Note: Descriptions are shown in the official language in which they were submitted.
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Dividable paving slabs
The invention relates to a relatively thick concrete
paving slab used to cover a ground surface. It also
relates to its manufacturing process and the associated
mold, its distribution and its laying.
The esthetics of natural stone paving is highly
attractive and sought after. The major characteristics
explaining this esthetic effect are as follows: the
various stones used are thick, have an irregular
surface and are all of different sizes. The
disadvantage of this paving is of course its cost.
Thus, many manufacturers opt for a more economical
solution, which involves producing imitation slabs
based on concrete slabs produced by molding.
A first, currently used process for manufacturing
concrete slabs allows so-called "pressed slabs" to be
produced. In this process, concrete is poured into a
mold and then pressed, which causes it to harden
structurally to a sufficient degree to allow de-molding
and immediate handling of the slab. In this process, a
mold is used only for a very short time for each slab.
The advantage is therefore to enable many slabs to be
manufactured in one day using the six to eight molds
equipping a machine. However, these molds are
expensive and difficult to change on the machine. This
process is thus quite unsuitable for producing slabs of
various sizes, which represents a limit to reproducing
the variety of natural stone sizes. Paving slab
manufacturers use this process to manufactured a
standard slab size, usually 40 x 40, 50 x 50 or 60 x 40
centimeters. They sometimes produce slabs featuring
surface geometrical shapes, whose function is solely
esthetic, to mask this uniformity.
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A second manufacturing process of the prior art
involves casting slabs then awaiting their hardening
for 24 hours before manufactureding them. The advantage
of this process results from the fact that it is
sufficient to choose molds of various sizes to obtain
readily slabs of different sizes. Its disadvantage
results from the fact that a mold is only used once a
day, which means that as many molds as the number of
slabs to be manufactured per day are required.
An alternative allowing different size slabs to be
obtained involves factory sawing 50 x 50 centimeter
slabs produced, for example, according to the pressed
. slab process, and delivering them cut to the customer.
However, this process complicates and lengthens
significantly slab manufacture. This is because the
slabs according to the invention seek to imitate
effectively natural stones and are relatively thick, at
least 35 centimeters, which does not make their cutting
easy.
Moreover, distribution of the different size slabs
obtained according to the previous processes is complex
and represents a second disadvantage. Specifically,
their placement on a pallet, called palletization,
requires a number of slabs of each size to be
prespecified per pallet to optimize the space available
on a pallet and to offer a suitable assortment with a
view to laying.
A general object of the invention involves proposing
slabs that do not have the disadvantages of the prior
art.
More specifically, a first object of the invention
involves proposing slabs allowing the installation of
paving made up of different size slabs to imitate the
esthetics of natural stone paving.
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A second object of the invention involves proposing
thick slabs with an irregular surface to imitate the
esthetics of natural stone paving.
A third object of the invention involves proposing
slabs whose manufacturing process allows high
productivity at low cost, using an automatic rotary
press.
A fourth object of the invention involves proposing
slabs whose distribution, especially palletization, is
simple.
The concept of the invention involves manufacturing
single size pressed slabs according to the most
advantageous manufacturing process of the prior art,
incorporating means for easily dividing them prior to
laying, to obtain slabs of different sizes for laying
imitating natural stone paving.
To this end, the invention is based on a slab for
covering a ground surface, which comprises at least two
sections separated by a groove defining a breaking line
allowing the slab to be divided along this breaking
line to separate the two sections.
For a, slab thickness greater than or equal to 35
millimeters, the groove can be V-shaped and between 6
and 10 millimeters deep.
The slab is thus suitable for straightforward dividing.
The slab may have a square or rectangular overall
shape, the length of whose sides is between 40 and 100
centimeters approximately, and may comprise between 2
and 4 dividable sections.
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It may comprise three sections.
It may be overall square in shape will sides
approximately 50 centimeters in length and comprise
sections whose sides are between 20 and 50 centimeters
in length. More specifically, it may be overall, square
with sides approximately 50 centimeters in length and
comprises a first approximately 50 x 30 centimeter
sized. section, a second approximately 30 x 20
centimeter sized section and a third approximately 20 x
centimeter sized section. In an alternative
embodiment, it is overall square in shape with sides
approximately 50 centimeters in length and comprises a
first approximately 50 x 20 centimeter section, a
15 second approximately 30 x 30 centimeter section and a
third approximately 30 x 20 centimeter section.
