US20090308010A1 - Structural element - Google Patents

Abstract

A structural element is disclosed that is shaped as at least one of a plank, a post, and a board. The structural element comprises a fiber reinforced ceramic cement body having at least an outer layer having a hardness and ductility suitable for receiving and holding a nail. Also disclosed is a structural element having a body at least partially shaped as at least one of a plank, a post, and a board. The body comprises at least an internal layer comprising fiber reinforced ceramic cement, and at least an external layer comprising a material suitable for receiving and holding a nail.

Description

TECHNICAL FIELD
• This document relates to structural elements, including structural elements shaped as at least one of a plank, post and a board.
BACKGROUND
• Wooden posts are susceptible to rotting, insect infestation, fire damage, and may leach hazardous treating chemicals into the environment. In addition, the strength of wood as a structural element is limited, and wood may fray or crack under heavy loads. Further, wood structural elements generally have a short lifetime after which they must be replaced in order to maintain structural stability.
• Ceramic structural elements are typically brittle and tend to crack or break when a sufficient force is imparted unto them.
SUMMARY
• A structural element is disclosed that is shaped as at least one of a plank, a post, and a board. The structural element comprises a fiber reinforced ceramic cement body having at least an outer layer having a hardness and ductility suitable for receiving and holding a nail.
• In some embodiments, the fiber reinforced ceramic cement body comprises magnesium oxide and a binder. In further embodiments, the binder comprises magnesium chloride.
• In some embodiments, at least the outer layer of the fiber reinforced ceramic cement body comprises a filler.
• Also disclosed is a structural element having a body at least partially shaped as at least one of a plank, a post, and a board. The body comprises at least an internal layer comprising fiber reinforced ceramic cement, and at least an external layer comprising a material suitable for receiving and holding a nail.
• In some embodiments, the external layer comprises ceramic cement.
• In some embodiments, the external layer has a hardness and ductility suitable for receiving and holding a nail.
• In some embodiments, the fiber reinforced ceramic cement comprises magnesium oxide and a binder. In further embodiments, the binder comprises magnesium chloride.
• In some embodiments, the external layer comprises ceramic cement and a filler.
• These and other aspects of the device are set out in the claims, which are incorporated here by reference.
• In some embodiments, the structural elements disclosed herein may be wood mimicking structures, which are longer-lasting, stronger, and cheaper than traditional wood products.
BRIEF DESCRIPTION OF THE FIGURES
• Embodiments will now be described with reference to the figures, in which like reference characters denote like elements, by way of example, and in which:
• FIG. 1 is a top plan section view of a structural element.
• FIG. 2 is a top plan section view of a structural element with numerous tubular layers.
• FIG. 3 is a top plan section view of a structural element that has a fiber-reinforced ceramic cement body.
• FIG. 4 is a side elevation view, in section, of a mould for a structural element.
• FIG. 5 is a perspective view of a structural element shaped as a square post.
• FIG. 6 is a perspective view of a structural element shaped as a plank.
• FIG. 7 is a perspective view of a structural element shaped as a round post.
• FIG. 8 is a perspective view of a structural element shaped as a board.
DETAILED DESCRIPTION
• Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims.
• Many structures employ structural elements made of wood, plastic, and metal, among other types of materials, in order to maintain shape and support weight and structure. Wood structural elements are typically cheap, and easy to obtain, but have limited strength and weather resistance. In addition, wood structural elements may be susceptible to infestations by insects, which may also weaken and destroy the structural element over time. Wood may be chemically treated to resist insects and weather, but, as these types of chemical treatment are often applied in the form of hazardous chemicals, such structural elements may pose an environmental hazard. However, wood has a pleasant aesthetic appeal. Plastic structural elements are less prone to environmental or insect degradation, but are far more expensive than wood, and often appear very different from wood aesthetically. Metal structural elements, such as steel structural elements, are extremely strong and durable, but are typically prohibitively more expensive than wood structural elements. Despite the high cost, in some instances steel structural elements may be required, as a wood structural element may not have the structural load capacity required to accomplish the desired goal. Further, steel structural elements may be susceptible to rusting, and may also have to be chemically treated in order to withstand various weather conditions. Steel structural elements by themselves may not have a pleasant aesthetic appeal, and may need to be painted or covered in order to appeal to the eye.
