[0001] The present invention relates, in general, to a multi-purpose prefabricated slab,
called "Eisekofly-Dalle-Beton-Papier". More specifically, it is a prefabricated reinforced
concrete (R.C.) or prestressed reinforced concrete (P.C.) slab with special features
that allow it to be used in an easy and advantageous manner compared to known precast
slabs.
[0002] As is well known, prefabricated two-dimensional structures, known as precast slabs,
are usually used to quickly construct slabs.
[0003] The best known prefabricated slab is the hollow core slab. It is a self-supporting
structure, made of concrete with pre-stressed reinforcement made of strands, without
shear reinforcement or distribution nets.
[0004] The honeycomb slab usually has a width of 120 cm or less and a height between 12
and 70 cm.
[0005] Holes are cut into the inside of the honeycomb slab to make the structure lighter.
[0006] The honeycomb slab is usually manufactured using an automatic extrusion machine that
also creates the lightening holes, the number of which varies depending on the manufacturer
and the application requirements.
[0007] The most significant problem with the honeycomb slab is precisely the need to use
special machines to make it, which increases its cost and, above all, makes it inflexible
in terms of size and shape.
[0008] Another well-known prefabricated slab type is the 'Predalle' slab, which has a width
of 250 cm or less and a height of between 15 and 70 cm.
[0009] The 'Predalle' slab is self-supporting and is made of pre-stressed concrete and prestressed
reinforcement.
[0010] The 'Predalle' slab has reinforcement made of strands and/or slow reinforcement,
nets and stirrups. Lightening is achieved by means of polystyrene shapes.
[0011] The production of the "Predalle" slab takes place in successive steps on a flat bench,
working in layers. As a result, it is not possible to cut holes as in the case of
the honeycomb slab, but by means of polystyrene shapes that can have various conformations,
although the typical one is rectangular in cross-section.
[0012] The biggest problem with the "Predalle" slab is precisely the presence of the polystyrene
shapes, which are polluting and not eco-friendly.
[0013] In particular, the 'Predalle' slab cannot be used in all those countries where the
use of non-eco-compatible materials is prohibited.
[0014] For example, in France it is forbidden to use slab whose lightening is realised through
the use of materials derived from petroleum.
[0015] The purpose of the present invention is to offer a prefabricated slab that is lightened
without the aid of polluting lighteners.
[0016] Another purpose of the invention is to provide a prefabricated slab that is easily
fabricated.
[0017] A further purpose of the invention is to provide a prefabricated slab whose mode
of construction allows it to be manufactured flexibly, varying in size, shape and
characteristics according to the requirements of use.
[0018] These and other purposes are achieved, according to the invention, by a prefabricated
slab comprising a concrete structure and reinforcement.
[0019] In particular, the prefabricated slab according to the invention is characterised
by comprising within it at least one lightening element made of a material typically
chosen from paper or cardboard or both, said element being capable of creating a volume
of lower density than the concrete portion within the prefabricated slab.
[0020] In this way, the lightening of the slab according to the invention is achieved without
the aid of polystyrene moulds or other petroleum-derived and therefore environmentally
unfriendly material.
[0021] Advantageously, the one or more lightening elements can be internally filled, so
as to avoid any bending or folding.
[0022] Alternatively, the one or more lightening elements may be internally hollow, so as
to further decrease the weight of the slab of the invention.
[0023] Advantageously, one or more lightening elements may have a parallelepiped shape and/or
a cylindrical shape depending on the overall volume and dimensions of the prefabricated
slab to be lightened.
[0024] This reinforcement usually comprises at least one strand or mesh or both.
[0025] Furthermore, in order to realise a reinforced structure, the prefabricated slab may
comprise at least one strand and/or at least one mesh and/or one U-element.
[0026] In particular, the U-shaped element may protrude from the structure, so as to be
a useful coupling element for an eventual casting above the prefabricated slab itself.
[0027] Advantageously, the prefabricated slab may comprise at least one fastening element
useful for lifting the prefabricated slab when it is to be placed in the desired position.
[0028] Further features and details can be better understood from the following description,
which is given as a non-limiting example, as well as from the accompanying drawing
tables in which
figure 1 is a top view of a prefabricated slab according to the invention;
figure 2 is a side view of the prefabricated slab of figure 1;
figure 3 is a sectional side view of the prefabricated slab according to the sectional
plane indicated by A-A in figure 1;
figure 4 is a cross-sectional side view of the prefabricated slab according to the
cross-sectional plan indicated with B-B in figure 1
Figure 5 is a top view of a prefabricated slab according to a variant of the invention;
figure 6 is a side view of the prefabricated slab of figure 5;
figure 7 is a sectional side view of the prefabricated slab according to the sectional
plane indicated with A-A in figure 5;
Figure 8 is a cross-sectional side view of the prefabricated slab according to the
cross-sectional plan indicated with B-B in figure 5.
[0029] With reference to the appended figures, in particular figures 1 to 4, a prefabricated
slab according to the invention is referred to as 10 in its entirety.
[0030] The precast slab 10 comprises a concrete structure 12 in the shape of a parallelepiped
in which strands are embedded.
[0031] A lower mesh 16 and an upper mesh 18, both made of a metal alloy, are also embedded
in the concrete structure 12 so as to make, together with the strands 14, a reinforcement
embedded in the concrete structure 12.
