Patent Application
20080066408
For the purpose of the description hereinafter, the terms “upper,” “lower,” “inner”, “outer”, “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” and derivatives thereof, shall relate to the invention as oriented in the drawing Figures. However, it is to be understood that the invention may assume alternate variations and step sequences except where expressly specified to the contrary. It is also to be understood that the specific devices and processes, illustrated in the attached drawings and described in the following specification, is an exemplary embodiment of the present invention. Hence, specific dimensions and other physical characteristics related to the embodiment disclosed herein are not to be considered as limiting the invention. In describing the embodiments of the present invention, reference will be made herein to the drawings in which like numerals refer to like features of the invention.
Other than where otherwise indicated, all numbers or expressions referring to quantities, distances, or measurements, etc. used in the specification and claims are to be understood as modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties, which the present invention desires to obtain. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective measurement methods.
Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between and including the recited minimum value of 1 and the recited maximum value of 10; that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. Because the disclosed numerical ranges are continuous, they include every value between the minimum and maximum values. Unless expressly indicated otherwise, the various numerical ranges specified in this application are approximations.
As used herein, the term “expandable polymer matrix” refers to a polymeric material in particulate or bead form that is impregnated with a blowing agent such that when the particulates and/or beads are placed in a mold and heat is applied thereto, evaporation of the blowing agent (as described below) effects the formation of a cellular structure and/or an expanding cellular structure in the particulates and/or beads and the outer surfaces of the particulates and/or beads fuse together to form a continuous mass of polymeric material conforming to the shape of the mold.
As used herein, the term “polymer” is meant to encompass, without limitation, homopolymers, copolymers and graft copolymers.
As used herein, the terms “(meth)acrylic” and “(meth)acrylate” are meant to include both acrylic and methacrylic acid derivatives, such as the corresponding alkyl esters often referred to as acrylates and (meth)acrylates, which the term “(meth)acrylate” is meant to encompass.
The present invention provides a concrete wall forming system that includes a plurality of interconnected mold units for forming a wall by receiving concrete therein.
The mold units are made of a foamed plastic that can be produced by expanding an expandable polymer matrix. The expanded polymer matrix is typically molded from expandable thermoplastic particles. These expandable thermoplastic particles are made from any suitable thermoplastic homopolymer or copolymer. Particularly suitable for use are homopolymers derived from vinyl aromatic monomers including styrene, isopropylstyrene, alpha-methylstyrene, nuclear methylstyrenes, chlorostyrene, tert-butylstyrene, and the like, as well as copolymers prepared by the copolymerization of at least one vinyl aromatic monomer as described above with one or more other monomers, non-limiting examples being divinylbenzene, conjugated dienes (non-limiting examples being butadiene, isoprene, 1,3- and 2,4-hexadiene), alkyl methacrylates, alkyl acrylates, acrylonitrile, and maleic anhydride, wherein the vinyl aromatic monomer is present in at least 50% by weight of the copolymer. In an embodiment of the invention, styrenic polymers are used, particularly polystyrene. However, other suitable polymers can be used, such as polyolefins (e.g. polyethylene, polypropylene), polycarbonates, polyphenylene oxides, and mixtures thereof.
In a particular embodiment of the invention, the expandable thermoplastic particles are expandable polystyrene (EPS) particles. These particles can be in the form of beads, granules, or other particles convenient for the expansion and molding operations. Particles polymerized in an aqueous suspension process are essentially spherical and are useful for molding the mold units and/or forms described herein below. These particles can be screened so that their size ranges from about 0.008 inches (0.2 mm) to about 0.16 inches (4 mm).
In an embodiment of the invention, resin beads (unexpanded) containing any of the polymers or polymer compositions described herein have a particle size of at least 0.2 mm, in some situations at least 0.33 mm, in some cases at least 0.35 mm, in other cases at least 0.4 mm, in some instances at least 0.45 mm and in other instances at least 0.5 mm. Also, the resin beads can have a particle size of up to about 4 mm, in some situations up to about 3.5 mm, in other situations up to about 3 mm, in some instances up to 2 mm, in other instances up to 2.5 mm, in some cases up to 2.25 mm, in other cases up to 2 mm, in some situations up to 1.5 mm and in other situations up to 1 mm. The resin beads used in this embodiment can be any value or can range between any of the values recited above.
The average particle size and size distribution of the expandable resin beads or pre-expanded resin beads can be determined using low angle light scattering, which can provide a weight average value. As a non-limiting example, a Model LA-910 Laser Diffraction Particle Size Analyzer available from Horiba Ltd., Kyoto, Japan can be used
As used herein, the terms “expandable thermoplastic particles” or “expandable resin beads” refers to a polymeric material in particulate or bead form that is impregnated with a blowing agent such that when the particulates and/or beads are placed in a mold or expansion device and heat is applied thereto, evaporation of the blowing agent (as described below) effects the formation of a cellular structure and/or an expanding cellular structure in the particulates and/or beads. When expanded in a mold, the outer surfaces of the particulates and/or beads fuse together to form a continuous mass of polymeric material conforming to the shape of the mold.
As used herein, the terms “pre-expanded thermoplastic particles,” “pre-expanded resin beads,” or “prepuff” refers to expandable resin beads that have been expanded, but not to their maximum expansion factor and whose outer surfaces have not fused. As used herein, the term “expansion factor” refers to the volume a given weight of resin bead occupies, typically expressed as cc/g. Pre-expanded resin beads can be further expanded in a mold where the outer surfaces of the pre-expanded resin beads fuse together to form a continuous mass of polymeric material conforming to the shape of the mold.
The expandable thermoplastic particles can be impregnated using any conventional method with a suitable blowing agent. As a non-limiting example, the impregnation can be achieved by adding the blowing agent to the aqueous suspension during the polymerization of the polymer, or alternatively by re-suspending the polymer particles in an aqueous medium and then incorporating the blowing agent as taught in U.S. Pat. No. 2,983,692. Any gaseous material or material which will produce gases on heating can be used as the blowing agent. Conventional blowing agents include aliphatic hydrocarbons containing 4 to 6 carbon atoms in the molecule, such as butanes, pentanes, hexanes, and the halogenated hydrocarbons, e.g. CFC's and HCFC'S, which boil at a temperature below the softening point of the polymer chosen. Mixtures of these aliphatic hydrocarbon blowing agents can also be used.