• Structural elements will often form the backbone of a structure, such as by inclusion in the frame of a house, for example. In other cases, structural elements may stand alone, such as in the case of fence posts, where individual structural elements cooperate to define a fence surrounding a desired area.
• Referring toFIG. 1, astructural element10 is illustrated. Referring toFIGS. 5-8,structural element10 may be shaped as at least one of a plank (shown inFIG. 6), a post (shown inFIGS. 5 and 7), and a board (shown inFIG. 8). Referring toFIG. 1, in some embodiments,structural element10 may have abody12.Body12 may be at least partially shaped as at least one of a plank, a post, and a board.Body12 may be, for example, cylindrical. Referring toFIG. 1,body12 may be a fiber reinforcedceramic cement body13, for example. Inaddition body13 may be cylindrical.Body13 may have at least anouter layer14 having a hardness and ductility suitable for receiving and holding a nail. Referring toFIG. 2, for example,outer layer14 may be, for example, an external part ofbody13. In some embodiments,outer layer14 is prepared so that it will absorb the force of a nail without fracturing.
• Referring toFIG. 1, fiber reinforcedceramic cement body13 may comprise magnesium oxide and a binder. The binder may be, for example, binder cement. In some embodiments, the binder comprises magnesium chloride. At least theouter layer14 of the fiber reinforcedceramic cement body13 may comprise a filler, for example. The filler may comprise at least one of sawdust, straw, wood fiber, and particulate matter, for example. In some embodiments, theouter layer14 comprises less than or equal to 30% by weight of filler. In some embodiments,outer layer14 comprises between 10 and 30% by weight of filler. The filler may further comprise a fine powder between, for example, 120 and 270 mesh. In some embodiments,outer layer14 is water resistant. The amount of filler used inouter layer14 may determine the water resistance ofouter layer14. In other embodiments, the amount of filler is used to control or modify the hardness of theouter layer14. In some embodiments, filler may be used to soften or modify the composition throughout the entirestructural element10. In some embodiments, the filler may make the ceramic cement as soft, or sufficiently as soft as, natural wood. This way,structural element10 may provide a cheaper alternative to wood that can be used in all of the same applications as wood.
• Structural element10 may further comprise acore20. Referring toFIG. 2,core20 may be, for example, a hollow core. The hollow core may be formed within a tube ofmaterial22, for example a PVC pipe, or a paper tube. Referring toFIG. 3,core20 may comprise at least one of ceramic cement, wood, plant material, bamboo, paper, and plastic fragments, for example. In other embodiments,core20 may comprise particulates.
• Referring toFIG. 1, in some embodiments,body12 may have at least aninternal layer16 comprising fiber reinforced ceramic cement. The fiber reinforced ceramic cement may comprise magnesium oxide and a binder, for example. The binder may comprise magnesium chloride, for example. Fiber reinforcedbody13 may further comprise at least a fiber reinforcedlayer24 and aceramic cement layer26. Referring toFIG. 2, layers24 and26 may surroundcore20 if present. In some embodiments, the at least aninternal layer16 may comprise at least fiber reinforcedlayer24 andceramic cement layer26, as illustrated, for example. The at least aninternal layer16 may comprise at least one of fiberglass and hemp, for example. Referring toFIG. 1, the fiber reinforcedceramic cement body13 may comprise at least one of fiberglass and hemp. In further embodiments, fiber reinforcedlayer24 may comprise at least one of fiberglass or hemp, for example. In some embodiments, at least one of fiber reinforcedbody13 andinternal layer16 may comprise mesh, such as steel of fabric mesh, for example. The fiber reinforcedlayer24 may have fibers oriented in a direction along the length of thestructural element10, for example. Referring toFIG. 