The invention also relates to the mold for
manufacturing a slab according to the invention, which
20 comprises several sections separated by a rib suitable
for forming slab fractions separated by grooves.
The invention also relates to a slab manufacturing
process comprising a molding step, a pressing step and
a subsequent demolding step using the mold according to
the invention.
The invention also relates to a method for laying slabs
that includes the step of straightforward slab
division. In this laying method, dividing can be simply
performed by striking the slab on the projecting edge
of a hard surface or by striking the slab with a club
hammer and a wide chisel. A joint comprising polymer
filler or cement mortar can be introduced between the
slab sections.
These objects, features and advantages of the present
invention will be detailed in the following description
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of one particular embodiment provided without
limitation in conjunction with the appended figures,
amongst which:
- figure 1 represents a perspective view of a
dividable slab according to an embodiment;
- figure 2 represents a sectional view along axis
II-II of the dividable slab according to one
embodiment;
- figures 3a and 3b represent processes for
dividing a dividable slab according to one
embodiment;
- figure 4 represents a possible assortment of
slabs according to one embodiment;
- figure 5 represents an example of paving
obtained using slabs according to one embodiment;
- figure 6 illustrates a mold for implementing the
manufacturing process according to the invention
for manufacturing a slab such as the one
represented in figure 1.
The solution is based on a dividable slab 1 for which
one embodiment is represented in figure 1. It is
overall 50 x 50 centimeters in size and it is composed
of a first 50 x 30 centimeter sized section 2, a second
30 x 20 centimeter sized section 3 and a third 20 x 20
centimeter sized section 4.
Such a slab is manufactured according to the pressed
slab manufacturing process of the prior art, but using
a special mold allowing the formation of several
sections 2, 3, 4, with a surface texture, separated by
deep V-shaped grooves 5 penetrating over a thickness 6
of the slab surface. In this embodiment, the slab is 40
millimeters thick and has grooves 5 approximately 7
millimeters deep. The slab features a surface layer 16
of facing concrete, for example reconstituted stone
obtained by binding fragments of crushed stone with
cement of the same color as the stone. This layer 16 is
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slightly thicker than the thickness 6 corresponding to
the depth of the grooves 5. The bottom layer 17 of the
slab 1 is made of ordinary concrete.
The purpose of the grooves 5 is to allow the slab to be
easily divided to separate the various sections 2, 3,
4, each of these sections, once divided, having a
breaking surface flat enough to be used in paving, in
other words, a surface whose unevenness does not exceed
the usual thickness of a joint between two slabs.
The dividable slab 1 is shown in cross section in
figure 2. The two sections 2 and 3 of the slab are
separated by a groove 5, which pre-defines a breaking
line 7 within the slab thickness. The depth of the
groove is designed to allow relatively easy breakage,
as detailed hereafter, whilst avoiding excessive
weakening, leading to accidental breakage during
manufacturing or transport, for example. Compared with
the existing esthetic surface contours, a deep groove,
between 6 and 10 millimeters for an approximately 40
millimeter thick slab, must be chosen to ensure this.
Moreover, a pointed shape will be chosen for the bottom
part of the groove for clearly pre-defining the
breaking line 7 so as to obtain a relatively clean
break. A V-shaped groove is most suitable. A groove
with a wide bottom, of rectangular shape, for example,
or of insufficient depth, would be unsuitable because
the probability of obtaining breaking surfaces with
protuberances larger than the acceptable width of a
joint between two slabs would be too high. Use of such
a groove for dividing in the sense of the invention
would result in a large number of unusable slabs, which
would not fulfill the objective of an economic
solution.
According to figure 3a, a few blows of the club hammer
8 with a wide chisel on the face opposite the groove
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also allows the slab to be divided along the line 7.
According to the illustration in figure 3b, the slab
can be divided by striking it cleanly, yet
effortlessly, at its breaking line, against the
projecting edge of a hard material, for example a pack
of slabs. These very straightforward dividing methods
are particularly suitable for implementation when
laying slabs on site. They require neither complex
tooling nor great force, unlike what the use of a
sawing method could represent.
Figure 4 represents an assortment of dividable slabs
according to one possible form of division. This
assortment comprises two types of dividable slabs 1 and
11 associated with a conventional, solid slab 10 of 50
x 50 centimeter size. The slab 1 corresponds to the
previously described slab and the slab 11 is made up of
the 50 x 20 centimeter sized section 12, the 30 x 30
centimeter sized section 13 and the 30 x 20 centimeter
sized section 14. All these slabs come from the
manufacturing process in the same 50 x 50 centimeter
size, allowing easy, optimal palletization. Their
distribution is therefore equivalent to that of the
single size slabs.