Alternatively, water can be blended with these aliphatic hydrocarbons blowing agents or water can be used as the sole blowing agent as taught in U.S. Pat. Nos. 6,127,439; 6,160,027; and 6,242,540 in these patents, water-retaining agents are used. The weight percentage of water for use as the blowing agent can range from 1 to 20%. The texts of U.S. Pat. Nos. 6,127,439, 6,160,027 and 6,242,540 are incorporated herein by reference.
The impregnated thermoplastic particles are generally pre-expanded to a density of at least 0.5 lb/ft3, in some cases at least 0.75 lb/ft3, in other cases at least 1.0 lb/ft3, in some situations at least 1.25 lb/ft3, in other situations at least 1.5 lb/ft3, and in some instances at least about 1.75 lb/ft3. Also, the density of the impregnated pre-expanded particles can be up to 12 lb/ft3, in some cases up to 10 lb/ft3, and in other cases up to 5 lb/ft3. The density of the impregnated pre-expanded particles can be any value or range between any of the values recited above. The pre-expansion step is conventionally carried out by heating the impregnated beads via any conventional heating medium, such as steam, hot air, hot water, or radiant heat. One generally accepted method for accomplishing the pre-expansion of impregnated thermoplastic particles is taught in U.S. Pat. No. 3,023,175.
The impregnated thermoplastic particles can be foamed cellular polymer particles as taught in U.S. patent application Ser. No. 10/021,716, the teachings of which are incorporated herein by reference. The foamed cellular particles can be polystyrene that are pre-expanded and contain a volatile blowing agent at a level of less than 14 wt %, in some situations less than 8 wt %, in some cases ranging from about 2 wt % to about 7 wt %, and in other cases ranging from about 2.5 wt % to about 6.5 wt % based on the weight of the polymer.
The thermoplastic particles according to the invention can include an interpolymer of a polyolefin and in situ polymerized vinyl aromatic monomers. Non-limiting examples of such interpolymers are disclosed in U.S. Pat. Nos. 4,303,756 and 4,303,757 and U.S. Application Publication 2004/0152795, the relevant portions of which are herein incorporated by reference. A non-limiting example of interpolymers that can be used in the present invention include those available under the trade name ARCEL®, available from NOVA Chemicals Inc., Pittsburgh, Pa. and PIOCELAN®, available from Sekisui Plastics Co., Ltd., Tokyo, Japan.
The expanded polymer matrix can include customary ingredients and additives, such as pigments, dyes, colorants, plasticizers, mold release agents, stabilizers, ultraviolet light absorbers, mold prevention agents, antioxidants, and so on. Typical pigments include, without limitation, inorganic pigments such as carbon black, graphite, expandable graphite, zinc oxide, titanium dioxide, and iron oxide, as well as organic pigments such as quinacridone reds and violets and copper phthalocyanine blues and greens.
In a particular embodiment of the invention the pigment is carbon black, a non-limiting example of such a material being EPS SILVER®, available from NOVA Chemicals Inc.
In another particular embodiment of the invention the pigment is graphite, a non-limiting example of such a material being NEOPOR®, available from BASF Aktiengesellschaft Corp., Ludwigshafen am Rhein, Germany.
The pre-expanded particles or “pre-puff” are usually heated in a closed mold to form the present mold units.
In another embodiment of the invention, the mold units can have a male “tongue” edge and a female “groove” edge that facilitates a “tongue and groove” union of two matching mold units. In other embodiments of the invention, the mold units can have overlapping lip ends adapted to join matching mold units together.
In embodiments of the invention shown in
Top surface 22 of mold unit 10 includes a first portion bond beam form 28 extending into body 12 lengthwise and defined by a top depression 30 extending transversely to the length of body 12, first end 18, and second end 20. First top ledge 32 extends lengthwise along the body from first side 14 to top depression 30 and includes a first top lip seal portion 34. Second top ledge 36 extends lengthwise along body 14 from second side 16 to top depression 30 and includes second top lip seal portion 38.
Bottom surface 24 includes second portion bond beam form 38 extending into body 12 lengthwise and defined by a bottom depression 40 extending transversely to the length of body 12, first end 18, and second end 20. First bottom ledge 42 extends lengthwise along body 12 from first side 14 to first bottom lip seal portion 44, which in turn extends to bottom depression 40. Second bottom ledge 46 extends lengthwise along body 12 from second side 16 to second bottom lip seal portion 48, which extends to bottom depression 40.
Column forms 26 extend from top depression 30 to bottom depression 40.
First top lip seal portion 34 and first bottom lip seal portion 44 are adapted to form a first seal with first top ledge 32 and first bottom ledge 32 respectively. Second top lip seal portion 38 and second bottom lip seal portion 48 are adapted to form a second seal with second top ledge 36 and second bottom ledge 46 respectively. Thus the mold units are adapted to form at least two seals between two mold units such that the first portion bond beam form and second portion bond beam form are combined to form a bond beam form.
In an embodiment of the invention, first end 18 includes a first extended portion 47 and a first recessed portion 49 and second end 20 includes a second extended portion 45 adapted to be received by first recessed portion 49 and a second recessed portion 43 adapted to receive first extended portion 47 to facilitates a union between corresponding mold units 12.
As indicated above, body 12 can contain an expanded polymer matrix. As such, body 12 can have a density of at least about 0.5 lb/ft3, in some cases at least about 0.75 lb/ft3, in other cases at least about 1.0 lb/ft3, in some situations at least about 1.25 lb/ft3, and in other situations at least about 1.5 lb/ft3. Also, the density of the impregnated pre-expanded particles can be up to about 12 lb/ft3, in some cases up to about 10 lb/ft3, in other cases up to about 5 lb/ft3, in some instances up to up to about 3 lb/ft3, and in other instances at up to about 1.75 lb/ft3. The density of the impregnated pre-expanded particles can be any value or range between any of the values recited above.
Top depression 30 and bottom depression 40 can be combined to provide any suitable cross-sectional shape that will provide a concrete web having desired properties, such as strength, weight and concrete usage. As such, top depression 30 and bottom depression 40 each have a cross sectional shape that provides a matching portion of a desired concrete beam cross-sectional shape. Non-limiting examples of desired cross-sectional beam shapes include circular, oval, elliptical, triangular, square, rectangular, hexagonal, and octagonal. In an embodiment of the invention, each of top depression 30 and bottom depression 40 have a concave cross-sectional shape that provides a concrete beam having a circular, oval, or elliptical cross-sectional shape.
In embodiments of the invention, top depression 30 and bottom depression 40 have a generally curved shape and have a minimum dimension 41, defined herein as the distance between top depression 30 and bottom depression 40 at their closest point or proximity to each other (see
In an embodiment of the invention, top depression 30 and bottom depression 40 each have a concave shape.
