Process and equipment for producing concrete products having blended colors

#The invention relates generally to the production of concrete products. More specifically, the invention relates to a production process in which one or more liquid pigments are blended into concrete so that the final product is not a uniform color, but has a variegated appearance that might be described as swirled, folded, or mottled. Most specifically, the invention relates to the production of such concrete products in a dry cast process. Concrete products to which the invention can be applied include, but are not limited to, architectural concrete blocks, concrete bricks, and concrete blocks that are suitable for use in landscaping applications, such as retaining wall blocks, pavers, and slabs.

#Concrete products can be produced without any coloring agents, in which case the resulting product will have a color dictated by the native colors of the raw materials, typically cement and aggregate, that have been used. The result is typically a shade of gray. It is possible to alter this gray color by introducing a coloring agent into the mixture. The coloring agent is typically a pigment, or a mixture of pigments, that will impart the desired color to the finished product.

#There are a variety of known processes for making concrete products. In a wet cast system, a concrete mixture that contains sufficient water so that it flows readily is introduced into a closed mold. The mixture is allowed to harden in the mold, and the molded product is then stripped from the mold. In a dry cast system, a much drier concrete mixture is introduced into a mold. The concrete mixture is densified in the mold, and then removed from the mold before it has hardened. Because the concrete mixture is of a “low slump” or “no slump” nature, the molded product, if carefully handled, will retain its molded shape while it is transported to a curing area, where it will cure over a period of hours. This dry cast process is suitable for highly automated, mass production of a number of types of concrete products, including architectural concrete blocks, segmental retaining wall units, concrete bricks, slabs, and interlocking concrete pavers.

#The patent or application file contains at least one drawing or photograph executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the United States Patent and Trademark Office upon request and payment of the necessary fee.

#FIG. 1 is a schematic depiction of a known dry cast concrete product production system.

#FIG. 2 is a schematic depiction of a dry cast concrete product production system according to the present invention.

#Overview

#The present invention provides a process for producing multi-color blended concrete products, as well as to a system and equipment utilized in implementing the process. As used in this specification, the term “concrete products” includes architectural concrete blocks that are assembled with mortar to build external walls, concrete bricks, modular concrete products that are suitable for use in landscaping applications, such as retaining wall blocks, concrete pavers, concrete slabs, and other concrete products.

#The preferred application of the process, system and equipment is in the dry cast production of blocks that are used in landscaping applications, particularly retaining wall blocks that are designed to be stacked on top of one another in multiple courses to form a retaining wall, without the use of mortar.