Ultrathin, pre-stressed, concrete component system

The present invention relates to the construction and manufacture of an ultrathin, prestressed, concrete component system for construction of an exterior wall for a Passive House building, or other types of wall for noise barrier or separation of areas within a property, or separation of properties from the general public.

Typical exteriors of buildings consist of a variety of materials, including masonry, concrete, metal, and glass. Reinforced concrete and steel frame or wood frame structures often have cladding systems to protect them from vibrations and climatic conditions. The patent document U.S. Pat. No. 6,711,866 B2 (inventor Brian M. Blount, May 30, 2004) discloses a thin prestressed concrete cladding panel with six steel wire tendons. The panel is described as approximately 1.5 inches thick, and the design includes a bolt-and-screw system embedded within the panel. A wall composed of 1.5-inch-thick panels, each with six steel tendons, requires a large amount of materials. It is not only heavy and expensive but depletes environmental resources. The bolts and screws connect the concrete cladding with the building's interior space and create thermal bridging, which negatively impacts energy efficiency of a building. Construction material costs are high due to the extra thickness of the Blount panel (i.e, 1.5 inches versus 0.5 inch for the panel described herein), as well as the provision of bolts and screws to keep the panel in place in the built environment; installation of the Blount panel (labor costs) is expensive because of the cost to install the many bolts that must be used to secure said panels to a building structure. Maintenance costs for the Blount panel are high (labor costs) because of the freeze-thaw cycle (i.e., loosening of the bolts and screws and the re-tightening of them) at the bolts and screws and other connections between the Blount panel and building exterior.

The invention remedies the aforementioned drawbacks by providing a panel that is ultrathin (0.5 inch) and a component system that is freestanding, without screws, bolts, or brackets. Ultrathin, pre-stressed, concrete component system (UTPSCCS), comprising three-part, prefabricated components, consists of a concrete panel mounted between two concrete columns. Multiple components are assembled to form the exterior wall of a Passive House or other structure as described below. A Passive House is a highly insulated building that achieves at least 80% energy efficiency via airtight construction and a minimal transfer of heat between exterior walls and an interior living space. The UTPSCCS is suitable for Passive House construction because the wall is a free-standing shell that does not touch the interior living space, does not transfer heat, and achieves zero thermal bridging. Special care is taken at the windows (not shown) and doors (not shown) (and other penetrations, not shown) to minimize the de minimis thermal bridging effects there. Triple pane windows can reduce thermal bridging through the glazing, and insulation and airtight construction can reduce thermal bridging at the perimeter of the door and window frames. Part one of the UTPSCCS is a concrete panel that is flat on the face and has a raised grid on the reverse side. The grid pattern provides additional flexural strength without having the panel be thicker everywhere, thereby requiring less concrete material and less weight. Prestressed stainless steel cable is embedded within the concrete panel along each line of the grid. There are two types of panels. Type 1 designates the panel that is placed along the base of the assembled wall, subsequently referred to as the “bottom-most panel.” Type 2 designates the panels that are stacked on top of the Type 1 panels, subsequently referred to as the “stackable panel.” Both types are flat on their faces. Both are 0.5 inches thick with raised grids that protrude from their reverse sides. Both contain 1/16-inch diameter cables embedded within their panels and/or grid elements. The difference between Type 1 and Type 2 panels is the grid pattern. The grid on the bottom-most panel protrudes a consistent 0.5 inch from its reverse surface. On the stackable panel, the majority of the grid pattern protrudes 0.5 inch but there is a wider, thicker horizontal grid bar nearest the base of the panel, which protrudes 1.5 inches. The purpose of the wider, thicker bar in the stackable panel is to provide a ridge for resting on the panel below it. The grid spacings and the thickness of the grid and panels remain consistent no matter the size of the panels. Parts 2 and 3 of the UTPSCCS are mirror-image concrete columns that assist in holding each panel in place. The panels are inserted into cavities in the columns. There are two types of column: Type 1, linear columns that allow panels to be placed along the length of a building; and Type 2, corner columns that are placed at the corners of the building. The linear column has slots (set at 180 degrees from each side) into which panels are stacked vertically. The corner column is configured with slots to hold two sets of stacked panels set at a 90-degree angle to one another. There are no nails, screws, or brackets required to keep the panels in place; panel wall integrity is accomplished by gravity effects. The panels and columns can be sized and cast in the desired dimensions. The spacing of the ½-inch grids is variable, based on the desired flexural panel strength. The panels and columns are then assembled horizontally and vertically and at angles to form walls. The height of the columns and the distance between them may vary depending on the dimensions of the wall and the size of the panels. But the other dimensions of the columns remain the same.

