We offer a generic concrete recipe:
- 4 parts gravel
- 2 parts sand
- 1 part Portland cement and water
- Mix ingredients, pour into forms, and allow to set.
Various forms of concrete have been used since the times of the Assyrians, Babylonians, Egyptians, and Romans. Concrete is one of the strongest, and most widespread, building materials. Its manufacture and use offer opportunities to apply clean technology from multiple patentECO indexes such as Air, Energy, Industry, Extraction & Harvesting, and Water.
Inventors James Glessner (Santa Rosa, CA), Richard McCabe (Occidental, CA), and Meredith Ware (East Palo Alto, CA) offer a glimpse of how concrete can be more efficiently made. Their invention, patent number 7,727,327, is a “Low embodied energy concrete mixture.” Awarded on June 1, 2010, the patent is classified as 106/644 which includes inventions dealing with fiber, bar or wire containing compositions within the coating or plastic compositions technologies. Why would cleantech concrete be found here?
It all depends on how the technology class, in this case Class 106 Compositions: Coating or Plastic, is defined by the USPTO. Their definition states:
“This class is the broad generic class for:
(1) Coating, impregnating or plastic compositions, especially those which set or harden to retain a given shape. Most of the compositions herein found are those which are capable of undergoing a change from a fluent to a nonfluent condition, or from a solid noncoherent form to a solid coherent form, which changes may be effected in any or more of the following ways:
- By setting, e.g., concrete . . .”
Glessner et al. claim:
“1. A cementitious mixture comprising: Portland cement; fly ash; silica fume; recycled aggregate; ground recycled carpet fibers; organic fibers; and water.”
This claim gets us into clean technology via “recycled aggregate; ground recycled carpet fibers; organic fibers . . .”
They further claim (claim number in parentheses) that
- the ground recycled carpet fibers comprise nanoparticles (2)
- the recycled aggregate comprises crushed, recycled concrete (3), recycled glass (4), crushed concrete and bricks (5)
- the organic fibers are rice hulls and other natural waste fibers (7)
- ground granulated blast furnace slag (8), lime kiln dust (12), or cement kiln dust (16) is substituted for some of the Portland cement
- a high range water reducer (20) is added to the mixture.
The inventors’ intention is to reduce the amount of energy needed to manufacture concrete by substituting recycled materials for Portland cement, which requires large amounts of energy to make. The use of recycled materials substituted for aggregate reduces the amount of virgin aggregate that would otherwise need to be mined. Assuming that the strength characteristics of the concrete made according to the invention are satisfactory for the intended use, this appears to be a multiple win-win clean technology innovation.