In embodiments of the invention, the present concrete wall forming system includes a plurality of linear mold units 10 as described above and one or more corner units as shown in
Top corner surface 62 includes a first portion top corner bond beam form 68 and a second portion top corner bond beam 74. First portion top corner bond beam form 68 extends into the body lengthwise and defined by a lengthwise top depression 70 extending transversely to the length of body 52, first end 58, and wall 72 at second end 60, which includes a top wall ledge 64 and a top wall lip seal portion 66. Second portion top corner bond beam form 74 extends into body 52 crosswise and defined by a crosswise top depression 76 extending from lengthwise top depression 70, wall 72 at second end 60 and a terminal portion 78 of first top ledge 80.
First top ledge 80 extends lengthwise along body 52 from second side 56 to lengthwise top depression 70 and from crosswise top depression 76 to first end 58 and includes first top lip seal portion 82.
Second top ledge 84 extends lengthwise along body 52 from first side 54 to lengthwise top depression 70 and includes a second top lip seal portion 86.
Bottom corner surface 64 includes a first portion bottom corner bond beam form 88 extending into body 52 lengthwise and defined by a lengthwise bottom depression 90 extending transversely to the length of body 52, first end 58, and wall 72 at second end 60, which includes first bottom wall lip seal portion 92. Second portion bottom corner bond beam form 94 extends into body 52 crosswise and is defined by crosswise bottom depression 96 extending from lengthwise bottom depression 90, wall 72 at second end 60, first side 54 and a terminal portion 98 of a first bottom ledge 100.
First bottom ledge 100 extends lengthwise along body 52 from second side 56 to lengthwise bottom depression 90 and from wall 72 to first end 58 and a first bottom lip seal 102 extends along first bottom ledge 100.
Second bottom ledge 104 extends lengthwise along body 52 from first side 54 to bottom depression 90 and from first end 58 to crosswise bottom depression 96 includes a second bottom lip seal portion 106.
Column forms 66 extend from top depression 70 bottom depression 90.
First top lip seal portion 82 and first bottom lip seal portion 102 are adapted to form a first seal between two mold units and the second top lip seal portion 86 and second bottom lip seal portion 106 are adapted to form a second seal between two mold units such that the first portion top corner bond beam 68 and first portion bottom bond beam form 88 and second portion top corner bond beam form 74 and second portion bottom bond beam form 94 combine to form a corner bond beam form.
In an embodiment of the invention, as shown in
When mold units are arrayed as shown in
As shown in
Mold units 10 and corner units 50 can have any suitable length that allows for ease of manufacture and transportation. As such, mold units 10 and corner units 50 can independently have a length measured from first end 18 to second end 20 or first corner end 58 to second corner end 60 respectively of from at least about 2 feet (0.6 m), in some cases at least about 2.5 feet (0.76 m) and in other cases at least about 3 feet (0.91 m) and can be up to about 10 feet (3 m), in some cases up to about 8 feet (2.4 m) and in other cases up to about 6 feet (1.8 m). The length of mold units 10 and corner units 50 can independently by any of the values or range between any of the values recited above.
Mold units 10 and corner units 50 can have any suitable width based on the design properties of the desired insulated concrete wall to be erected. As such, mold units 10 and corner units 50 can independently have a width measured from first side 14 to second side 16 or first corner side 54 to second corner side 56 respectively of from at least about 4 in. (10.2 cm), in some cases at least about 6 in. (15.2 in) and in other cases at least about 7 inches (18 cm) and can be up to about 24 inches (61 cm), in some cases up to about 20 inches (51 cm) and in other cases up to about 16 inches (41 cm). The width of mold units 10 and corner units 50 can independently by any of the values or range between any of the values recited above.
Mold units 10 and corner units 50 can have a vertical height of at least about 4 in. (10.2 cm), in some cases at least about 6 in. (15.2 in) and in other cases at least about 8 inches (20.4 cm) and can be up to about 24 in. (61 cm), in some cases up to about 20 in. (51 cm) and in other cases up to about 16 in. (41 cm). The vertical height of mold units 10 and corner units 50 is determined by the intended number of courses of mold units 10 and corner units 50 to be used in an overall insulated concrete wall design. The Vertical height of mold units 10 and corner units 50 can be any value or range between any of the values recited above.
The bond beam formed by combining first portion bond beam form 28 and second portion bond beam form 38; first portion top corner bond beam form 68 and second portion top corner bond beam 74; and/or second portion top corner bond beam form 74 and second portion bottom corner bond-beam form 94 can have any suitable cross-sectional shape so long as the resulting concrete beam can provide desired strength characteristics. As such, the cross-sectional shape can be selected from U-shaped, trapezoidal, circular, oval, elliptical, triangular, square, rectangular, hexagonal, and octagonal.
The cross-sectional area of the bond beam formed by combining first portion bond beam form 28 and second portion bond beam form 38; first portion top corner bond beam form 68 and second portion top corner bond beam 74; and second portion top corner bond beam form 74 and/or second portion bottom corner bond beam form 94 column forms 34 is determined based on the load bearing design of the resulting insulated concrete wall. The cross-sectional area of the bond beam forms can be at least about 8 in2 (52 cm2), in some cases at least about 12 in2 (77 cm2) and in other cases at least about 16 in2 (103 cm) and can be up to about 80 in2 (516 cm), in some cases up to about 60 in2 (387 cm2), and in other cases up to about 40 in2 (258 cm2). The cross-sectional area of the bond beam can be any value or range between any of the values recited above.
In embodiments of the invention, the cross-sectional shape of the bond beam is circular having a diameter of at least about 2 inches (5 cm) and in some cases at least about 3 inches (7.5 cm) and can be up to 7.5 inches about (19 cm), in some cases up to about 7 inches (18 cm) and in other cases up to about 6 inches (15 cm) based on the load bearing design of the resulting insulated concrete wall. The diameter of the circular cross-sectional shape of the bond beam can be any value or range between any of the values recited above.
In embodiments of the invention, the cross-sectional shape of the bond beam is that of an ellipse. As used herein, an ellipse is an oval shape defined by a major axis and a minor axis, perpendicular to the major axis and passing through the center of the ellipse, both terminating at the edge of the ellipse. The major axis is the longest segment that passes through the ellipse. The ellipse can be characterized by the ratio of the major axis to the minor axis (aspect ratio). For a circle, the aspect ratio is 1.