The UTPSCCS has three unique features: a) Concrete panels that are thinner than commercially-available prestressed panels due to the raised grid pattern; b) a panel-in-slot (cavity) design that requires no bolts, no screws, nor any other fastener; and c) a free-standing shell that has no contact with an interior space (except at the minimal points where windows, doors, and utility penetrations are identified), thus drastically limiting heat transfer, i.e., thermal bridging. A detailed description of each figure is provided below. This section concludes with: a) Description of the rubber mold device not shown; b) alternate uses for the UTPSCCS panel; and c) the recipe for the concrete in the UTPSCCS panel (Part 1 of the patent). The recipe for the concrete in the linear and corner columns (Parts 2 and 3 of the patent) is not provided, as the appropriate recipe is not proprietary.

Referring first to, there is therein illustrated a preferred embodiment of the invention comprising an ultrathin, prestressed reinforced concrete paneland, which maybe, for example 144 inches in length, 72 inches in width, and have a ½ inch thickness. This size is only illustrative as the panel may be made of a variety of sizes. An ultrathin panel as used herein refers to a panel with a maximum thickness of approximately ½ inch. The illustrated panelsandare formed with an exposed facefor all panel types, and an opposite back face(for the Part 1, Type 1, bottom-most panel), and(for the Part 1, Type 2, stackable panel) each of which faces are flat and parallel to one another. Alternatively, the exposed facemay be textured rather than flat to achieve a desired architectural appearance on the panel. Panelis shown as formed with a pair of opposite side faces, or edges,,, and a pair of opposite side faces, or edges,,. In the illustrated embodiment the side and faces are at 90-degree angles with each other and are mirror images of each other in shape. Extending through the panelandis a prestressed, parallel tendon, which may comprise a singular, longitudinally extending stainless steel wire rope. This single wire rope extends between the side faces,and side faces,(for panel), and side faces,and side faces,(for panel).

Referring more particularly to, the tendon, spaced a distance d(as measured in a center line with respect to the panel grid feature (on panel face), from the exposed face. The distance dis preferably approximately equal to ⅜ inches and distances dis preferably approximately equal to 0.4 inches from either edge of the,grid features on face, in the case of the ½ inch panel, T. The tendon diameter is preferably 1/16-inch, 7×7 strand stainless steel wire rope. Such rope configuration facilitates formation of a secure bond between the concrete and the rope, and positioning it ⅜ inch from the panel faceassures that the tensioning effect will be present not only in the ½ inch portion of the panelbetween panel edges,, but also in the raised grid elements,of panel, and also along the raised grid elementsandof panelin.andalso illustrate the tendonnear the raised grid elementof panel, and where a set of three tendonsextend along the grid elementbetween the,edges. The three tendons of grid elementare equally spaced at a ddistance from the faceof panel, preferably ¾ inch, and each one separated by d, preferably 11 inch, and from each edge of the grid element. Note that in panelsand, the grid elements,are raised T, preferably 0.5 inch, and Tacross, preferably ¾ inch, while in panel, grid elementis raised T, preferably 1.5 inches, and Tacross, preferably 5 inches, with Tdistance from the bottom of grid elementto the paneledge, preferably 4 inches.

Referring, second, to, there is therein illustrated a preferred embodiment of another feature of the invention comprising a corner columnand a linear column.illustrates column, where top faceA, bottom-up face, face, face, face, and faceare illustrated.also illustrates column, but only the top faceA, with preferred dimensions, including the overall dimensions of Tby T, preferably approximately 29 inches by 13 inches, with a cavity depth (for panelandinsertion) of T, preferably 12½ inch and a cavity width of T, preferably 4 inches. The housing for the panel slot is T, preferably 4½ inches thick, with a slot channel base of T, preferably 3½ inches.illustrates column, where top faceB, bottom-up face, face, face, face, and faceare illustrated.illustrates column, but only the top faceB, with preferred dimensions, including the overall dimensions of Tby T, preferably approximately 32 inches by 13 inches, with a cavity depth (for panelandinsertion) of T, preferably 12½ inch and a cavity width of T, preferably 4 inches. The housing for the panel slot is T, preferably 4½ inches thick, with a slot channel base of T, preferably 3½ inches.

