The present invention is a brick block and process and apparatus for its manufacture. This invention is particularly useful for manufacturing chimney block having a brick pattern of preferably three courses impressed on all four vertical sides as well as for manufacturing wall block which may have a brick pattern on one, two or three sides.
The brick block of this invention comprises a rectangular block of monolithic concrete colored throughout to imitate the color of brick. At least one vertical face of the rectangular block is horizontally and vertically grooved to create a pattern simulating laid brick. The grout lines contain a coloring agent (e.g. a pigmented latex) that simulates the color of a mortared joint. The brick block may be a chimney block, all four vertical sides of which have the impressed brick pattern. It may also be a wall block having two cores and having one to two sides faces with the brick pattern or if it be an end wall block having three sides of the block with the pattern.
By the term xe2x80x9cbrick blockxe2x80x9d is meant a molded monolithic concrete block colored throughout to simulate a natural brick color one vertical face of which has an impressed brick grout pattern simulating laid brick, one, two, and preferably at least three or more courses high.
The apparatus for the manufacture of the brick block comprises a mold having four vertical walls the interior of which has the dimensions of the desired brick block. One or more of the walls has means for impressing the grout pattern on the face of the brick block as it is molded. This means includes a hydraulic system that moves a grout bar outwardly into the concrete mass as it is being formed approximately xe2x85x9 inch or so and after it is formed and before the block is ejected from the mold retracts the grout bar to be flush with the mold face.
The block has a core as is usual in the manufacture of conventional wall and chimney block. The concrete mixture has zero slump so that the impressed grout pattern is retained in the block as it is ejected from the mold. The concrete mixture has an increased moisture content while maintaining zero slump to produce on the xe2x80x9cbrickxe2x80x9d face of the block, a brick-like surface. This results in the block having a higher density as compared to that of conventional wall block. The density is usually above 100 pounds per cubic foot, e.g. 103 pounds per cubic foot.
Ejection is accomplished by having a head or ram descend from the top of the mold around the core to push the block downwardly onto a platen which is then moved out from underneath the mold and set off for curing of the concrete mass.
The hydraulic mechanism that extends and retracts the grout bar has two or more hydraulic cylinders attached to the bar so that the grout bar remains square with the face of the mold.
The mold of the present invention is adapted to fit in or onto a conventional block manufacturing machine such as the xe2x80x9cBescopacxe2x80x9d manufactured by Besser, 81 Johnson Street, Alpena, Mich. 49707. Because of the hydraulic mechanism required to impress the grout pattern, the mold is oversized or larger than that used for a standard block and some slight modification has to be made to the machine to receive the frame holding the present mold, namely, the width of the rubber dam is decreased.
Once the mold is in place, manufacture is quite straightforward. A charge of concrete, pre-colored throughout, is pushed into the mold cavity around a core or cores held in place by overhead hangers. As is conventional, the concrete is caused to settle in place by vibration during which time the grout bar is extended into the cement mixture and then is retracted after vibration has ceased. Following this, a head or ram descends into the mold to push the block out of the mold onto the platen on which it is removed. The core may be vented to prevent any vacuum forming which would distort the block. After the block has been allowed to cure, the grout lines of the brick pattern are painted as with a masonry slur or a pigmented latex the color of mortar.
The cycle time per brick block is 12 to 15 seconds. During a six-hour operating period, 1100 brick block have been made using one operator.