Note: Descriptions are shown in the official language in which they were submitted.
CA 02550358 2006-06-14
DRY-CAST CONCRETE BLOCKS AND MANUFACTURING PROCESS
THEREFOR
FIELD OF THE INVENTION
The present invention relates to dry-cast concrete blocks with a natural stone
appearance and
to a process for manufacturing such concrete blocks.
BACKGROUND
Concrete blocks intended to serve as paving units (e.g., pavers, paving tiles,
etc.), wall
construction units (e.g., masonry units, retaining wall units, etc.),
ornamental blocks, steps,
and other landscaping elements are sometimes provided with a natural stone
appearance over
an exposed portion thereof. Such concrete blocks can then be assembled into
paved surfaces,
walls or other structures that have a natural and aesthetic look.
Depending on their constituent concrete, concrete blocks can be broadly
divided into dry-cast
concrete blocks and wet-cast concrete blocks. Different processes are used to
manufacture
these two types of concrete blocks and, in particular, to provide them with a
natural stone
appearance.
Wet-cast concrete blocks may have a natural stone appearance realized directly
during casting,
but relatively long production times and requirements for numerous molds
typically render
impractical their efficient mass-production. For their part, dry-cast concrete
blocks normally
have relatively short production times and require only one or a few molds,
which facilitates
their mass-production. However, these relatively short production times impose
constraints
on a degree of surface irregularity that may be imparted to dry-cast concrete
blocks during
casting, thereby preventing realization of a natural stone appearance during
casting. Dry-cast
concrete blocks are thus typically subjected after casting to a mechanical
artificial
aging/weathering process (e.g., tumbling, splitting/breaking, object
impacting, etc.) to realize
desired natural stone characteristics, which decreases production efficiency.
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There is therefore a need for dry-cast concrete blocks for which a natural
stone appearance is
obtained during casting.
SUMMARY OF THE INVENTION
As embodied and broadly described herein, the invention provides a dry-cast
concrete block.
The dry-cast concrete block comprises a surface to be exposed, at least a
portion of the surface
having a cast texture with a natural stone appearance.
In one embodiment, the cast texture may have a surface level difference of
greater than 4 mm.
In one example of implementation, the dry-cast concrete block may be a paving
unit. The
surface level difference may be greater than 6 mm, such as between 6 mm and 12
mm.
In another example of implementation, the dry-cast concrete block may be a
wall construction
unit. The surface level difference may be greater than 15 mm, such as between
15 mm and 25
mm.
In one embodiment, each of a plurality of points of the cast texture may
define a respective
texture angle between 75 and 90 .
In one embodiment, the cast texture may comprise at least one valley each
having a respective
depth greater than 4 mm.
In one embodiment, the cast texture may comprise a pattern of cast relief
elements configured
to enable a second concrete block to be supported thereon.
In one embodiment, the at least a portion of the surface may be a first
portion of the surface
and the cast texture may be a first cast texture. The surface may comprise (1)
a second portion
with a second cast texture having a natural stone appearance and (2) a third
portion without
a cast texture having a natural stone appearance and that separates the first
portion and the
second portion.
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As embodied and broadly described herein, the invention also provides a
process comprising:
- providing no-slump concrete into a cavity of a mold, the cavity being
configured to
form a concrete block comprising a surface to be exposed with at least a
portion that
has a cast texture with a natural stone appearance;
- consolidating the no-slump concrete to form the concrete block in the
cavity of the
mold; and
- removing the concrete block from the cavity of the mold.
In one embodiment, the cavity of the mold has a surface with at least a
portion having a
texture defining a surface level difference of greater than 4 mm.
In one embodiment, the process may further comprise cleaning the cavity of the
mold using
a fluid. In another embodiment, the process may farther comprise cleaning the
cavity of the
mold using a fluid and a brush.
In one embodiment, the cavity of the mold is a first cavity, the concrete
block is a first
concrete block, and the cast texture is a first cast texture having a first
configuration. The mold
comprises a second cavity configured to form a second concrete block
comprising a surface
to be exposed with at least a portion that has a second cast texture with a
natural stone
appearance, the second cast texture having a second configuration different
from the first
configuration. The first cavity has a first volume and the second cavity has a
second volume
substantially corresponding to the first volume. The process may comprise
providing no-slump
concrete simultaneously into the first and second cavities of the mold.
