Color Blending for Concrete Block and Pavers

The demand for concrete block and pavers with blended colors has been increasing rapidly over the last several years. People want precise, but random colors. The colors should be delivered evenly but without any sign uniformity. It sounds almost impossible to accomplish oxymoron.

 

Getting good color blending is not impossible and actually with the right equipment and a good plan of execution. There are several methods to getting an attractive blend of colors. Often to best the best finish a producer will need to make the correct moves not just with color blending equipment, but also with the mixing and batching process as well as on the block or paver machine. This doesn't necessarily mean that you need to buy the fanciest or latest thing-a-ma-jig, more that you need to know how to operate your equipment. the best tool can be worthless if it is not understood.

Color blending is done both with face mix products and with through mixed products. The idea is to mix multiple colors in the block/paver machine in a seemingly random and aesthetically pleasing way. Generally three color blends are the goal of most block and paver producers today. Colors such as browns, tans, and Grays, are often used in liberal quantities while a color such as black, or a vivid red may be used more sparingly, as they are more striking to the eye.

Mixing and Batching:

KVM Face Mix Batching System

Batching for color blending is essentially no different than it is for a standard paver plant or a block operation that is already incorporating color. You need two silos. One for white cement and the other for gray cement. You also need aggregate holding bins, this may be two or three for a through mix process or eight to twelve if you are making face mix and/or using specialty aggregates. For batching color into the mix, I recommend either a granular or powder color, as liquid is tough in such a moisture sensitive product.

The big thing is that you need to be able to feed you mixer fast, as every product will require three separate batches to be present. Planetary mixers are often used for color blending, as they are fast mixers. There are many other excellent options for mixing colors in zero slump, but the planetary is proven very well for through mix, and for many face mix applications. If perfect face mix is you goal, there are better mixers, but you will have to pay a much higher price.



Mixer Systems Color blending

A real advantage to planetary mixers when it comes to blending is the ability for the mixer to have multiple discharge doors. this way you can have a separate hopper and conveyor for the three colors. We have placed VFD (Variable Frequency Drives) on the color conveyors to control the quantity of various colors. These belts can feed onto a conveyor, into a skip hoist, or into a flying bucket. Each of these will produce very different color results
 

Block / Paver Machine:
There are many kinds of machines for the production of block and pavers. Each one works a little different. Many have systems for feeding and evenly across the mold and knowing how to control these operations on your machine is crucial. Uncontrolled spreading can lead to dulling of colors where you want them sharp. The best thing you can do is become an expert on the equipment your run with. Of course some machines are easier to work with than others. Check out KVM equipment.