Note: Descriptions are shown in the official language in which they were submitted.
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COATED FOAM FORM MEMBERS FOR CONCRETE STRUCTURES
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to building construction, and
more particularly to coated and/or laminated foam form members for concrete
structures.
[0002] Concrete pre-cast wall sections and cast-in-place wall
sections are used in known building design. One of the popular systems
available
today is pre-cast concrete tilt-up wall panels. The wall section is first cast
horizontally on a firm flat surface, for example, a temporary casting slab or
the
concrete floor of the building, by the use of a perimeter defining form. The
concrete
is poured into the area defined by the forms and is then permitted to harden
or cure.
In order that the concrete panel not adhere to the concrete floor, or surface
supporting
it, a commercially available chemical coating is first applied to the surface
as a bond
breaker. After the concrete has hardened to strength a heavy capacity lifting
crane is
employed to Lift, or tilt, the wall section to a vertical position. The wall
panel is set
upon a concrete foundation or footing at which point it is temporarily
supported until
permanently incorporated into the building structure.
[0003] It is sometimes desirable, for artistic design and/or aesthetic
reasons, that relief channels are cast into the flat concrete panel. Typically
these relief
channels extend horizontally across the concrete panel, but they can also
extend
vertically. One known method of forming the relief channels in the concrete
panels is
to fasten wooden strips cut to the desired shape of the relief channel onto
the flat
pouring surface between the perimeter forms before the concrete is poured. One
problem that occurs with wooden strips is that any natural defects in the
wood, for
example, knots, are transferred to the hardened concrete. Another problem that
occurs with wooden strips is the needed repair to the concrete floor that the
wooden
strips are nailed to. Further problems with wooden strips include moisture
absorption
which can cause swelling and warping of the strips, sap excretion which can
cause
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discoloration of the concrete in contact with the wood, jagged edges and knots
in the
wood, and poor release properties of wood.
[0004] One attempt to overcome the short comings of wooden reveal
strips is to make the reveal strips from plastic materials, for example,
polyethylene
and polypropylene. However, reveal strips made from these plastic materials
are
three to five times the cost of wooden strips, and there is a problem of
availability of
plastic reveal strips in the market place.
BRIEF DESCRIPTION OF THE INVENTION
[0005] In one aspect, a form member for use in casting concrete
articles is provided. The form member includes a foam core formed from a
foamed
polymeric material, and a protective layer covering at least a portion of at
least one
outer surface of the core. The protective layer includes at least one
polymeric
material.
[0006] In another aspect a form for casting concrete panels is
provided. The form includes a plurality of outer perimeter form members
connected
together to define a casting area, and at least one foam form member. 'The
foam form
member includes a core formed from a foamed polymeric material, and a
protective
layer covering at least a portion of at least one outer surface of the core.
The
protective layer includes at least one polymeric material.
[0007] In another aspect, A method of making a form member is
provided. The form member includes a foam core comprising a foamed polymeric
material, and a protective layer covering at least a portion of at least one
outer surface
of the core. The protective layer includes at least one polymeric material.
The
method includes forming the foam core into a predetermined shape, and applying
the
protective layer to at least one outer surface of the foam core.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 is a schematic illustration of a concrete wall panel
containing cast-in relief channels.
[0009] Figure 2 is a schematic illustration of a form for constructing
the concrete wall panel shown in Figure 1.
[0010] Figure 3 is a cross sectional schematic illustration of a reveal
strip shown in Figure 2 in accordance with an embodiment of the present
invention.
[0011] Figure 4 is a cross sectional schematic illustration of a
chamfer strip shown in Figure 2 in accordance with an embodiment of the
present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Forms for constructing concrete wall panels, that include
coated foam members, are described in more detail below. The coated foam
members
are light weight, easily cut to size, and are adhesively attached to the flat
concrete
floor on which the concrete wall panel is cast. The use of an adhesive, for
example, a
pressure sensitive adhesive and/or two sided adhesive tape, eliminates the use
of
fasteners, such as, nails, screws, and wood dowels, to fasten the reveal
strips to the
concrete floor, and thus eliminates the need to repair fastener holes in the
concrete
floor when the casting of concrete wall panels is complete. The coated foam
members are described below as being used as reveal strips in the concrete
wall panel
form; however, coated foam members can be formed into any shape and used as
other
parts of the concrete form, for example, chamfer strips and form-board support
members with chamfer portions.