Figure 5 illustrates the laying of an assortment of
slabs, such as that proposed in figure 4, comprising
three slabs 10, three slabs 1 and three slabs 11 to
form a square with approximately 1.5-meter sides.
Advantageously, joints 15 filled with polymer filler, a
material with the property of hardening with water
whilst remaining soft and porous, are introduced
between these slabs. These joints offer the advantage
of sustaining well any slight deformation of the
paving, whilst remaining in position oven time despite
bad weather and other wearing factors. They also allow
the slab side faces or the breaking surfaces, which
were not clean following the breaking that' they were
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subjected to during dividing, to be effectively
concealed. In an alternative embodiment, a cement
mortar joint can be used.
The invention also relates to the process for
manufacturing the slabs according to the invention,
described hereafter with a view to obtaining a slab as
shown in figure 1.
This manufacturing process is based on a special
plastic mold 20, illustrated in figure 6, featuring
three sections 22, 23, 24, whose sizes correspond
respectively to the sections 2, 3 and 4 of the slab 1.
Each surface of the sections 22, 23, 24 has a specific
granularity obtained by fabricating the mold 20 by
molding it on three real natural stones of
corresponding size to the sections 2, 3 and 4 of the
slab 1. The mold sections 22, 23 and 24 are separated
by a proj ecting rib 25 of triangular cross section, in
the form of a point, whose dimensions correspond to
those of the groove 5 in the slab 1.
The manufacturing process is based on an automatic
rotary press comprising between six and eight molds,
each mold 20 being used according to the following
steps:
- the bottom of the mold is filled with facing
concrete to a depth slightly greater than the height of
the ribs 25;
- the remaining volume of the mold is filled with
ordinary concrete;
- the assembly is pressed;
- then the slab is immediately demolded.
The slab 1 is then formed. It must harden for
approximately 24 hours before being totally
consolidated. As the mold 20 was produced from three
real natural stones, so the surface obtained on the
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facing concrete of the slab 1 represents a true image
of these three stones and, after dividing the three
sections 2, 3, 4, the three slabs obtained are faithful
imitations of the three original stones.
The previous embodiment was described with slabs of
50 x 50 centimeter overall size, but it could be
applied to slabs of other sizes. Sizes having sides
between 40 and 100 centimeters such as, for example, 40
x 40 centimeters, 60 x 40 centimeters, 50 x 100
centimeters, 60 x 60 centimeters, are especially suited
to application of the invention because they allow
slabs to be produced with an overall size representing
a weight that allows them to be handled, particularly
with a view to dividing them, whilst offering
possibilities of dividing sections of reasonable size.
Furthermore, the previous embodiment proposed slabs
that can be divided into three sections, but the
invention also applies to any other geometry. However,
it is particularly well suited to producing between two
and four sections to maintain straightforward, easy
dividing and obtain esthetic, mutually compatible
sizes. A larger section size would risk weakening the
slab and complicating slab dividing.
Sections of 20 x 20 centimeter minimum size are
preferable.
Finally, the choice of the slab dimensions and of the
sizes of its three sections, as described in the
embodiment in figures 1 to 5, is a choice that has a
first technical effect of particularly easy dividing
and a second technical effect of offering sections
resulting from the dividing of slabs having sizes that
are particularly mutually compatible sizes for being
distributed over a ground surface in any geometry, so
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as to obtain a crazy paving effect of the natural stone
paving.
In brief, the principle of the invention applies in
particular to slabs of rectangular shape with sides
between 40 and 100 centimetersin in length, comprising
two to four sections with a side at least 20
centimeters in length.
Finally, the invention has the following advantages:
- the manufacturing of the dividable slabs is
simple and allows a multitude of sizes to be obtained,
comparable with natural stone paving arrangements;
- the slabs obtained are thick and have an
irregular surface, imitating natural stone;
- the manufacturing process is very efficient;
- the distribution and, in particular, the
palletization of the dividable slabs is simple because
the slabs are all of the same initial size;
- the laying of the dividable slabs is
straightforward.
As a comments, slab dividing is conceivable at any time
before laying, the example of dividing on site being
advantageous but not limiting.