The major axis can have a length of at least about 2 inches (5 cm) and in some cases at least about 3 inches (7.5 cm) and can be up to 7.5 inches about (19 cm), in some cases up to about 7 inches (18 cm) and in other cases up to about 6 inches (15 cm) based on the load bearing design of the resulting insulated concrete wall. The length of the major axis of the ellipse-shaped bond beam form can be any value or range between any of the values recited above.
The aspect ratio of the ellipse-shaped bond beam form can be at least about 1.1, in some cases at least about 1.2, and in other cases at least about 1.3 and the aspect ratio can be up to about 3, in some cases up to about 2 and in other cases up to about 1.75. The aspect ratio of the ellipse-shaped bond beam form can be any value or range between any of the values recited above.
Each of column forms 26 and 66 can independently have any suitable cross-sectional shape so long as the resulting concrete column can provide desired strength characteristics. As such, the cross-sectional shape can be selected from trapezoidal, circular, oval, elliptical, triangular, square, rectangular, hexagonal, and octagonal.
The cross-sectional area of column forms 26 and 66 is determined based on the load bearing design of the resulting insulated concrete wall. The cross-sectional area of column forms 26 and 66 can be at least about 8 in2 (52 cm2), in some cases at-least about 12 in2 (77 cm2) and in other cases at least about 16 in2 (103 cm2) and can be up to about 80 in2 (516 cm2), in some cases up to about 60 in2 (387 cm2), and in other cases up to about 40 in2 (258 cm2). The cross-sectional area of column forms 26 and 66 can be any value or range between any of the values recited above.
In embodiments of the invention, the cross-sectional shape of column forms 26 and 66 is circular having a diameter of at least about 2 inches (5 cm) and in some cases at least about 3 inches (7.5 cm) and can be up to 7.5 inches about (19 cm), in some cases up to about 7 inches (18 cm) and in other cases up to about 6 inches (15 cm) based on the load bearing design of the resulting insulated concrete wall. The diameter of the circular column forms 26 and 66 can be any value or range between any of the values recited above.
In embodiments of the invention, molds 10 and 50 are designed so column forms 26 and 66 are evenly spaced as defined by the distance between the centers of each adjacent column forms. As such the column forms can be at least about 4.5 inches (11.5 cm) and in some cases at least about 6.5 inches (16.5 cm) and can be up to about 16 inches (41 cm), in some cases up to about 15 inches (38 cm) and in other cases up to about 13 inches (33 cm) on center based on the load bearing design of the resulting insulated concrete wall.
In embodiments of the invention, one or more courses of mold units 10 and corner units 50 can be used to provide a concrete wall forming system. As a non-limiting example shown in
Proper alignment of mold units 10 provide for the formation of three course column forms 214 and a series of bond beam forms, bottom partial bond beam form 206, first bond beam form 208, second bond beam form 210, and top partial bond beam form 212.
As noted above, first top lip seal portion 34 and first bottom lip seal portion 44 are adapted to form a first seal with first bottom ledge 42 and first top ledge 32 respectively. Second top lip seal portion 38 and second bottom lip seal portion 48 are adapted to form a second seal with second bottom ledge 46 and second top ledge 36 respectively. The continuous seal that is formed is held in place by the weight of the concrete poured within mold unit forms and provides improved concrete leakage prevention when compared with prior art systems. In embodiments of the invention, if the surface that multi-course wall form system 201 rests on is uneven resulting in less than a flush interface between first top lip seal portion 34 and first bottom ledge 42, first bottom lip seal portion 44 and first top ledge 32, second top lip seal portion 38 and second bottom ledge 46, and/or second bottom lip seal portion 48 and second top ledge 36, spray foam, as is known in the art, can be used to fill any gaps.
As was mentioned above, proper alignment of mold units 10 provides for three course column forms 214. Proper alignment of mold units 10 is provided by the design of lip seal portions 34, 38, 44 and 48 and ledges 32, 36, 42 and 46. Referring to
Similarly, corner units 50 can be aligned using bumps 224 and indents 226.
As shown in
As those skilled in the art will appreciate, various numbers of courses can be used to provide a plurality of concrete beams and columns according to the invention. Also, various insulated concrete wall system layouts can be designed with one or more courses of mold units. As a non-limiting example, the three course wall system of
As such, the present invention provides a wall that includes one or more rows of the concrete wall forming systems as described above where concrete is poured into and set in the bond beam forms, partial bond beam forms and column forms in the mold units.
Embodiments of the invention provide a continuous wall that includes the above-described concrete wall forming system, where concrete is poured into and set in the partial bond beam forms and column forms in the mold units.
Often, in order to add strength to an insulated concrete wall system, concrete reinforcing products are placed within the bond beam forms, partial bond beam forms and/or column forms described above.
In embodiments of the invention, the concrete reinforcing product can be selected from rebar, fiber reinforced polymer, carbon fibers, aramid fibers, glass fibers, metal fibers and combinations thereof.
As used herein, the term “fiber reinforced polymer” refers to plastics that include, but are not limited to reinforced thermoplastics and reinforced thermoset resins. Thermoplastics include polymers and polymers made up of materials that can be repeatedly softened by heating and hardened again on cooling. Suitable thermoplastic polymers include, but are not limited to homopolymers and copolymers of styrene, homopolymers and copolymers of C2 to C20 olefins, C4 to C20 dienes, polyesters, polyamides, homopolymers and copolymers of C2 to C20 (meth)acrylate esters, polyetherimides, polycarbonates, polyphenylethers, polyvinylchlorides, polyurethanes, and combinations thereof.
Suitable thermoset resins are resins that when heated to their cure point, undergo a chemical cross-linking reaction causing them to solidify and hold their shape rigidly, even at elevated temperatures. Suitable thermoset resins include, but are not limited to alkyd resins, epoxy resins, diallyl phthalate resins, melamine resins, phenolic resins, polyester resins, urethane resins, and urea, which can be crosslinked by reaction, as non-limiting examples, with diols, triols, polyols, and/or formaldehyde.
Fiber reinforcing materials that can be incorporated into the thermoplastics and/or thermoset resins include, but are not limited to carbon fibers, aramid fibers, glass fibers, metal fibers, woven fabric or structures of the mentioned fibers, and/or fiberglass, and can optionally include one or more fillers, non-limiting examples including carbon black, graphite, clays, calcium carbonate, titanium dioxide, and combinations thereof.
