ready-mix producer when a mix is to receive color so when the mix calls for six bags of cement per yard of concrete, there are not 6.4 bags introduced,” says Tim Marchbanks, engineering director, L.M. Scofield Co., Atlanta. “Varying the cement content affects color accuracy load to load. Concrete changes with time. Using the same color to add work to an older installation may not produce an accurate color match.”
To view shades in different finishes, Beckett suggests using a software program, such as The Concrete Palette by Davis Colors, “The program also provides the formula so a ready-mix producer with the liquid batching system can quickly create the desired color,” says Beckett.
To ensure accurate mixing, make sure to provide the manufacturer with project and mix design details. “Be specific regarding the manufacturer, [including] the color name and its number, as many color recipes have similar names,” says Marchbanks. With computer-dispensed integral color, designers now have hundreds of choices at their fingertips and the contractor can be sure the color placed into the truck is correct.
— Jeanne Fields is a freelance writer and owner of Fields Marketing, Douglas City, Calif., that provides services to the decorative concrete industry.