AU2002256579B2 - Masonry block constructions with polymeric coating - Google Patents

Description

WO 02/101164 PCT/AU02/00759

I

TITLE:

MASONRY BLOCK CONSTRUCTIONS WITH POLYMERIC COATING FIELD OF THE INVENTION THIS INVENTION is concerned with improvements in masonry block constructions.

BACKGROUND OF THE INVENTION The invention is concerned particularly although not exclusively with reinforced mortarless block constructions.

Hollow structural blocks such as masonry blocks have been successfully employed for many years in the construction of load bearing and non-load bearing walls in commercial buildings, domestic dwellings and other structures such as retaining walls, fences and the like. As used herein, the expression "masonry" block is intended to embrace all manner of structural blocks.

Generally speaking, masonry block walls are constructed on reinforced concrete footings or a concrete floor slab as a base. Such walls include mortared joints.

Depending upon wind loadings for such block walls, rigidity is conferred by the formation of integral reinforced piers wherein starter bars extend into the hollow wall cavity at spaced intervals steel reinforcing bars are inserted into the wall cavities occupied by the starter bars and fluid concrete is then poured into the wall cavities occupied by the steel reinforcing bars to form spaced, steel reinforced piers in the wall structure.

In cyclone rated areas it is necessary to be able to structurally tie a roof structure through steel rods to the footings or floor slab on which WO 02/101164 PCT/AU02/00759 2 the masonry walls are constructed.

While generally satisfactory for their intended purpose, such mortar jointed structural block wall constructions suffer a number of practical disadvantages.

Not only are these prior art block wall construction techniques extremely labour intensive, a high level of skill is required in block laying with mortared joints. Skilled labour is expensive and frequently difficult to obtain when required.

The requirement for starter bars to be accurately located in a supporting base such as footings or a raft slab combined with poured concrete steel reinforced piers at required spaced intervals adds substantially to both labour and material costs, particularly in cyclone rated areas where roof tie down means must be incorporated in the wall.

Although mortarless masonry blocks have been proposed to reduce the level of skilled labour required, these have not found favour in building construction due to reduced structural integrity and increased reinforcing costs as well as poor weather resistance of mortarless joints.

Where it is required to form integral piers, it is usually necessary to hire a concrete pumping vehicle to pump a concrete slurry into the wall cavities at spaced intervals to encapsulate the reinforcing bars. This is expensive and time consuming.

OBJECT OF THE INVENTION It is an aim of the present invention to overcome or ameliorate at least some of the shortcomings associated with prior art structural block IO 3 c wall constructions.

SSUMMARY OF THE INVENTION According to one aspect of the invention there is provided a method for construction of a structural block wall, said method comprising the steps of:n erecting on a base a wall of mortarless structural blocks; and (Ni applying to opposite faces of said wall a fibre reinforced polymeric coating, said method characterized in that said fibre reinforced polymeric coating extends over a portion of said base adjacent opposite faces of said wall to form a bond between said wall and said base whereby said base and said wall form an integral structure.

Preferably, said at least some of a base course of structural blocks are anchored to said base by a polymeric adhesive compound.

If required, the structural blocks may include one or more projections engageable, in use, with complementary one or more recesses in an adjacent structural block.

Suitably, said blocks are self-aligning when stacked.

Most preferably said opposed faces comprise upper and lower faces.

Suitably said fibre reinforced polymeric coating extends over a portion of said base to form a bond between said wall and said base.

WO 02/101164 PCT/AU02/00759 4 Preferably said fibre reinforced polymeric coating extends over portions of said base on opposite sides of said walls.

The fibre reinforced polymeric coating may extend over a top surface of said wall.

If required, mounting brackets may be secured to an upper course of blocks in said wall to permit, in use, connection of a roof structure to said wall.

Suitably, said mounting brackets are secured to respective structural blocks by a polymeric adhesive compound.

If required, reveal surfaces in wall openings may have applied thereto a fibre reinforced polymeric coating.

Preferably, said fibre reinforced polymeric coating includes a layer of fibreglass reinforcing material.

The layer of fibreglass material may comprise a sheet of woven or non-woven fibreglass.

Suitably, said fibreglass reinforcing material is an alkaline resistant grade.

Preferably, said fibre reinforced polymeric coating is formed by applying a base coating of a liquid curable polymeric composition to a wall surface, positioning on said base coating a layer of fibre reinforcing material, applying to an exposed surface of said layer of fibre reinforcing material a further coating of a liquid curable polymeric composition and allowing said liquid curable polymeric composition to cure.

The liquid curable polymeric composition may be applied to a WO 02/101164 PCT/AU02/00759 surface of the wall and/or the exposed surface of said layer of fibre reinforcing material by any suitable means such as spraying, trowelling, squeegee application or the like.

Suitably, said base coating is applied to a substantially even thickness by means of guide projections extending from opposite normally exposed faces of said structural blocks.