In an embodiment of the invention shown in
In certain embodiments of the invention, mold units 10 and 50 are designed to minimize stress concentrations in order to reduce the risk of deformation and fracture when concrete is plated in the mold units. In these embodiments, the internal column form surfaces are designed as cylinders so that the lateral pressure from the concrete is as evenly distributed within the mold unit as possible. This is an improvement over prior art all-foam ICFs, where the internal surfaces have squared edges, which can lead to stress concentrations at the corners. By eliminating the stress concentrations in the present wall forming system, the pressure at which deformation and/or failure occurs is increased, reducing the likelihood of deformation and/or failure of the wall forming system. Ultimately, this allows the ICF to be made from lower density foam (for the same performance as a higher density with another design)and subsequently at a lower cost.
In particular embodiments of the invention, mold units 10 and 50 are designed to optimally meet International Residential Code standards for screen grid ICFs. As such the column forms of mold units 10 and 50 are cylinders having a diameter of from about 5 inches (12.7 cm) to about 6 inches (15.2 cm), in some cases about 5.5 inches (14 cm) spaced apart by about 7 inches (18 cm) to about 9 inches (23 cm), in some cases about 8 inches (20.3 cm) on center. The dimensions of mold units 10 and 50 in this embodiment are length of from about 40 inches (102 cm) to about 56 inches (142 cm), in some cases about 48 inches (122 cm); width of from about 7 inches (18 cm) to about 9 inches (23 cm), in some cases about 8 inches (20.3 cm); and height of from about 10 inches (25.4 cm) to about 14 inches (35.5 cm), in some cases about 12 inches (30.5 cm). The bond beam cross sectional shape is an ellipse having a major axis of from about 5 inches (12.7 cm) to about 6 inches (15.2 cm), in some cases about 5.5 inches (14 cm) and an aspect ratio of from about 1.25 to about 1.5, in some cases about 1.375. In this embodiment, minimum dimension 41 is about 7 inches (18 cm) to about 9 inches (23 cm), in some cases about 8 inches (20.3 cm).
Any suitable type of concrete can be used to make the concrete walls and concrete wall systems described herein. The specific type of concrete will depend on the desired and designed properties of the concrete walls and concrete wall systems. In embodiments of the invention, the concrete includes one or more hydraulic cement compositions selected from Portland cements, pozzolana cements, gypsum cements, aluminous cements, magnesia cements, silica cements, and slag cements.
In an embodiment of the invention, the cement includes a hydraulic cement composition. The hydraulic cement composition can be present at a level of at least 3, in certain situations at least 5, in some cases at least 7.5, and in other cases at least 9 volume percent and can be present at levels up to 40, in some cases up to 35, in other cases up to 32.5, and in some instances up to 30 volume percent of the cement mixture. The cement mixture can include the hydraulic cement composition at any of the above-stated levels or at levels ranging between any of levels-stated above.
In an embodiment of the invention, the concrete mixture can optionally include other aggregates and adjuvants known in the art including but not limited to sand, additional aggregate, plasticizers and/or fibers. Suitable fibers include, but are not limited to glass fibers, silicon carbide, aramid fibers, polyester, carbon fibers, composite fibers, fiberglass, metal and combinations thereof as well as fabric containing the above-mentioned fibers, and fabric containing combinations of the above-mentioned fibers.
Non-limiting examples of fibers that can be used in the invention include MeC-GRID® and C-GRID® available from TechFab, LLC, Anderson, S.C., KEVLAR® available from E.I. du Pont de Nemours and Company, Wilmington Del., TWARON® available from Teijin Twaron B.V., Arnheim, the Netherlands, SPECTRA® available from Honeywell International Inc., Morristown, N.J., DACRON® available from Invista North America S.A.R.L. Corp. Wilmington, Del., and VECTRAN® available from Hoechst Celanese Corp., New York, N.Y. The fibers can be used in a mesh structure, intertwined, interwoven, and oriented in any desirable direction.
In a particular embodiment of the invention fibers can make up at least 0.1, in some cases at least 0.5, in other cases at least 1, and in some instances at least 2 volume percent of the concrete composition. Further, fibers can provide up to 10, in some cases up to 8, in other cases up to 7, and in some instances up to 5 volume percent of the concrete composition. The amount of fibers is adjusted to provide desired properties to the concrete composition. The amount of fibers can be any value or range between any of the values recited above.
Further to this embodiment, the additional aggregate can include, but is not limited to, one or more materials selected from common aggregates such as sand, stone, and gravel. Common lightweight aggregates can include ground granulated blast furnace slag, fly ash, glass, silica, expanded slate and clay; insulating aggregates such as pumice, perlite, vermiculite, scoria, and diatomite; light-weight aggregate such as expanded shale, expanded slate, expanded clay, expanded slag, fumed silica, pelletized aggregate, extruded fly ash, tuff, and macrolite; and masonry aggregate such as expanded shale, clay, slate, expanded blast furnace slag, sintered fly ash, coal cinders, pumice, scoria, and pelletized aggregate.
When included, the other aggregates and adjuvants are present in the concrete mixture at a level of at least 0.5, in some cases at least 1, in other cases at least 2.5, in some instances at least 5 and in other instances at least 10 volume percent of the concrete mixture. Also, the other aggregates and adjuvants can be present at a level of up to 95, in some cases up to 90, in other cases up to 85, in some instances up to 65 and in other instances up to 60 volume percent of the concrete mixture. The other aggregates and adjuvants can be present in the concrete mixture at any of the levels indicated above or can range between any of the levels indicated above.
In embodiments of the invention, the concrete compositions can contain one or more additives, non-limiting examples of such being anti-foam agents, water-proofing agents, dispersing agents, set-accelerators, set-retarders, plasticizing agents, superplasticizing agents, freezing point decreasing agents, adhesiveness-improving agents, and colorants. The additives are typically present at less than one percent by weight with respect to total weight of the composition, but can be present at from 0.1 to 3 weight percent.
Suitable dispersing agents or plasticizers that can be used in the invention include, but are not limited to hexametaphosphate, tripolyphosphate, polynaphthalene sulphonate, sulphonated polyamine and combinations thereof.
Suitable plasticizing agents that can be used in the invention include, but are not limited to polyhydroxycarboxylic acids or salts thereof, polycarboxylates or salts thereof; lignosulfonates, polyethylene glycols, and combinations thereof.