2, fiber within the fiber re-inforcedceramic cement body13 may be formed in one or more tubular layers, such as layers24. In embodiments withinternal layer16, fiber within the at least aninternal layer16 may be formed in one or more tubular layers, such as layers24. Fiber may refer to any type of fiber used to reinforce the ceramic cement, for example. Tubular, in this document, may refer to circular, elliptical, or curved layers, for example. It should be understood that the layers may not be tubular in some cases, for example in the case wherestructural element10 is formed with a non-circular cross-section, for example a square or rectangular cross-section. In some embodiments of astructural element10 with a non-circular cross-section,structural element10 may have, for example, tubular or rectangular internal layers. In other embodiments of astructural element10 with a non-circular cross-section,structural element10 may have, for example, layers with cross-sections that correspond to the cross-section ofstructural element10. For example, a hexagonally cross-sectionedstructural element10 may have layers that have hexagonal cross-sections or other geometrically-shaped cross-sections.
• As illustrated inFIG. 1, fiber reinforcedlayer24 andceramic cement layer26 may be distinctly defined. Referring toFIG. 2, embodiments are possible with a plurality oflayers24 and26. A plurality oflayers24 may be used to increase at least one of the tensile strength, impact resistance, flexural strength, and compression ratio strength of thestructural element10. Each oflayers24 and26 may be composed of plural layers.Layers24 and26 may alternate, as illustrated, or, in some embodiments, multiples oflayers24 or multiples oflayers26 may be placed side by side. Ceramic cement layers26 may have different compositions from one another, in order to impart various properties tostructural element10. Referring toFIG. 3, in some embodiments, fiber reinforcedlayer24 may be positioned external tobody12.
• Referring toFIG. 1, in embodiments whereinternal layer16 is present,body12 may also have at least anexternal layer18 comprising a material suitable for receiving and holding a nail. Referring toFIG. 2,external layer18 may be, for example,outer layer14. Additional layers may be present, for example, in betweenlayers16 and18, betweenlayers24 and26, and/or betweencore20 andinternal layer16. The additional layers are not required to comprise fiber reinforcing or ceramic cement, for example. Referring toFIG. 1,external layer18 may comprise ceramic cement.External layer18 may have a hardness and ductility suitable for receiving and holding a nail. In some embodiments,external layer18 comprises ceramic cement. In further embodiments, at leastexternal layer18 comprises a filler, for example. The filler may have all the same characteristics as the filler of theouter layer14, for example. For example, the filler may comprise at least one of sawdust, straw, wood fiber, and particulate matter. In addition, the ceramic cement comprises less than or equal to 30% by weight of filler. Further, the filler may comprise a fine powder between 120 and 270 mesh. Theexternal layer18 may be water resistant. The water resistance may be imparted by the inclusion of the filler, for example. In other embodiments, the amount of filler is used to control or modify the hardness of theexternal layer18.
• In some embodiments,outer layer14 may comprise at least one pigment. In some embodiments, theexternal layer18 may comprise at least one pigment. The at least one pigment may be, for example, ferric oxide pigments. Various pigments may be used, in order to givestructural element10 different colors, such as dark brown, natural, and red for example. Referring toFIG. 2, the pigment may impart a desired color tostructural element10, in order to add aesthetic appeal. In some embodiments, the at least one pigment or pigments may be chosen to givestructural element10 the appearance of any of a variety of wood types.Outer layer14, if external, may also be textured to add to this effect. In this way,structural element10 may mimic the appearance of wood. In addition,structural element10 may be textured to mimic the appearance of other materials, such as steel.
