A detailed description of embodiments of the invention is provided below, by way of example only, with reference to the accompanying drawings, in which:
It is to be expressly understood that the description and drawings are only for the purpose of illustrating certain embodiments of the invention and are an aid for understanding. They are not intended to be a definition of the limits of the invention.
Referring to
The concrete block 12j can be said to have a generally rectangular prism configuration with six surfaces 141 . . . 146. The concrete block 12j may have, however, any desired configuration with any desired number of surfaces.
The surface 141 is intended to be exposed when the concrete block 12j is placed in the paved surface 10. At least a portion 16 of the surface 141 has a cast texture having a natural stone appearance, i.e., an aged, worn, or weathered appearance that resembles natural stone. As described later on, the cast texture of the portion 16 of the surface 141 is realized during casting of the concrete block 12j and may be based on a natural stone's surface which has been used to produce a mold for casting the concrete block 12j. For ease of reference, the portion 16 of the surface 141 and its cast texture with a natural stone appearance will hereinafter be referred to as the “natural stone-like surface portion” 16.
The natural stone-like surface portion 16 has a visually discernible boundary 22. In the embodiment of
Continuing with
The cast texture of the natural stone-like surface portion 16 defines a “surface level difference” ΔL, which refers to the normal distance between a maximum level Lmax of that surface portion and a minimum level Lmin of that surface portion. As shown in
In the embodiment shown in
Returning to
It is generally contemplated that a surface level difference ΔL of greater than 4 mm achieves satisfactory results in terms of natural stone appearance of a surface portion of a concrete block since it enables presence of visually distinguishable cast texture features mimicking surface texture of natural stone.
With continued reference to
Also, in this embodiment, each of the cast relief 181 . . . 18M of the natural stone-like surface portion 16 that is a valley (e.g., the cast relief element 182) can be viewed as having a respective “depth” D, which refers to the normal distance between the maximum level Lmax of the surface portion 16 and that valley's deepest point. Depending on the surface level difference ΔL, in some embodiments, the respective depth D of each of one or more valleys of the natural stone-like surface portion 16 may be greater than 4 mm, for example, between 4 mm and 10 mm. This may further enhance natural stone appearance characteristics exhibited by the natural stone-like surface portion 16, while maintaining a degree of surface irregularity suitable for supporting pedestrian or other traffic.
Continuing with
In one embodiment, the respective texture angle θ of each of a plurality of points of the natural stone-like surface portion 16 may be between about 75° and about 90°. This may contribute to creation of shadows on the natural stone-like surface portion 16 that further enhance its natural stone appearance. Configuring a dry-cast concrete block with a surface level difference ΔL in the above-mentioned ranges has been found to facilitate, if not altogether render possible, formation of such texture angles θ during casting. It is noted, however, that the above-mentioned values of texture angle θ are presented for example purposes only and are not to be considered limiting in any respect.
Turning now to
Referring to
The surface 641 is intended to be exposed when the concrete block 62j is positioned in the wall portion 60. The surface 641 has a natural stone-like surface portion 66 with a cast texture having a natural stone appearance. The natural stone-like surface portion 66 has a visually discernible boundary 72. In this embodiment, the natural stone-like surface portion 66 substantially corresponds to the entire surface 641 with its boundary 72 substantially corresponding to edges of the surface 641. In other embodiments, the natural stone-like surface portion 66 may be only a limited portion of the surface 641 (i.e., not all of that surface). In yet other embodiments, the natural stone-like surface portion 66 may be one of a plurality of natural stone-like surface portions of the surface 641. For example,
Returning to
The cast texture of the natural stone-like surface portion 66 defines a surface level difference ΔL. In this embodiment, where the concrete block 62j is for use in a wall construction application, the surface level difference ΔL may be greater than 15 mm, for example, between 15 mm and 25 mm. For instance, in one embodiment, the surface level difference ΔL may be about 20 mm. The surface level difference ΔL can be generally greater for a wall construction application than for a paving application, since there is no requirement to maintain a degree of surface irregularity suitable for supporting pedestrian or other traffic.
As mentioned previously, for various applications including the above-described paving and wall construction applications, it is generally contemplated that a surface level difference ΔL of greater than 4 mm achieves satisfactory results in terms of natural stone appearance of a surface portion of a concrete block since it enables presence of visually distinguishable cast texture features mimicking surface texture of natural stone. Also, in embodiments such as those shown in
With continued reference to
Also, while not shown in this example, in other embodiments, the cast relief elements of the natural stone-like surface portion 66 may include one or more valleys each having a respective depth D that may be greater than 4 mm (e.g., between 4 mm and 10 mm), depending on the surface level difference ΔL. This may further enhance natural stone appearance characteristics exhibited by the natural stone-like surface portion 66.
Continuing with
It will thus be appreciated that when the concrete blocks 121 . . . 12N are positioned in the paved surface 10 (
Although the above-described embodiments relate to concrete blocks for use in paving and wall construction applications, this is not to be considered limiting in any respect as concrete blocks in accordance with other embodiments of the invention may be used in various other types of applications, including steps construction, curb construction, and other landscaping applications.
Referring to
At step 200, no-slump concrete is placed into a mold. To facilitate mass-production, in one embodiment, the mold has a plurality of cavities. In other embodiments, a plurality of molds each with a single cavity or each with a respective plurality of cavities may be used. To further facilitate mass-production, the mold may be located such that concrete blocks are placed on a production board when removed therefrom.