Suitable superplasticizing agents that can be used in the invention include, but are not limited to alkaline or earth alkaline metal salts of lignin sulfonates; lignosulfonates, alkaline or earth alkaline metal salts of highly condensed naphthalene sulfonic acid/formaldehyde condensates; polynaphthalene sulfonates, alkaline or earth alkaline metal salts of one or more polycarboxylates (such as poly(meth)acrylates and the polycarboxylate comb copolymers described in U.S. Pat. No. 6,800,129, the relevant portions of which are herein incorporated by reference); alkaline or earth alkaline metal salts of melamine/formaldehyde/sulfite condensates; sulfonic acid esters; carbohydrate esters; and combinations thereof.
Suitable set-accelerators that can be used in the invention include, but are not limited to soluble chloride salts (such as calcium chloride), triethanolamine, paraformaldehyde, soluble formate salts (such as calcium formate), sodium hydroxide, potassium hydroxide, sodium carbonate, sodium sulfate, 12CaO.7Al2O3, sodium sulfate, aluminum sulfate, iron sulfate, the alkali metal nitrate/sulfonated aromatic hydrocarbon aliphatic aldehyde condensates disclosed in U.S. Pat. No. 4,026,723, the water soluble surfactant accelerators disclosed in U.S. Pat. No. 4,298,394, the methylol derivatives of amino acids accelerators disclosed in U.S. Pat. No. 5,211,751, and the mixtures of thiocyanic acid salts, alkanolamines, and nitric acid salts disclosed in U.S. Pat. No. Re. 35,194, the relevant portions of which are herein incorporated by reference, and combinations thereof.
Suitable set-retarders that can be used in the invention include, but are not limited to lignosulfonates, hydroxycarboxylic acids (such as gluconic acid, citric acid, tartaric acid, malic acid, salicylic acid, glucoheptonic acid, arabonic acid, acid, and inorganic or organic salts thereof such as sodium, potassium, calcium, magnesium, ammonium and triethanolamine salt), cardonic acid, sugars, modified sugars, phosphates, borates, silico-fluorides, calcium bromate, calcium sulfate, sodium sulfate, monosaccharides such as glucose, fructose, galactose, saccharose, xylose, apiose, ribose and invert sugar, oligosaccharides such as disaccharides and trisaccharides, such oligosaccharides as dextrin, polysaccharides such as dextran, and other saccharides such as molasses containing these; sugar alcohols such as sorbitol; magnesium silicofluoride; phosphoric acid and salts thereof, or borate esters; aminocarboxylic acids and salts thereof; alkali-soluble proteins; humic acid; tannic acid; phenols; polyhydric alcohols such as glycerol; phosphonic acids and derivatives thereof, such as aminotri(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and alkali metal or alkaline earth metal salts thereof, and combinations of the set-retarders indicated above.
Suitable defoaming agents that can be used in the invention include, but are not limited to silicone-based defoaming agents (such as dimethylpolysiloxane, diemthylsilicone oil, silicone paste, silicone emulsions, organic group-modified polysiloxanes (polyorganosiloxanes such as dimethylpolysiloxane), fluorosilicone oils, etc.), alkyl phosphates (such as tributyl phosphate, sodium octylphosphate, etc.), mineral oil-based defoaming agents (such as kerosene, liquid paraffin, etc.), fat- or oil-based defoaming agents (such as animal or vegetable oils, sesame oil, castor oil, alkylene oxide adducts derived there from, etc.), fatty acid-based defoaming agents (such as oleic acid, stearic acid, and alkylene oxide adducts derived there from, etc.), fatty acid ester-based defoaming agents (such as glycerol monoricinolate, alkenylsuccinic acid derivatives, sorbitol monolaurate, sorbitol trioleate, natural waxes, etc.), oxyalkylene type defoaming agents, alcohol-based defoaming agents: octyl alcohol, hexadecyl alcohol, acetylene alcohols, glycols, etc.), amide-based defoaming agents (such as acrylate polyamines, etc.), metal salt-based defoaming agents (such as aluminum stearate, calcium oleate, etc.) and combinations of the above-described defoaming agents.
Suitable freezing point decreasing agents that can be used in the invention include, but are not limited to ethyl alcohol, calcium chloride, potassium chloride, and combinations thereof.
Suitable adhesiveness-improving agents that can be used in the invention include, but are not limited to polyvinyl acetate, styrene-butadiene, homopolymers and copolymers of (meth)acrylate esters, and combinations thereof.
Suitable water-repellent or water-proofing agents that can be used in the invention include, but are not limited to fatty acids (such as stearic acid or oleic acid), lower alkyl fatty acid esters (such as butyl stearate), fatty acid salts (such as calcium or aluminum stearate), silicones, wax emulsions, hydrocarbon resins, bitumen, fats and oils, silicones, paraffins, asphalt, waxes,and combinations thereof. Although not used in many embodiments of the invention, when used suitable air-entraining agents include, but are not limited to vinsol resins, sodium abietate, fatty acids and salts thereof, tensides, alkyl-aryl-sulfonates, phenol ethoxylates, lignosulfonates, and mixtures thereof.
In some embodiments of the invention, the concrete is light-weight concrete. As used herein, the term “light weight concrete” refers to concrete where light-weight aggregate is included in a cementitous mixture. Exemplary light weight concrete compositions that can be used in the present invention are disclosed in U.S. Pat. Nos. 3,021,291, 3,214,393, 3,257,338, 3,272,765, 5,622,556, 5,725,652, 5,580,378, and 6,851,235, JP-9 071 449, WO 98 02 397, WO 00/61519, and WO 01/66485 the relevant portions of which are incorporated herein by reference.
In particular embodiments of the present invention, the lightweight concrete (LWC) composition includes a concrete mixture and polymer particles. In many instances the size, composition, structure, and physical properties of expanded polymer particles, and in some instances their resin bead precursors, can greatly affect the physical properties of LWC used in the invention. Of particular note is the relationship between bead size and expanded polymer particle density on the physical properties of the resulting LWC wall.
The polymer particles, which can optionally be expanded polymer particles, are present in the LWC composition at a level of at least 10, in some instances at least 15, in other instances at least 20, in particular situations up to 25, in some cases at least 30, and in other cases at least 35 volume percent and up to 90, in some cases up to 85, in other cases up to 78, in some instances up to 75, in other instance up to 65, in particular instances up to 60, in some cases up to 50, and in other cases up to 40 volume percent based on the total volume of the LWC composition. The amount of polymer particles will vary depending on the particular physical properties desired in a finished LWC wall. The amount of polymer particles in the LWC composition can be any value or can range between any of the values recited above.