• Referring toFIG. 1,structural element10 may further comprise aprotective overlayer28 comprising, for example, at least one of plastic, rubber, hemp, and fiberglass.Protective overlayer28 may be positioned, for example, overouter layer14. Referring toFIG. 1, in some embodimentsprotective overlayer28 isexternal layer18. However, in other embodiments,external layer18 may be, for example, positioned beneathprotective overlayer28. In some embodiments,protective overlayer28 may impart UV protection to the materials comprisingstructural element10. In other embodiments,protective overlayer28 may simply be a thin physical barrier to impart further protection tostructural element10 from damage. In some embodiments,protective overlayer28 may impart the water resistance of, or water resistance in addition to the water resistance of, at least one of theexternal layer18 and theouter layer14.
• The desiredstructural element10 made may be, for example, a 3″×8′ round post (illustrated inFIG. 7), a 4″×4″×8′ square post (illustrated inFIG. 5), a 3″×8′ round hollow post (illustrated inFIG. 2), a 1.5″×5.5″×8′ or 0.75″×5.5″×8′ plank (illustrated inFIG. 6), or a 1.5″×8′×8′ board (illustrated inFIG. 8). The dimensions of the exemplarystructural elements10 shown in the Figures are not to scale and are not intended to be limiting.
• Referring toFIG. 1, an exemplary procedure for constructing a post is disclosed. In order to make the ceramic cement, MgCl is dissolved into water at a ratio of, for example, 100 kg of MgCl to 85 kg of water. In some embodiments, 0.5-1.2 kg of MgCl may be mixed with every 1.0 kg of water. In some embodiments, MgCl-6H2O may be used in place of, or in combination with, MgCl. During the dissolution, the temperature may be maintained, for example, between 20 and 30 C. MgO is then mixed with the dissolved MgCl at a ratio of, for example, 1.2 kg of MgO to 1.0 kg of MgCl. In some embodiments, 0.5-1.2 kg of MgO may be mixed with every 1.0 kg of MgCl.
• The mixture of MgO, MgCl, and water may then be split up to make the various compositions of the, as desired, layers14,16,18,24,26, and28, andcore20, that may contain ceramic cement. Each layer instructural element10 may have a different composition, such as for example a different percentage of filler, or a different type of ceramic cement. In other embodiments, the mixture may be used to make one composition that is used for each layer instructural element10. Either way, if filler is required, filler is added to at least a portion of the mixture as desired. The filler may be, for example, ground fiber such as sawdust, straw, or wood fiber. As mentioned above, the filler may be ground into fine powder between 120-270 US standard mesh, for example. The amount of filler added to the mixture may be varied in order to achieve the desired level of hardness. In some embodiments, the filler will effectively soften the ceramic cement, making it more ductile in order to receive and hold a nail or staple, for example. In general, for some types of filler, if the percentage of filler exceeds 30%, the water resistance of the resulting ceramic cement may be negatively affected, and the material may not be stable.
• The at least one pigment may be added to the mixture that will make up theexternal layer18 and/orouter layer14. However, the pH level may need to be approximately 7, or adjusted to approximately 7.
• Referring toFIG. 4, the correct materials that will make upstructural element10, such as forexample core20,internal layer16,outer layer14, andexternal layer18 for example, may be properly positioned and layered within acavity30 defined by amould32.Cavity30 may have the size and shape of the desiredstructural element10.Mould32 may be, for example, made from wood, metal, steel, or aluminum. Referring toFIG. 1, an exemplary layout of the positioning of the layers is illustrated.Mould32 may comprise, for example, twocomplementary halves34. Once thehalves34 are filled, thehalves34 may be closed tightly, and any excess material is squeezed out. Thecavity30 may be textured on the inside, in order to impart a desired textured appearance tostructural element10. Thestructural element10 is then allowed to dry, and then removed frommould32. In some embodiments,structural element10 may be allowed to dry under heat, for example in a kiln. Thestructural element10 may be kept inside themould32 until it is set, and has formed the required shape. The amount of time thatstructural element10 may be required to remain inmould32 may be determined based upon at least one of the ambient temperature, pressure, and humidity. In some embodiments, thestructural element10 may remain insidemould32 overnight. Once removed frommould32, the newly formedstructural element10 may be stored in a temperature and moisture control room at, for example, a temperature of 23 C or greater and 65% humidity until totally dried.Structural element10 may require, for example, 8 or more hours of drying time outside ofmould32.
• Thecore20, if made by ceramic cement, may be moulded in a fashion similar to the above described procedure prior to making thestructural element10.
• Test Results