In one embodiment, the cavity of the mold is a first cavity, the concrete
block is a first
concrete block, and the cast texture is a first cast texture having a first
configuration. The mold
comprises a second cavity configured to form a second concrete block
comprising a surface
to be exposed with at least a portion that has a second cast texture with a
natural stone
appearance, the second cast texture having a second configuration different
from the first
configuration. The first cavity has a first volume per unit area and the
second cavity has a
second volume per unit area substantially corresponding to the first volume
per unit area. The
process may comprise providing no-slump concrete simultaneously into the first
and second
cavities of the mold.
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In one embodiment, there is provided a dry-cast concrete block comprising a
surface to be exposed, at least a portion of said surface having a cast
texture with
natural stone appearance, wherein each of a plurality of points of said cast
texture
defines a respective texture angle between 750 and 900 and wherein said cast
texture comprises a plurality of peaks and valleys and at least one of said
valleys
has a depth greater than 4 mm; and wherein said cast texture includes a
pattern of
cast relief elements configured to enable a second concrete block to be
supported
thereon.
In one embodiment, there is provided a dry-cast concrete block comprising a
surface to be exposed, at least a portion of said surface having a cast
texture with a
natural stone appearance, said cast texture comprising a plurality of peaks
and
valleys, at least one of said valleys having a depth greater than 4 mm and a
side
extending along a valley plane, a texture angle of between 75 and 90 being
defined between said valley plane and an imaginary plane perpendicular to a
thickness axis of said dry-cast concrete block; and wherein said cast texture
inclues
a pattern of cast relief elements configured to enable a second concrete block
to be
supported thereon.
In one embodiment, there is provided a dry-cast concrete block comprising a
surface to be exposed, at least a portion of said surface having a cast
texture with a
natural stone appearance, said cast texture comprising a plurality of peaks
and
valleys wherein at least one of said valleys has a depth greater than 4 mm and
wherein at least one of said valleys has a side extending along a valley
plane, a
texture angle of between 75 and 90 being defined between said valley plane
and
an imaginary plane perpendicular to a thickness axis of said dry-cast concrete
block; and wherein said cast texture includes a pattern of cast relief
elements
configured to enable a second concrete block to be supported thereon.
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In one embodiment, there is provided a dry-cast concrete block made by a dry-
casting process, said dry-cast concrete block comprising a surface to be
exposed,
at least a portion of said surface having a cast texture with a natural stone
appearance, said cast texture comprising a pattern of cast relief elements
formed
during the dry-casting process wherein said pattern of cast relief elements
defines a
plurality of peaks and valleys, at least one of said valleys having a depth
greater
than 4 mm and a side extending along a valley plane, a texture angle of
between
75 and 900 being defined between said valley plane and an imaginary plane
perpendicular to a thickness axis of said dry-cast concrete block; and wherein
said
cast texture includes a pattern of cast relief elements configured to enable a
second
concrete block to be supported thereon.
In one embodiment, there is provided a process comprising:
- providing no-slump concrete into a cavity of a mold, the cavity being
configured to form a concrete block comprising a surface to be exposed with
at least a portion that has a cast texture with a natural stone appearance,
wherein said cast texture comprises a plurality of peaks and valleys and at
least one of said valleys has a depth greater than 4 mm; wherein said cast
texture includes a pattern of cast relief elements configured to enable a
second concrete block to be supported thereon;
- consolidating the no-slump concrete to form the concrete block in the
cavity
of the mold; and
- removing the concrete block from the cavity of the mold.