[0032] Three parallelepiped lightening elements 20 are included in the concrete structure
12 to lighten the precast slab 10.
[0033] In particular, such parallelepiped elements 20 (of which only one is indicated with
reference 20) are made entirely of cardboard; in other words, the volume defined by
such parallelepiped elements is entirely occupied by cardboard.
[0034] Alternatively, such parallelepiped elements 20 may be internally hollow, i.e. made
with only the perimeter faces of cardboard.
[0035] Furthermore, as illustrated in Figure 4, the prefabricated slab 10 according to the
invention also comprises first U-shaped elements 22, which are entirely embedded in
the concrete structure 12, and second U-shaped elements 24, which protrude superiorly
from the same structure 12.
[0036] Such second U-shaped elements 24 serve to allow for a better coupling with the possible
casting arranged above the precast slab 10.
[0037] At the four corners of the structure 12 are arranged fastening elements 26 useful
for lifting the prefabricated slab 10 when it is to be arranged in the desired position.
[0038] According to a second variant of the invention illustrated in Figures 5 to 8, a prefabricated
slab 110 comprises a parallelepiped-shaped concrete structure 112 in which strands
are embedded.
[0039] A lower mesh 116 and an upper mesh 118, both of metal alloy, are also embedded in
the concrete structure 112, so as to create, together with the strands, a reinforcement
embedded in the concrete structure 112.
[0040] Included in the concrete structure 112 are six cylindrical lightening elements 120,
suitable for lightening the precast slab 110.
[0041] In particular, such cylindrical elements 120 (of which only one is indicated by reference
120) are made entirely of cardboard; in other words, the volume defined by such parallelepiped
elements is entirely occupied by cardboard.
[0042] Alternatively, such cylindrical elements 120 may be internally hollow, i.e. made
with only the perimeter faces of cardboard.
[0043] Furthermore, as illustrated in Figure 8, the prefabricated slab 110 according to
the invention also comprises first U-shaped elements 122, entirely embedded in the
concrete structure 112, and second U-shaped elements 124, which protrude superiorly
from the same structure 112.
[0044] Such second U-shaped elements 124 serve to allow for a better coupling with the possible
casting disposed above the precast slab 110.
[0045] Fixing elements 126 are arranged at the four corners of the structure 112, which
are useful for lifting the prefabricated slab 110 when it is to be arranged in the
desired position.
[0046] Further variants may also be provided which are to be considered within the scope
of the invention.
[0047] For example, the shape of the lightening elements may be other than parallelepiped
or cylindrical.
[0048] In any case, the presence of lightening elements such as parallelepiped elements
20 or cylindrical elements 120 makes it possible to avoid the use of shapes of polystyrene
or other petroleum-derived material, while still achieving the desired lightening.
[0049] Furthermore, the use of such lightening elements allows the prefabricated slab according
to the invention to be made without the use of specific machinery. Thus, it is possible
to make the prefabricated slab according to the desired shape, size and characteristics,
without constraints due to the use of machinery.
[0050] Additionally, the lightening element realised can comprise a containing structure
made of paper and/or cardboard inside which is arranged a honeycomb or lattice structure,
also typically made of paper and/or cardboard or another nonpolluting material, with
the purpose of lightening the slab, but at the same time giving solidity to the lightening
element itself.
[0051] Alternatively, the honeycomb or lattice structure can be filled with lightening material
with a lower density than concrete.
1. Prefabricated slab (10; 110) comprising a structure (12; 112) made of concrete and
a reinforcement (14, 16, 18, 22, 24; 114, 116, 118, 122, 124), characterized in that it includes within it at least one lightening element (20; 120) made of paper and/or
cardboard suitable for creating a volume of lower density than the structure (12;
112) made of concrete, within the prefabricated slab.
2. Prefabricated slab (10; 110) according to the preceding claim, wherein the at least
one lightening element (20; 120) is internally filled.
3. Prefabricated slab (10; 110) according to claim 1, wherein the at least one lightening
element (20; 120) is internally hollow.
4. Prefabricated slab (10) according to any one of the preceding claims, wherein a paper
and/or cardboard containing structure is comprised, inside which a honeycomb or mesh
structure, also made of paper and/or cardboard or other material, is arranged.
5. Prefabricated slab (110) according to any one of claims 1 to 3, wherein a paper and/or
cardboard containing structure, filled with a lightening material with a lower density
than concrete, is comprised.
6. Prefabricated slab (110) according to one of the preceding claims, wherein the at
least one lightening element (20) has a parallelepiped shape.
7. Prefabricated slab (110) according to any one of claims 1 to 5, wherein the at least
one lightening element (20) has a cylindrical shape.
8. Prefabricated floor slab (10; 110) according to any one of the preceding claims, wherein
the reinforcement comprises at least one strand (14; 114) or at least a wire mesh
(16, 18; 116, 118) or both.
9. Prefabricated slab (10; 110) according to any one of the preceding claims, wherein
at least one U-shaped member is included (22, 24; 122, 124).
10. Prefabricated slab (10; 110) according to any one of the preceding claims, wherein
the at least one U-shaped element (24; 124) protrudes from the structure (12; 112).
11. Prefabricated slab (10; 110) according to one of the preceding claims, wherein the
at least one fastener (26; 126) useful for lifting the prefabricated floor (10; 110)
when it is to be arranged in the desired position is included.