[0013] Referring to the drawings, Figure 1 is a schematic illustration
of a concrete wall panel 10 containing cast-in relief channels 12. Figure 2 is
a
schematic illustration of a form 14 for constructing concrete wall panel 10.
Referring
Figures 1 and 2, form 14, in an exemplary embodiment, includes outer perimeter
form
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members 18, 20, 22, and 24 arranged to form a rectangular casting area 26 for
casting
concrete wall panel 10. In other embodiments, form 14 is other than
rectangular in
shape, for example, square shape, trapezoid shape, parallelogram shape, and
triangle
shape. Outer perimeter form members 18, 20, 22, and 24 are secured to floor 28
by
any suitable method, for example, fasteners and/or adhesives. Outer form
members
18, 20, 22, and 24 can be formed from any suitable material, for example,
wood,
metal, and the like.
[0014] Chamfer strips, 30, 32, 34, and 36 are located in casting area
26 adjacent outer form members 18, 20, 22, and 24. Chamfer strips, 30, 32, 34,
and
36 are used to form smooth beveled edges in concrete wall panel 10.
[0015] To form relief channels 12 in concrete wall panel 10,
reveal/relief strips 38 are located in casting area 26 and extend between
opposing
outer form members 20 and 24. In the exemplary embodiment, reveal strips 38
are
substantially parallel to outer form members 18 and 22 which define the top
and
bottom of concrete wall panel 10. In alternate embodiments, reveal strips are
substantially parallel to outer form members 20 and 24, or at a predetermined
angle to
outer form members 18 and 22.
[0016] Reveal strips 38 and chamfer strips 30, 32, 34, and 36 are
formed from a foamed polymeric material and include a protective layer on at
least
one surface of the foamed polymeric material. Particularly, and referring to
Figure 3,
each reveal strip 38 includes a core 40 formed from a foamed polymeric
material.
Reveal strip core 40 has a substantially trapezoidal cross sectional shape and
includes
a bottom wall 42, a top wall 44 and opposing side walls 46 and 48 extending
between
bottom and top walls 42 and 44. In alternate embodiments, core 40 has other
cross
sectional shapes, for example, square, rectangular, circular, semi-circular,
elliptical,
and the like. Each reveal strip 38 also includes a protective layer 50 located
on top
wall 44 and side walls 46 and 48. In an alternate embodiment, protective layer
50
covers all the outer walls of core 40. Protective layer 50 is formed by
depositing a
film forming polymeric coating material onto walls 44, 46, and 48 of core 40.
The
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thickness of protective layer 50, in one exemplary embodiment, is between
about 0.5
mil to about 100 mils (about 12 micrometers to about 2500 micrometers). In
another
exemplary embodiment, the thickness of protective layer 50 is about 1.0 mil to
about
50 mils (about 25 micrometers to about 1250 micrometers), and in still another
exemplary embodiment, from about 5 mils to about 30 mils (about 125
micrometers
to about 750 micrometers). In an alternate embodiment, protective layer 50 is
formed
from a polymeric film laminated to at least one wall of core 40. The thickness
of the
laminated polymeric film of protective layer 50 is about 1 mil to about 150
mils
(about 25 micrometers to about 3750 micrometers).
[0017] Similar to reveal strips 38, and referring to Figure 4, each
chamfer strip 30, 32, 34, and 36 includes a core 52 formed from a foamed
polymeric
material and a protective layer 54 covering at least one outer wall of chamfer
strip
core 52. Similar to protective layer 50 described above, protective layer 54
is formed,
in one embodiment, by a film forming polymeric coating material, and in
another
embodiment, from a polymeric film laminated to at least one outer wall of
chamfer
strip core 52. Figure 4 illustrates chamfer strip 30; however, chamfer strips
32, 34,
and 36 have an identical structure. In the exemplary embodiment, each chamfer
strip
30, 32, 34, and 36 has a substantially triangular cross sectional shape and
includes a
first outer wall 56, a second outer wall 58, and a third outer wall 60.