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These and other aspects and features of the invention will now become apparent
to those of
ordinary skill in the art upon review of the following description of
embodiments of the
invention in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
A detailed description of embodiments of the invention is provided below, by
way of example
only, with reference to the accompanying drawings, in which:
Figure 1 shows a paved surface comprising a plurality of concrete blocks in
accordance with
a first embodiment of the invention;
Figure 2 shows a perspective view of a given concrete block of the concrete
blocks shown in
Figure 1;
Figure 3 shows a cross-sectional view of the concrete block of Figure 2,
illustrating a cast
texture of a surface portion of the concrete block that has a natural stone
appearance;
Figure 4 illustrates a cross-sectional view of an embodiment where a surface
portion of a
concrete block that has a natural stone appearance is contiguous to a
chamfered, rounded or
otherwise non-natural looking edge portion of the concrete block;
Figure 5 illustrates a cross-sectional view of an embodiment in which a
minimum level of a
surface portion of a concrete block that has a natural stone appearance is not
located at a
boundary of that surface portion; and
Figures 6A to 6D show various embodiments of concrete blocks each having a
surface portion
that comprises a different pattern of cast relief elements;
Figure 7 shows a wall portion comprising a plurality of concrete blocks in
accordance with a
second embodiment of the invention;
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Figure 8 shows a perspective view of a given concrete block of the concrete
blocks shown in
Figure 7;
Figures 9A and 9B show embodiments in which a concrete block comprises a
plurality of
surface portions with a cast texture that has a natural stone appearance; and
Figure 10 is a flowchart illustrating an example of implementation of a
process for
manufacturing concrete blocks in accordance with embodiments of the invention.
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.
DETAILED DESCRIPTION OF EMBODIMENTS
Figure 1 shows a paved surface 10 comprising a plurality of concrete blocks
12i...12N in
accordance with a first embodiment of the invention. In this embodiment, the
concrete blocks
121...12N are pavers. In other embodiments, the concrete blocks 121...12N may
be paving tiles
or any other type of paving units. Also, in this example of implementation,
the concrete blocks
121...12N have various shapes and sizes and are arranged in various laying
patterns. Generally,
the concrete blocks 121...12N may have any desired shape and size, and may be
arranged in
any desired laying pattern.
Referring to Figures 2 and 3, there is shown a given concrete block 12j of the
concrete blocks
121...12N (1 j The concrete block 12j is a dry-cast concrete block, i.e.,
it is made of no-
slump concrete. No-slump concrete (also known as zero-slump concrete) can be
viewed as
concrete with a slump of 6 mm or less. It will be appreciated that various
types of no-slump
concrete are possible and may be used.
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.
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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 Figures 2 and 3, the natural stone-like surface portion 16
substantially
corresponds to the entire surface 141 with its boundary 22 substantially
corresponding to edges
of the surface 141. In other embodiments, the natural stone-like surface
portion 16 may be only
a limited portion of the surface 141 (i.e., not all of that surface), and, in
some cases, may be
one of a plurality of natural stone-like surface portions of the surface 141.
Also, as shown in
Figure 4, in embodiments where the natural stone-like surface portion 16 is
contiguous to a
chamfered, rounded, or otherwise non-natural stone looking edge portion 28 of
the concrete
block 12j (e.g., an edge portion serving as a joint), the boundary 22 of the
natural stone-like
surface portion 16 is considered to be configured such that the chamfered,
rounded or
otherwise non-natural stone looking edge portion 28 is not part of the natural
stone-like
surface portion 16.
Continuing with Figures 2 and 3, the natural stone-like surface portion 16
includes a pattern
of cast relief elements 181...18m formed during casting of the concrete block
12j. This pattern
of cast relief elements 181...18m includes a plurality of bumps or peaks and a
plurality of
valleys or depressions, which are sized so as to be visually distinguishable
when the concrete
block 12i is placed in the paved surface 10. It is to be understood that
various other patterns
of cast relief elements are possible. For example, Figures 6A to 6D illustrate
various
embodiments of concrete blocks each having a natural-stone like surface
portion that includes
a different pattern of cast relief elements.
The cast texture of the natural stone-like surface portion 16 defines a
"surface level difference"
AL, which refers to the normal distance between a maximum level Lõ of that
surface portion
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and a minimum level Lmjn of that surface portion. As shown in Figure 3, the
concrete block 12j
can be viewed as defining orthogonal X, Y and Z axes, where the X-Y plane is
parallel to a
plane that would be formed by the natural stone-like surface portion 16 if
that surface portion
was flat, i.e., the plane in which lies the boundary 22 of the natural stone-
like surface portion
16. A level L at a given point of the natural stone-like surface portion 16
can be viewed as a
plane parallel to the X-Y plane, and the surface level difference AL can be
viewed as being
measured along the Z axis.
