STRUCTURAL UNIT

Abstract: A lightweight, dimensionally stable structural unit (12) for use as facing on houses and other buildings. The unit comprises a core (10) of foam glass, a layer (11) of fibre-reinforced concrete enclosing the foam glass core (10), and an interconnecting layer (13) of asphalt or silica glue and of wet-strength fibreglass reinforced cardboard or a fibreglass mat, such as a textile cloth of polymer glass fibre.

Description: STRUCTURAL UNIT TECHNICAL FIELD The subject invention concerns a lightweight, dimensionally stable structural unit intended primarily as a facing slab for apartment houses and other buildings. BACKGROUND OF THE INVENTION Structural units intended as facing on houses and other premises must not contain combustible materials. A material that is frequently used is e.g. concrete. External walls made from prefabricated concrete building elements usually must have an external insulation layer and a cavity wall to protect the insulation, in order to meet the heat-insulation standard. A wall of this kind is comparatively expensive to manufacture and time- consuming to produce. As an alternative to the cavity wall construction sheet-metal or slabs of a weather-resistant material may be used. Various modifications of sandwich constructions also exist, comprising insulation, an external facing and an inner cover, which constructions meet the requirements for low weight and dimension stability. Hitherto, sandwich constructions have not, however, been competitive on account of the considerable costs involved. In addition, they have primarily been intended for buildings not exceding a height of five stories. Other factors to consider in the construction and arrangement of building elements or structural units intended as facing for houses and other buildings are, in addition to fire-resistance, durability, weather- resistance, heat insulation properties, weight and manu¬ facturing costs but also the coefficient of expansion, vapour permeability and the ability to dampen the transmission of sound are important factors in this connection. TECHNICAL PROBLEM The purpose of the subject invention is to provide a building element or structural unit intended primarily as facing on apartment houses or office buildings or the like and exhibiting high values in respect of all the factors outlined in the aforegoing, in addition to which, on account of its low weight and high dimension stability, the structural unit may be used in tall buildings and whenever the wall has to meet severe demands with respect to heat, cold and vapour pressure. THE SOLUTION This purpose is achieved in a structural unit in accordance with the invention having a foam glass core enclosed by a layer of fibre-reinforced concrete, a layer arranged to adhere to and to be laminated with said core and said concrete layer being positioned intermediate the foam class core and the fibre-reinforced concrete layer. DESCRIPTION OF THE DRAWING FIGURES The invention will be described in closer detail in the following with reference to the accompanying drawings, wherein Fig. 1 is a plan view of a building element or struc- tural unit in accordance with the invention in the form of a facing slab, Fig. 2 is a sectional view along line II-II of Fig. 1, Fig. 3 is a lateral sectional view through the arrangement for fastening the structural unit in accord¬ ance with the invention to a horizontal concrete beam, Fig. 4 is a view from above of a corner of a facade including the fastening arrangement: of a structural unit in accordance with the invention to a vertical concrete beam, Fig. 5 illustrates the fastening arrangement of the structural unit in accordance to the invention to a cellular concrete floor, and Fig. 6 is a sectional view of a detail showing the structure of the structural unit. DESCRIPTION OF an EMBODIMENT OF THE INVENTION The building element or structural unit according to the invention and illustrated in the drawings is constructed as a facing wall unit and is provided with a core 10 of foamed quartz glass, known as foam glass. This glass is produced by heating melted quartz glass until it becomes liquid, whereupon the liquid glass is allowed to expand, by addition of a gas-generating substance, until the glass forms a fine-cell foam. When the glass has solidified, it forms a rigid block that may be sewn into slabs of suitable thickness. The length and width of the slabs are adjusted to the intended measures of the finished structural unit. Apertures are made in the slab to accommodate various fittings to be used for the mounting of doors and windows in the facing unit, and to lift and mount the unit to the building framework. The fittings, including threaded sleeves and flat bars of e.g. stainless or galvanized steel, are positioned inside the foam glass core. An adhesive layer 13 is then applied on top of the foam glass core 10, and the latter, together with the layer 13, is cast into an enclosing layer 11 of fibre- reinforced concrete which adheres to layer 13. The layer 11 of fibre-reinforced concrete could have a thickness of approximately 15 - 20 mm whereas the foam glass core could have a thickness of 120-200 mm. Fig. 1 illustrates a finished facing unit 12 includ¬ ing a window 27 which by means of a door-frame screw fastener 14 is mounted in a steel frame 15 cast into the unit. A lifting loop 16 is cast into the unit to be used in the handling thereof during transport to the building site and to lift the unit in position on a building framework. Fittings 17 positioned at the upper and lower edges of the unit are used to secure the unit to the building framework. Fig. 2 illustrates the unit 12 in a sectional view. As appears therefrom, horizontally projection portions of the fittings 17 are secured by means of screw fasteners 18 to the floor structure 19, 20 of the building frame. A reinforcement construction 21 of stainless steel interconnects the two layers 11. Figs. 3 - 5 illustrate in closer detail the manner in which units 12 are mounted in a building framework comprising a prefabricated cast cellular concrete floor 22, a horizontal concrete beam 23 and a vertical concrete beam 24. The joints between two units 12 and between the unit and the framework are insulated by means of mineral wool caulking 25 (known as soft sealing). In the corner portion of the building illustrated in Fig. 4, a corner unit 12 is secured by means of threaded sleeves and bolts 26 cast into the unit and extending through the vertical concrete beam 24. Fig. 6 is a detailed sectional view showing the structure of the facing wall unit 12. The centre is formed by the foam glass core 10, surrounded on either side by the adhesive layer 13 and externally thereof and adhering to layer 13, by the fibre-reinforced concrete layer 11 enclosing the foam glass core 10 and forming the outermost layer. Preferably, the adhesive layer 13 consists of an asphalt adhesive or a silicate glue and glass-fibre reinforced and preferably wet-strength cardboard or a glass-fibre cloth, such as a textile cloth of polymer glass fibres. The foam glass core described above preferably consists of pure quartz glass without a binding agent and preferably having a completely closed-cell structure. The dimension stability is unchangeable. The dead weight is about 1.2 kN/m 3 and the density about 105 and 165 kg/m 3 . The material is non-combustible and can withstand temperatures between -260°C and +430°C. The vapour per¬ meability is practically none and the sound transmission value is 28dB for thicknesses of 100 mm and normal frequency ranges. The structural unit as a whole has a compressive strength in the order of 400-1600 kN/cm 2 and a flexural strength of between 300 and 1600 kN/cm 2 . In summary, the structural unit in accordance with the invention exhibits the following properties_ thermal insulating dimensionally stable - diffusion proof impermeable to radon radiation non-combustible resistance to attacks from vermine and to mould- formation - manufactured without hazards to the environment recycable The invention is not limited to the embodiments described in the aforegoing but several modifications are possible within the scope of the appended claims»