• Flexural Testing. ASTM D195-05a modified. 3.0 mm/minute crosshead speed. Tests performed using a third point loading rectangular beam (modified) edge apparatus over a 1219 mm span. Test performed on round posts as received but calculations performed assuming rectangular dimension (using post diameter). Posts tested at full diameter as received. For round posts with two and sixlayers24, the posts showed an average modulus of elongation of 3.77 and 8.34 GPa, respectively. Modulus of elongation refers to the deflection (amount of bend) for a given unit of load per area of material. For round posts with two and sixlayers24, the posts showed an average modulus of rupture of 16.1 and 39.6 MPa, respectively. Modulus of rupture refers to the break strength of the material per unit area. The test method and equipment used was designed for evaluation of rectangular materials. Since the posts were in a round configuration, the reported strength values will have some degree of error since the modulus values are calculated using rectangular dimensions (with the diameter of the post being the width and depth of material). The results reported should still be valid for comparison of different post materials tested using the same sample configuration
• Impact Testing. ASTM D6110-06 modified. Specimens cut approximately 13 mm×13 mm×125 mm long along the length of post. Test specimens cut from an area from ¼″ to ¾″ below the outer surface of the posts so as to allow segments of both mineral layers (of different composition) to be contained in the test specimens. No post core material was contained in the test specimens. No notching of specimens. 16 foot/pound pendulum and 100 mm span used for testing. For round posts with two and sixlayers24, the posts showed an average impact resistance of 26±16.0 and 34.3±12.8 kJ/m², respectively. Average impact resistance refers to the amount of energy required to break a given area of test material.
• Tensile Testing. ASTM D638-03. 5.0 mm/minute crosshead speed. Test specimens cut from an area from ¼″ to ¾″ below the outer surface of the posts so as to allow segments of both mineral layers (of different composition) to be contained in the test specimens. No post core material was contained in the test specimens. For round posts with two and sixlayers24, the posts showed an average modulus of elongation of 7.0 and 15.8 GPa, respectively. Modulus of elongation refers to the deflection (amount of stretch) for a given unit of load per area of material. For round posts with two and sixlayers24, the posts showed an average maximum stress (break strength) of 11.3 and 88.5 MPa, respectively.
• Compression Ratio. Astructural element10, shaped as a hollow post (illustrated inFIG. 7) with 14 layers, tested for compression ratio exceeded 350 kg at the mid-point of the post, with a deflection angle of less than 1″. This result demonstrates thatstructural element10 is stronger than average wood (for example spruce) posts.
• Ceramic cement may refer to any type of ceramic material that is suitable for use in thestructural elements10 disclosed herein. Examples include structural, refractory, technical, earthenware, whiteware, porcelain, bone china, stoneware, clay-based, alumina or zirconia oxides, carbides, borides, nitrides, silicides, pottery, and glass-based ceramics. In further embodiments, ceramic cement refers to MgO-based ceramics, such as in the example disclosed herein.
• At least one ofexternal layer18 andouter layer14 may require a thickness suitable to receive a nail, in the event that the drive of a nail may fracture internal layers of more brittle material instructural element10.
• Thestructural element10 disclosed herein is environmentally friendly, rot resistant, insect resistant, fire resistant, aesthetically appealing, and lasts far longer than traditional wood structural elements.Structural element10 may be used like wood, allowing a user to nail, staple, cut and/orpound element10 into the ground, for example.Structural elements10 may be used in, for example, vineyards, homes and gardens, fences, and in commercial, industrial, and residential settings.Structural elements10 may be made from natural earth mineral and fiber, and contain no toxic chemicals required for the preservation of the product. In addition,structural element10 may not require painting, as the appearance ofstructural element10 may be complete upon removal from the mould32 (shown inFIG. 4).
• In the claims, the word “comprising” is used in its inclusive sense and does not exclude other elements being present. The indefinite article “a” before a claim feature does not exclude more than one of the feature being present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims.