The polymer particles can include any particles derived from any suitable expandable thermoplastic material. The actual polymer particles are selected based on the particular physical properties desired in a finished LWC wall. As a non-limiting example, the polymer particles, which can optionally be expanded polymer particles, can include one or more polymers selected from homopolymers of vinyl aromatic monomers; copolymers of at least one vinyl aromatic monomer with one or more of divinylbenzene, conjugated dienes, alkyl methacrylates, alkyl acrylates, acrylonitrile, and/or maleic anhydride; polyolefins; polycarbonates; polyesters; polyamides; natural rubbers; synthetic rubbers; and combinations thereof.
In an embodiment of the invention, the polymer particles include thermoplastic homopolymers or copolymers selected from homopolymers derived from vinyl aromatic monomers including styrene, isopropylstyrene, alpha-methylstyrene, nuclear methylstyrenes, chlorostyrene, tert-butylstyrene, and the like, as well as copolymers prepared by the copolymerization of at least one vinyl aromatic monomer as described above with one or more other monomers, non-limiting examples being divinylbenzene, conjugated dienes (non-limiting examples being butadiene, isoprene, 1,3- and 2,4-hexadiene), alkyl methacrylates, alkyl acrylates, acrylonitrile, and maleic anhydride, wherein the vinyl aromatic monomer is present in at least 50% by weight of the copolymer. In an embodiment of the invention, styrenic polymers are used, particularly polystyrene. However, other suitable polymers can be used, such as polyolefins (e.g. polyethylene, polypropylene), polycarbonates, polyphenylene oxides, and mixtures thereof.
In a particular embodiment of the invention, the polymer particles are expandable-polystyrene (EPS) particles. These particles can be in the form of beads, granules, or other particles.
In the present invention, particles polymerized in a suspension process, which are essentially spherical resin beads, are useful as polymer particles or for making expanded polymer particles. However, polymers derived from solution and bulk polymerization techniques that are extruded and cut into particle sized resin bead sections can also be used.
In an embodiment of the invention, resin beads (unexpanded) containing any of the polymers or polymer compositions described herein have a particle size of at least 0.2 mm, in some situations at least 0.33 mm, in some cases at least 0.35 mm, in other cases at least 0.4 mm, in some instances at least 0.45 mm and in other instances at least 0.5 mm. Also, the resin beads can have a particle size of up to 3 mm, in some instances up to 2 mm, in other instances up to 2.5 mm, in some cases up to 2.25 mm, in other cases up to 2 mm, in some situations up to 1.5 mm and in other situations up to 1 mm. In this embodiment, the physical properties of LWC walls made according to the invention have inconsistent or undesirable physical properties when resin beads having particle sizes outside of the above described ranges are used to make the expanded polymer particles. The resin beads used in this embodiment can be any value or can range between any of the values recited above.
The expandable thermoplastic particles, or resin beads can optionally be impregnated using any conventional method with a suitable blowing agent. As a non-limiting example, the impregnation can be achieved by adding the blowing agent to the aqueous suspension during the polymerization of the polymer, or alternatively by re-suspending the polymer particles in an aqueous medium and then incorporating the blowing agent as taught in U.S. Pat. No. 2,983,692. Any gaseous material or material which will produce gases on heating can be used as the blowing agent. Conventional blowing agents include aliphatic hydrocarbons containing 4 to 6 carbon atoms in the molecule, such as butanes, pentanes, hexanes, and the halogenated hydrocarbons, e.g. CFC's and HCFC'S, which boil at a temperature below the softening point of the polymer chosen. Mixtures of these aliphatic hydrocarbon blowing agents can also be used.
Alternatively, water can be blended with these aliphatic hydrocarbons blowing agents or water can be used as the sole blowing agent as taught in U.S. Pat. Nos. 6,127,439; 6,160,027; and 6,242,540 in these patents, water-retaining agents are used. The weight percentage of water for use as the blowing agent can range from 1 to 20%. The texts of U.S. Pat. Nos. 6,127,439, 6,160,027 and 6,242,540 are incorporated herein by reference.
The impregnated polymer particles or resin beads are optionally expanded to a bulk density of at least 1.75 lb/ft3 (0.028 g/cc), in some circumstances at least 2 lb/ft3 (0.032 g/cc) in other circumstances at least 3 lb/ft3 (0.048 g/cc) and in particular circumstances at least 3.25 lb/ft3 (0.052 g/cc) or 3.5 lb/ft3 (0.056 g/cc). When non-expanded resin beads are used higher bulk density beads can be used. As such, the bulk density can be as high as 40 lb/ft3 (0.64 g/cc). In other situations, the polymer particles are at least partially expanded and the bulk density can be up to 35 lb/ft3 (0.56 g/cc), in some cases up to 30 lb/ft3 (0.48 g/cc), in other cases up to 25 lb/ft3 (0.4 g/cc), in some instances up to 20 lb/ft3 (0.32 g/cc), in other instances up to 15 lb/ft3 (0.24 g/cc) and in certain circumstances up to 10 lb/ft3 (0.16 g/cc). The bulk density of the polymer particles can be any value or range between any of the values recited above. The bulk density of the polymer particles, resin beads and/or prepuff particles is determined by weighing a known volume of polymer particles, beads and/or prepuff particles (aged 24 hours at ambient conditions).
The expansion step is conventionally carried out by heating the impregnated beads via any conventional heating medium, such as steam, hot air, hot water, or radiant heat. One generally accepted method for accomplishing the pre-expansion of impregnated thermoplastic particles is taught in U.S. Pat. No. 3,023,175.
The impregnated polymer particles can be foamed cellular polymer particles as taught in U.S. patent application Ser. No. 10/021,716, the teachings of which are incorporated herein by reference. The foamed cellular particles can be polystyrene that are expanded and contain a volatile blowing agent at a level of less than 14 wt %, in some situations less than 8 wt %, in some cases ranging from about 2 wt % to about 7 wt %, and in other cases ranging from about 2.5 wt % to about 6.5 wt % based on the weight of the polymer.
An interpolymer of a polyolefin and in situ polymerized vinyl aromatic monomers that can be included in the expanded thermoplastic resin or polymer particles according to the invention is disclosed in U.S. Pat. Nos. 4,303,756 and 4,303,757 and U.S. Application Publication 2004/0152795, the relevant portions of which are herein incorporated by reference.