Claims: CLAIMS 1. A lightweight, dimensionally stable structural unit, primarily for use as facing on houses and other buildings, said unit having a core (10) of foam glass enclosed by a layer (11) fibre-reinforced concrete, c h a r a c t e r i z e d by an adhesive layer interposed between the foam glass core (10) and the layer (11) of fibre-reinforced concrete to adhere to and to be laminated with said core and said concrete layer. 2. A structural unit as claimed in claim 1, c h a r a c t e r i z e d in that said adhesive layer (13) con¬ sists of an asphalt adhesive applied on said foam glass core (10) and covered with fibreglass-reinforced cardboard, with a fibreglass mat or the like which adheres to the layer of fibre-reinforced concrete. 3. A structural unit as claimed in claim 1, c h a r a c t e r i z e d in that the adhesive layer ( 13) is formed by a silica glue adhesively applied on said foam glass core (10) and covered with fibreglass-reinforced coardboard, with a fibreglass mat or the like which adheres to the layer of fibre-reinforced concrete. 4. A structural unit as claime in any one of the preceding claims, c h a r a c t e r i z e d in that the layers (11) of fibre-reinforced concrete on either side of the foam glass core (10) are anchored to one another by means of forked clamps, a reinforcement construction (21) or the like.

Inventors: NULAND KJELL, SVENNING JOHNNY, NULAND, KJELL, SVENNING, JOHNNY
Applicants: NULAND KJELL, SVENNING JOHNNY, SWESIB RITKONTOR AB
Application year: 1993
Main classification: E04B2
IPC codes: B32B5, E04B1, E04B2, E04C2