Each cavity of the mold is configured to form a respective concrete block comprising a surface that includes a natural stone-like surface portion (e.g., the concrete block 12j with its natural stone-like surface portion 16 or the concrete block 62j with its natural stone-like surface portion 66). To that end, each cavity is defined in part by a surface of the mold that includes a portion with a surface texture corresponding to the desired natural stone appearance (hereinafter referred to as “the natural stone-like surface portion of the mold”). This surface portion thus defines a surface level difference ΔL′ that corresponds to the desired surface level difference ΔL (
It will be appreciated that, in embodiments directed to producing concrete blocks with a plurality of natural stone-like surface portions (such as those shown in
In order to closely simulate natural stone, in one embodiment, each given natural stone-like surface portion of the mold, and thus the corresponding natural stone-like surface portion of concrete blocks to be formed by the mold, is based on a natural stone's surface. In one example of implementation, data representative of at least a portion of the natural stone's surface is obtained, for instance, via three-dimensional scanning of the natural stone's surface. The obtained data may then be computer processed using software in order to generate data representative of the given natural stone-like surface portion of the mold. In some cases, this processing may include modifying the obtained data representative of at least a portion of the natural stone's surface to set the desired surface level difference ΔL′ and texture angles θ′ of the given natural stone-like surface portion. This processing may also ensure that the data representative of the given natural stone-like surface portion of the mold will result in the corresponding natural stone-like surface portion of concrete blocks to be formed by the mold having at least three points that are located relative to each other such that at least one other concrete block may be supported thereon in a stable manner.
As another possible consideration, in embodiments where individual ones of the cavities of the mold are intended to form concrete blocks of similar overall dimensions (i.e., length, width and height) but with natural stone-like surface portions that have different configurations (e.g., different patterns of cast relief elements), these individual cavities may be designed to each have a common volume in order to facilitate production. In other words, a first cavity intended to form concrete blocks with natural stone-like surface portions having a first configuration may have a first volume, and a second cavity intended to form concrete blocks with natural stone-like surface portions having a second configuration different from the first configuration may have a second volume substantially corresponding to the first volume. This facilitates provision of substantially the same quantity of concrete into each cavity of the mold, which in turn facilitates efficient casting of concrete blocks in the mold and subsequent removal of the concrete blocks therefrom.
In embodiments where individual ones of the cavities of the mold are intended to form concrete blocks of significantly different overall dimensions (i.e., length, width and height) and with natural stone-like surface portions that have different configurations (e.g., different patterns of cast relief elements), similar production benefits may be achieved by designing these individual cavities to each have a common volume per unit area.
The mold may be manufactured via computer-aided manufacturing based on the data representative of each given natural stone-like surface portion of the mold. With no-slump concrete being used, the mold may be made of metal or other rigid material. There is no requirement for one or more portions of the mold to be made of elastomeric material (e.g., rubber), which is typically used in molds for casting wet-cast concrete blocks with a natural stone appearance.
Thus, during step 200, each cavity of the mold is filled with no-slump concrete in order to form a concrete block with at least one natural stone-like surface portion.
At step 202, the no-slump concrete in the mold is consolidated. Consolidation may include inducing vibration of the no-slump concrete in the mold so as to cause it to compact itself and closely conform to each cavity of the mold. A pre-vibration phase may be effected during step 200 to facilitate filling of the no-slump concrete in the mold and its eventual consolidation. Consolidation may also include application of pressure on the concrete in combination with its vibration. It will be appreciated that consolidation may be effected using various other techniques.
Upon completion of step 202, the no-slump concrete in each cavity of the mold has formed into a concrete block with at least one natural stone-like surface portion.
At step 204, the concrete block in each cavity of the mold is removed therefrom and continues on the production board. The concrete blocks may be directly stored for curing purposes. Since provision of a natural stone appearance is effected during casting, the concrete blocks do not require a subsequent mechanical artificial aging/weathering process (e.g., tumbling, splitting/breaking, object impacting, etc.) to impart them with such an appearance. Also, the concrete blocks may directly be stacked or palletized in a stable manner since the at least one natural stone-like surface portion of each concrete block has been configured to provide at least three points that are located relative to each other to ensure such stable supporting. With the concrete blocks being made of no-slump concrete, curing times are relatively short such that they are available for use within a short period of time (e.g., one day).
At step 206, each cavity of the mold is cleaned such that casting of new concrete blocks may be effected. In one embodiment, a cleaning unit uses a fluid to clean each cavity of the mold. The fluid may be a gas (e.g., compressed air) or a liquid whose flow relative to each cavity of the mold, and particularly each natural stone-like area of the mold, removes therefrom substantially any remaining no-slump concrete. Such a fluid-based cleaning action advantageously enables rapid cleaning of each cavity of the mold, thereby increasing production efficiency. In some cases, the cleaning unit may also use, in addition to the fluid, one or more brushes to clean each cavity of the mold, whereby the fluid-based cleaning action is combined with a brushing cleaning action. It will be appreciated that other embodiments may employ various other types of cleaning action.
As shown in
Although various embodiments and examples have been presented, this was for the purpose of describing, but not limiting, the invention. Various modifications and enhancements will become apparent to those of ordinary skill in the art and are within the scope of the present invention, which is defined by the attached claims.