In the embodiment shown in Figures 2 and 3, the minimum level Lniin of the
natural stone-like
surface portion 16 is located at its boundary 22. Generally, the minimum level
Lmin of the
natural stone-like surface portion 16 may be located anywhere on that surface
portion. For
example, Figure 5 illustrates an embodiment in which the minimum level Lmjn of
the natural
stone-like surface portion 16 is not located at its boundary 22. The maximum
level Lma., of the
natural stone-like surface portion 16 may also be located anywhere on that
surface portion,
including at its boundary 22.
Returning to Figures 2 and 3, in this embodiment where the concrete block 12j
is for use in
a paving application, the surface level difference AL may greater than 6 mm,
for example,
between 6 mm and 12 mm. For instance, in one embodiment, the surface level
difference AL
may be about 8 mm. This enables the natural stone-like surface portion 16 to
exhibit desired
natural stone appearance characteristics, while maintaining a degree of
surface irregularity
suitable for supporting pedestrian or other traffic.
It is generally contemplated that a surface level difference AL 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 Figures 2 and 3, each of the cast relief elements
181...18m of the
natural stone-like surface portion 16 reaches a respective level L that is the
maximum level
Lmõ, the minimum level Lmth, or a level therebetween. In this embodiment, a
plurality of the
cast relief elements 181...18m are seen in Figure 3 as extending to the
maximum level L,,õ of
the natural stone-like surface portion 16 and separated from each other by
other ones of the
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cast relief elements 181 ...18m that only extend to lower levels. More
particularly, the natural
stone-like surface portion 16 is configured such that at least three of the
cast relief elements
181 ...18m extend to the maximum level Lmax and are positioned relative to
each other to
provide an effective support on which at least one other concrete block may be
supported. In
other words, the maximum level Lõ,õ of the natural stone-like surface portion
16 provides 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. This facilitates stacking
or palletizing of
concrete blocks for storage or transportation purposes.
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 Lniõ
of the surface portion 16 and that valley's deepest point. Depending on the
surface level
difference AL, 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 Figures 2 and 3, in this embodiment, the natural stone-like
surface portion
16 interacts with ambient light to create shadows that further contribute to
its natural stone
appearance. More particularly, as shown in Figure 3, each point of the cast
texture of the
natural stone-like surface portion 16 defines a respective "texture angle" 0,
which refers to the
angle between a plane parallel to the X-Y plane and a plane tangent to the
natural stone-like
surface portion 16 at that point.
In one embodiment, the respective texture angle 0 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
AL in the above-mentioned ranges has been found to facilitate, if not
altogether render
possible, formation of such texture angles 0 during casting. It is noted,
however, that the
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CA 02550358 2006-06-14
above-mentioned values of texture angle 0 are presented for example purposes
only and are
not to be considered limiting in any respect.
Turning now to Figure 7, there is shown a wall portion 60 comprising a
plurality of concrete
blocks 621 ...62R in accordance with a second embodiment of the invention. In
this
embodiment, the concrete blocks 621 ...62R are masonry units. In other
embodiments, the
concrete blocks 621...62R may be retaining wall units. Generally, the concrete
blocks
62i...62R may be any type of wall construction unit used in various types of
walls, including
building walls, retaining walls and other landscaping walls, acoustic walls,
etc. The concrete
blocks 621...62R have a certain shape and size and are arranged in a certain
laying pattern.
Generally, the concrete blocks 621 ...62R may have any desired shape and size,
and may be
arranged in any desired laying pattern.
Referring to Figure 8, there is shown a given concrete block 62j of the
concrete blocks
621...62N (1 j The concrete block 62j is a dry-cast concrete block having a
generally
rectangular prism configuration with six surfaces 641...646. The concrete
block 62j may,
however, have any desired configuration with any desired number of surfaces.
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, Figures
9A and 9B show
embodiments in which are provided a plurality of natural stone-like surface
portions 66k.. .66Q
separated by a surface portion 80 that does not have a natural stone
appearance and can serve
as a false joint (where Q = 2 in Figure 9A and Q ¨ 4 in Figures 9B).
Generally, any number
of natural stone-like surface portions may be provided. Such a plurality of
natural stone-like
surface portions 161...16Q results in a wall portion seeming to include
several blocks of
various sizes and configurations.
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Returning to Figure 8, the natural stone-like surface portion 66 includes a
pattern of cast relief
elements formed during casting of the concrete block 62i. It is to be
understood that various
other patterns of cast relief elements are possible. For example, the natural
stone-like surface
portions 661 ...66Q in Figures 9A and 9B illustrate various other examples of
possible patterns
of cast relief elements.