Claims (38)

1. A structural element shaped as at least one of a plank, a post, and a board, comprising:

a fiber reinforced ceramic cement body having at least an outer layer having a hardness and ductility suitable for receiving and holding a nail.

2. The structural element ofclaim 1 in which the fiber reinforced ceramic cement body comprises magnesium oxide and a binder.

3. The structural element ofclaim 2 in which the binder comprises magnesium chloride.

4. The structural element ofclaim 1 in which at least the outer layer of the fiber reinforced ceramic cement body comprises a filler.

5. The structural material ofclaim 3 in which the filler comprises at least one of sawdust, straw, wood fiber, and particulate matter.

6. The structural material ofclaim 4 in which at least the outer layer comprises less than or equal to 30% by weight of filler.

7. The structural material ofclaim 4 in which the filler comprises a fine powder between 120 and 270 mesh.

8. The structural element ofclaim 1 in which the outer layer is water resistant.

9. The structural element ofclaim 1, further comprising a core.

10. The structural element ofclaim 9 in which the core is a hollow core.

11. The structural element ofclaim 10 in which the hollow core is formed within a tube of material.

12. The structural element ofclaim 9 in which the core comprises at least one of ceramic cement, wood, plant material, bamboo, paper, plastic fragments, and particulates.

13. The structural element ofclaim 1 in which the fiber reinforced ceramic cement body further comprises at least a fiber reinforced layer and a ceramic cement layer.

14. The structural element ofclaim 1 in which the fiber reinforced ceramic cement body comprises at least one of fiberglass and hemp.

15. The structural element ofclaim 1 in which the outer layer comprises at least one pigment.

16. The structural element ofclaim 1 further comprising a protective overlayer comprising at least one of plastic, rubber, hemp, and fiberglass.

17. The structural element ofclaim 1 in which the fiber reinforced ceramic cement body is cylindrical.

18. The structural element ofclaim 17 in which fiber within the fiber re-inforced ceramic cement body is formed in one or more tubular layers.

19. A structural element having a body at least partially shaped as at least one of a plank, a post, and a board, the body comprising:

at least an internal layer comprising fiber reinforced ceramic cement; and

at least an external layer comprising a material suitable for receiving and holding a nail.

20. The structural element ofclaim 19 in which the external layer comprises ceramic cement.

21. The structural element ofclaim 20 in which at least the external layer comprises a filler.

22. The structural material ofclaim 21 in which the filler comprises at least one of sawdust, straw, wood fiber, and particulate matter.

23. The structural material ofclaim 21 in which at least the ceramic cement comprises less than or equal to 30% by weight of filler.

24. The structural material ofclaim 21 in which the filler comprises a fine powder between 120 and 270 mesh.

25. The structural element ofclaim 19 in which the external layer has a hardness and ductility suitable for receiving and holding a nail.

26. The structural element ofclaims 19 in which the fiber reinforced ceramic cement comprises magnesium oxide and a binder.

27. The structural element ofclaim 26 in which the binder comprises magnesium chloride.

28. The structural element ofclaim 19 in which the external layer is water resistant.

29. The structural element ofclaim 19, further comprising a core.

30. The structural element ofclaim 29 in which the core is a hollow core.

31. The structural element ofclaim 30 in which the hollow core is formed within a tube of material.

32. The structural element ofclaim 29 in which the core comprises at least one of ceramic cement, wood, plant material, bamboo, paper, plastic fragments, and particulates

33. The structural element ofclaim 19 in which the internal layer comprises at least a fiber reinforced layer and a ceramic cement layer.

34. The structural element ofclaim 19 in which at least the internal layer comprises at least one of fiberglass and hemp.

35. The structural element ofclaim 19 in which the external layer comprises at least one pigment.

36. The structural element ofclaim 19 in which the external layer further comprises at least one of plastic, rubber, hemp, and fiberglass.

37. The structural element ofclaim 19 in which the body is cylindrical.

38. The structural element ofclaim 17 in which fiber within at least the internal layer is formed in one or more tubular layers.

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