Referring, second, to, there is therein illustrated a preferred embodiment of another feature of the invention comprising columnand column faces,.illustrates column, but only the column face, with locations of column faceB, column face, column face, and column face. The column slot cavity has various dimensions T(with a dimension dependent on the desired height of a constructed wall), T(with a preferred dimension of 13 inches), T(with a preferred dimension of 5½ inches), T(with a preferred dimension of 4½ inches), T(with a preferred dimension of 4½ inches), T(with a preferred dimension of 4 inches), T(with a preferred dimension of 5½ inches), T(with a preferred dimension of 3 inches), T(with a preferred dimension of 5½ inches), T(with a preferred dimension of 2 inches), and T(with a preferred dimension of 6½ inches).also illustrates column, column face, with locations of column faces,,,B. To the right of columnis a panelwith panel edgeand the location of panel edges,and panel faces,. Above panelare two panels. Each one has panel edge, and locations of panel edges,and panel faces,.illustrates two columns, each with three panels stacked within the column cavity. The columnto the left illustrates column face, and the locations of column faces,,,B. Of the stacked panels, the bottom-most is a panel, with a panelresting upon a panelwith a grid element() of panelsitting directly on panel's panel edge. Upon the paneljust mentioned is another panel, stacked in an identical way as discussed above, except, now, the second panel's grid elementrests upon the lower panelpanel edge. Additional panelsmaybe stacked to achieve a desired height of a well with, likewise, extending the height of the columns,to accommodate the extra panel height. Alternatively, the desired wall height may comprise a single paneland appropriately-sized columns,.

Referring, third, to, there is therein illustrated a preferred embodiment of another feature of the invention comprising three columnswith two sets of stacked panelsandresting between two columnsand one set of panels between a columnand a column. Each columnillustrates its panel face, while columnillustrates its column face. As illustrated in, the bottom-most panel in each stack is a paneland each panel above it is a panel.illustrates ten columnsand four columnsin a top view of a panel wall that totally surrounds an interior space. The illustrated top edges of the panelsare panel edges. The illustrated top of columnfaces is column edgeB and the top of columns face for columnsis column edgesA. Note that the illustrated interior space could be a Passive House structure, that has no thermal bridging between its space and the columns,or panels,.

Referring, fourth, to, there is therein illustrated a preferred embodiment of another feature of the invention comprising two columns, a paneland panel. That figure is a photo of constructed panelstacked upon panel, resting between tow columns, within each column's cavity.

Referring, fifth, to, there is therein illustrated a preferred embodiment of the invention, comprising the framing element, tensioning device, and cablethat is used to pre-tension the singular cablethrough a panelor panel. The preferred material of construction for framing elementis wood, size 2″ by 4″ and as long and wide as desired to produce the desired panel size. The exact spacing between the holes illustrated on framing elementfaces,,,are only important as they align to the precise holes of the rubber mold (not shown) into which the concrete mix for paneland panelis poured. The holes of framing elementfaces,,,align with the position of the wire ropeillustrated as described: a) Panelin, panel edges,,,; b) panelin, panel edge; c) panelin, panel edges,,,; and d) panel,, panel edgeand grid element.

Rubber Mold Feature Not illustrated

In both the Blount patent and the application herein, the mold device into which concrete is poured (see concrete recipe for panels,below) are not illustrated. Such a device is typically composed of a rubber material, placed within the framing element(for example) illustrated in, at the appropriate position so that the singular cablebecomes embedded at the depth into the panels,identified inafter the concrete is poured. The prestress force (about 40 pounds of tension) is not released until the concrete is fully cured, after about 48 hours.

The potential uses for the UTPSCCS panel are described below.

There are six considerations important to the preparation and manufacturing of items comprising this invention.

The concrete for the UTPSCCS panel is composed of: a) Portland Pozzolana Cement; b) sand; c) ¼-inch gravel (or similar material, such as recycled glass); d) water; and e) super plasticizer. Note that this recipe includes a melamine plasticizer, also known as polycarboxylate plasticizer, which can reduce the amount of water in the concrete mix by 15% to 20%, and increase the strength of the concrete.

The constituent ratio and weight of each material for the panel,concrete mix are as follows: a) cement 2.4 lb or 1,104 g; b) sand 2.4 lb or 1,104 g; c) ¼-inch gravel 2.4 lb or 1,104 g; d) water 1.0 lb or 441.5 g; and e) super plasticizer 0.002 lb or 0.077 g. Without the cable, this mix weighs 8.2 pounds. But this 8.2 pounds of concrete mix will produce an approximate 2.5 square foot (by 0.5 inch thick) panel,, so the per square foot weight of the cured concrete is approximately 6.6 pounds.

Note: the recipe for the columns,is not provided as it is not proprietary. Only the shape of the columns is proprietary with cavities and cavity protrusions illustrated in.