The polymer particles can include customary ingredients and additives, such as flame retardants, pigments, dyes, colorants, plasticizers, mold release agents, stabilizers, ultraviolet light absorbers, mold prevention agents, antioxidants, rodenticides, insect repellents, and so on. Typical pigments include, without limitation, inorganic pigments such as carbon black, graphite, expandable graphite, zinc oxide, titanium dioxide, and iron oxide, as well as organic pigments such as quinacridone reds and violets and copper phthalocyanine blues and greens.
In a particular embodiment of the invention the pigment is carbon black, a non-limiting example of such a material being EPS SILVER®, available from NOVA Chemicals Inc.
In another particular embodiment of the invention the pigment is graphite, a non-limiting example of such a material being NEOPOR®, available from BASF Aktiengesellschaft Corp., Ludwigshafen am Rhein, Germany.
When materials such as carbon black and/or graphite are included in the polymer particles, improved insulating properties, as exemplified by higher R values for materials containing carbon black or graphite (as determined using ASTM-C518), are provided. As such, the R value of the expanded polymer particles containing carbon black and/or graphite or materials made from such polymer particles are at least 5% higher than observed for particles or resulting walls that do not contain carbon black and/or graphite.
The expanded polymers can have an average particle size of at least 0.2, in some circumstances at least 0.3, in other circumstances at least 0.5, in some cases at least 0.75, in other cases at least 0.9 and in some instances at least 1 mm and can be up to 8, in some circumstances up to 6, in other circumstances up to 5, in some cases up to 4, in other cases up to 3, and in some instances up to 2.5 mm. When the size of the expanded polymer particles is too small or too large, the physical properties of LWC walls made using the present LWC composition can be undesirable. The average particle size of the expanded polymer particles can be any value and can range between any of the values recited above. The average particle size of the expanded polymer particles can be determined using laser diffraction techniques or by screening according to mesh size using mechanical separation methods well known in the art.
In an embodiment of the invention, the polymer particles or expanded polymer particles have a minimum average cell wall thickness, which helps to provide desirable physical properties to LWC walls made using the present LWC composition. The average cell wall thickness and inner cellular dimensions can be determined using scanning electron microscopy techniques known in the art. The expanded polymer particles can have an average cell wall thickness of at least 0.15 μm, in some cases at least 0.2 μm and in other cases at least 0.25 μm. Not wishing to be bound to any particular theory, it is believed that a desirable average cell wall thickness results when resin beads having the above-described dimensions are expanded to the above-described densities.
In an embodiment of the invention, the polymer beads are optionally expanded to form the expanded polymer particles such that a desirable cell wall thickness as described above is achieved. Though many variables can impact the wall thickness, it is desirable, in this embodiment, to limit the expansion of the polymer bead so as to achieve a desired wall thickness and resulting expanded polymer particle strength. Optimizing processing steps and blowing agents can expand the polymer beads to a minimum of 1.75 lb/ft3 (0.028 g/cc) This property of the expanded polymer bulk density, can be described by pcf (lb/ft3) or by an expansion factor (cc/g).
As used herein, the term “expansion factor” refers to the volume a given weight of expanded polymer bead occupies, typically expressed as cc/g.
In order to provide expanded polymer particles with desirable cell wall thickness and strength, the expanded polymer particles are not expanded to their maximum expansion factor; as such an extreme expansion yields particles with undesirably thin cell walls and insufficient strength. Further, the polymer beads can be expanded at least 5%, in some cases at least 10%, and in other cases at least 15% of their maximum expansion factor. However, so as not to cause the cell wall thickness to be too thin, the polymer beads are expanded up to 80%, in some cases up to 75%, in other cases up to 70%, in some instances up to 65%, in other instances up to 60%, in some circumstances up to 55%, and in other circumstances up to 50% of their maximum expansion factor. The polymer beads can be expanded to any degree indicated above or the expansion can range between any of the values recited above. Typically, the polymer beads or prepuff beads do not further expand when formulated into the present concrete compositions and do not further expand while the concrete compositions set, cure and/or harden.
The prepuff or expanded polymer particles typically have a cellular structure or honeycomb interior portion and a generally smooth continuous polymeric surface as an outer surface, i.e., a substantially continuous outer layer. The smooth continuous surface can be observed using scanning electron microscope (SEM) techniques at 1000× magnification. SEM observations do not indicate the presence of holes in the outer surface of the prepuff or expanded polymer particles. Cutting sections of the prepuff or expanded polymer particles and taking SEM observations reveals the generally honeycomb structure of the interior of the prepuff or expanded polymer particles.
The polymer particles or expanded polymer particles can have any cross-sectional shape that allows for providing desirable physical properties in LWC walls. In an embodiment of the invention, the expanded polymer particles have a circular, oval or elliptical cross-section shape. In embodiments of the invention, the prepuff or expanded polymer particles have an aspect ratio of 1, in some cases at least 1 and the aspect ratio can be up to 3, in some cases up to 2 and in other cases up to 1.5. The aspect ratio of the prepuff or expanded polymer particles can be any value or range between any of the values recited above.
In particular embodiments of the invention, the light-weight concrete includes from 10 to 90 volume percent of a cement composition, from 10 to 90 volume percent of particles having an average particle diameter of from 0.2 mm to 8 mm, a bulk density of from 0.028 g/cc to 0.64 g/cc, an aspect ratio of from 1 to 3, and from 10 to 50 volume percent of sand and/or other fine aggregate, where the sum of components used does not exceed 100 volume percent.
Light-weight concrete compositions that are particularly useful in the present invention include those disclosed in co-pending U.S. application Ser. No. 11/387,198, the relevant portions of the disclosure are incorporated herein by reference.
The concrete wall forming system provided in the present invention is less likely to deform and/or fracture due to lateral concrete pressure when used as compared to prior art insulated concrete forms. In the present wall forming system stress concentrations are reduced by providing internal column form surfaces designed such that the lateral pressure from concrete is as evenly distributed as possible. In prior art all-foam ICFs, the internal surfaces have edges that lead to stress concentrations at the corners. By eliminating the stress concentrations in the present wall forming system, the pressure at which deformation and/or failure occurs is increased, reducing the likelihood of deformation and/or failure of the wall forming system. Ultimately, this allows the wall forming system to be made from lower density foam (for the same performance as a higher density foam with another design) or, at the same density, the present wall forming system can be used for greater concrete pour heights.
When lightweight concrete is used in conjunction with the present wall forming system, the density of the mold units can be decreased further or, even greater concrete pour heights can be used at the same mold unit density.
The present invention has been described with reference to specific details of particular embodiments thereof. It is not intended that such details be regarded as limitations upon the scope of the invention except insofar as and to the extent that they are included in the accompanying claims.