[0018] Any suitable foamed polymeric material can be used to make
reveal strip core 40 and chamfer strip core 52. Suitable foams include, but
are not
limited to, polystyrene foams, polyvinyl chloride foams, polyurethane foams,
phenol-
formaldehyde foams, urea formaldehyde foams, polyisocyanurate foams,
polyolefin
foams, and mixtures thereof. Reveal strip core 40 and chamfer strip core 52,
in one
embodiment, are formed by cutting a foam blank into the desired shapes. In
another
embodiment, reveal strip core 40 and chamfer strip core 52 are formed by
extruding
the foamed polymeric material into the desired shapes. The foamed polymeric
material has a density, in one embodiment, of about 1 pound per cubic foot to
about 4
pounds per cubic foot. In another embodiment, the density is about 2 pounds to
about
3 pounds per cubic foot.
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[0019] Any suitable film forming polymeric coating material can be
used to form protective Layers 50 and 54. Suitable film forming polymeric
coating
materials include, but are not limited to, polyurethane coatings, poly urea
coatings,
epoxy coatings, plastisol coatings, vinyl coatings, acrylic coatings,
polyester coatings,
and mixtures thereof. The coating can be applied by any suitable application
method,
for example, spray coating, dip coating, curtain coating, roll coating and the
like. The
coating can be applied by automatic or manual application equipment.
[0020] The coating is applied, in one embodiment, to a dry film
thickness of about 12 micrometers to about 2500 micrometers, in another
embodiment, to a dry film thickness of about 25 micrometers to about 1250
micrometers, and in another embodiment, to a dry film thickness of about 125
micrometers to about 750 micrometers. In the exemplary embodiment, the coating
material is applied at 100 percent solids to minimize volatile emissions. In
other
embodiments, the coating material includes an appropriate solvent, for
example,
organic solvent or water, and is applied at a weight solids less than 100
percent, for
example, from about 50 percent to about 99 percent.
[0021] Any suitable polymeric material film can be used as a
laminate to form protective layers 50 and 54. Suitable polymeric material
films
include, but are not limited to polyurethane films, poly urea films, epoxy
films,
plastisol films, vinyl films, acrylic films, polyester films, polystyrene
films, and
mixtures thereof. The polymeric film can be applied by any suitable lamination
method, for example, vacuum forming, adhesive bonding, pressure forming,
thermal
forming, thermal stamping, and compression forming.
[0022] In one exemplary embodiment the polymeric film is
laminated to reveal strip core 40 and/or chamfer strip core 52 by heating a
sheet of
polymeric film to soften the film and then inserting the heated polymeric film
into a
backform template mold. Next, reveal strip core 40 and/or chamfer strip core
52 is
inserted into the backform template mold to laminate the polymeric film to
reveal
strip core 40 and/or chamfer strip core 52. The polymeric film is then cooled
and the
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laminated core 40 and/or 52 is removed from the mold. The excess polymeric
film is
then removed from core 40 and/or 52 by cutting and/or planning. In alternate
embodiments, a plurality of reveal strip cores 40 and/or chamfer strip cores
52 can be
laminated at one time by using a backform template mold that includes a
plurality of
core templates positioned side by side.
[0023) Concrete wall panel 10 is formed by assembling form 14 on
floor 28. Outer form members 18, 20, 22, and 24 are secured to floor 28 and
each
other to define the shape and size of panel 10. Chamfer strips 30, 32, 34, and
36 are
secured to floor 28 and outer form members 18, 20, 22, and 24 respectively by
any
suitable method, for example adhesive and/or adhesive tape. Reveal strips 38
are
positioned in casting area 26 and are attached to floor 28 with, for example
adhesive
and/or adhesive tape. Concrete is poured into mold 14 and permitted to harden
and
cure. Outer form members 18, 20, 22, and 24 are removed and concrete panel 10
is
lifted/tilted from floor 28 by, for example a crane. Any reveal strips 38 and
chamfer
strips that are embedded in the concrete are removed from panel 10 to form the
finished concrete wall panel 10.
[0024) While the invention has been described in terms of various
specific embodiments, those skilled in the art will recognize that the
invention can be
practiced with modification within the spirit and scope of the claims.