The cast texture of the natural stone-like surface portion 66 defines a
surface level difference
L. In this embodiment, where the concrete block 62i is for use in a wall
construction
application, the surface level difference AL may be greater than 15 mm, for
example, between
mm and 25 mm. For instance, in one embodiment, the surface level difference AL
may be
about 20 mm. The surface level difference AL 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 AL
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 Figures 9A and 9B, different ones of the natural stone-like
surface portions
66k...66Q may define a common or distinct surface level difference AL and may
have common
or distinct maximum levels Lniõ and minimum levels Lmth.
With continued reference to Figure 8, each of the cast relief elements of the
natural stone-like
surface portion 66 extends to a respective level L that is the maximum level
Lmax, the
minimum level Lmin, or a level therebetween. In this embodiment, a plurality
of the cast relief
elements extend to the maximum level Lmax of the natural stone-like surface
portion 66 and
are separated from each other by other ones of the cast relief elements that
only extend to
lower levels. More particularly, the natural stone-like surface portion 66 is
configured such
that at least three of the cast relief elements extend to the maximum level
Lmax and are
positioned relative to each other to provide an effective support on which at
least one other
concrete block may be supported. In other words, the maximum level 1õõ,, of
the natural stone-
CA 02550358 2006-06-14
like surface portion 66 provides 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. In
embodiments such as those shown in Figures 9A and 9B, these at least three
points may be
distributed among the plurality of natural stone-like surface portions 661
...66g. As mentioned
previously, this facilitates stacking or palletizing of concrete blocks for
storage or
transportation purposes.
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 L. This may further enhance natural stone appearance
characteristics
exhibited by the natural stone-like surface portion 66.
Continuing with Figure 8, each of a plurality of points of the cast texture of
the natural stone-
like surface portion 66 defines a respective texture angle 0 that may be
between about 75 and
about 90 . This may contribute to creation of shadows on the natural stone-
like surface portion
66 that further enhance its natural stone appearance. It is to be noted,
however, that the above-
mentioned values of texture angle 0 are presented for example purposes only
and are not to
be considered limiting in any respect.
It will thus be appreciated that when the concrete blocks 121...12N are
positioned in the paved
surface 10 (Figure 1), each concrete block's natural stone-like surface
portion 16 contributes
to providing a natural and aesthetic look to the paved surface 10 while
maintaining surface
irregularity to a degree suitable for supporting pedestrian or other traffic.
Similarly, when the
concrete blocks 621...62R are positioned in the wall portion 60 (Figure 7),
each concrete
block's natural stone-like surface portion 66 contributes to providing a
natural and aesthetic
look to the wall portion 60. Furthermore, the natural stone appearance of each
of the concrete
blocks 121...12N and 621...62R is realized during casting of these concrete
blocks, without
requiring any subsequent mechanical artificial aging/weathering process (e.g.,
tumbling,
splitting/breaking, object impacting, etc.). Moreover, since they are made of
no-slump
concrete, production time for the concrete blocks 121...12N and 621 ...62R may
be significantly
less than that required for wet-cast concrete blocks. Concrete blocks such as
the concrete
blocks 121...12N and 621 ...62R may therefore be mass-produced with high
efficiency.
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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 Figure 10, there is shown a flowchart illustrating an example of
implementation
of a process for manufacturing concrete blocks such as the above-described
concrete blocks
121...12N and 621...62R.
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 AL ' that corresponds to the
desired surface level
difference AL (Figure 3) of the concrete block to be formed. Each point of
this surface portion
also defines a respective texture angle 0' corresponding to the desired
texture angle 0 (Figure
4) of each point of the concrete block to be formed.
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
Figures 9A and 9B),
each cavity of the mold that is intended to form such concrete blocks defines
a corresponding
plurality of natural stone-like surface portions.
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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 AL ' and
texture angles 9' 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.
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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).
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CA 02550358 2006-06-14
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 Figure 10, in this example, the process returns to step 200 where
a new
production cycle begins. In some embodiments, utilization of no-slump concrete
in
combination with rapid cleaning of the mold and other elements of the process
may enable a
production cycle to take a relatively short period of time (e.g., 15 to 20
seconds in some cases).
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.