Preferably, said guide projections comprise spaced substantially parallel ribs serving, in use, to guide a screeding or trowelling device to apply said base coating to a substantially even thickness.

If required, a decorative coating may be applied over the fibre reinforced polymeric coating.

Suitably, the decorative coating comprises a polymeric mineral finish sealant.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may be more fully understood and put into practical effect, reference will now be made to preferred embodiments illustrated in the accompanying drawings in which:- FIG. 1 shows schematically a perspective view of a structural block suitable for use with the invention; FIG. 2 shows a side elevational view of the block of FIG. 1; FIG. 3 shows a top plan view of the block of FIGS. 1 and 2; FIG. 4 shows an end elevational view of the block of FIGS. 1-3; FIG. 5 shows a cross sectional viewthrough a wall constructed in accordance with the invention; WO 02/101164 PCT/AU02/00759 6 FIG. 6 shows a partial perspective view of a finished wall structure according to the invention; FIG. 7 shows one form of lintel structure; FIG. 8 shows a partial cross-section through a lintel structure; FIG. 9 shows a truss tie-down to a lintel; FIG. 10 shows an alternative lintel configuration; and FIG. 11 shows an alternative block configuration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIGS. 1-4 there is shown a masonry block suitable for building "dry-stacked" or mortarless wall structures.

Masonry block I includes opposed side walls 2, opposed end walls 3 and intermediate webs 4 defining apertures 5a, 5b and 5c extending along upright axes through block 1.

On the upper face of block 1 there are formed projections 6 adapted to locate in complementary recesses 7 formed in an adjacent block.

Recesses 7 are formed in the lower opposite wall portions of apertures and 5c whereby a channel-like recess 8 extends overthe lowerface of block 1 between the lower portions 2a, 2b of opposed side walls 2.

The structure of the block permits quick, accurately aligned stacking of blocks in a conventional manner wherein the blocks of one course overlap the end joints between blocks of an underlying course, the end joints being located centrally of central aperture 5b. Part blocks (not shown) are utilised for wall ends, wall openings and joints between adjacent walls.

WO 02/101164 PCT/AU02/00759 7 FIG. 5 shows a part cross-sectional view of a wall structure according to the invention and illustrates the method of construction according to the invention.

A first or base course of blocks 10 is arranged in a desired configuration on a floor slab 11 and a quantity of a polymer modified cementitious mortar 12 (available underthe trade mark "Quickwall Australia") is poured into the apertures of the blocks to anchor them to the slab 11.

The wall is then completed by dry-stacking the blocks of FIGS.

1-4 to a desired height and length.

A fibre reinforced polymeric coating 13 is formed on both wall surfaces by applying a first or base layer of liquid curable polymeric adhesive (also available under the trade mark "Quickwall Australia") by spraying or trowelling. The base layer extends over regions 14, 15 of the slab 11.

A sheet of alkaline resistant fibreglass mesh of say 100-150 gm m 2 is then applied to the wetted surfaces of the slab and the opposite wall surfaces 16, 17 whereby the fibreglass mesh extends continuously from slab region 14, over outer wall surface 17, over the top of upper block course 18, down the inner wall surface 16 and finally terminating at the outer edge of slab region 15. The fibre reinforced coating 13 is completed by the application of a further or top layer of the same liquid polymeric adhesive.

Successive sheets of fibreglass are overlapped by about 200 mm whereby the finished wall structure comprises dry stacked blocks having an integrally formed high tensile fibre reinforced polymeric skin extending from the floor slab, to which the skin is bonded, up and over the top of the WO 02/101164 PCT/AU02/00759 8 wall, effectively encapsulating the wall.

To maximise the structural integrity and weatherproofing of the joint between the base course and the reinforced wall skin, a corner bead 13a of wetted fibreglass rovings, a fibreglass mesh tape or the like is positioned in the corners between the wall surface and the slab surface so that a radiussed joint is formed.

At spaced intervals, rafter or roof truss brackets 19 are anchored to the wall structure by stuffing a block aperture with, say, newspaper 20 and then pouring in a layer 21 of cementitious mortar of the same type used to bond the base course 10 to slab 11. Bracket 20 is anchored in the layer 21 and protrudes through the top portion 22 of fibre reinforced layer 13.

FIG. 6 shows a part perspective view of a finished wall construction in accordance with the invention.

The wall is constructed generally in accordance with the method steps described in relation to FIG 5 and as such like features employ like reference numerals where appropriate but where wall openings 25 such as a window, door or the like are concerned additional steps are required.

While the wall is erected very quickly by dry-stacking or the like, there are several ways to form a lintel over a door or window opening.

In one method, a steel angle iron can be used as a lintel support and where this is done, the course of blocks forming the lintel beam are initially tied together and to the steel angle iron with a preliminary fibreglass reinforced polymer skin 26. Once encapsulated, the wall WO 02/101164 PCT/AU02/00759 9 construction can then continue as previously described. When forming the polymeric fibre reinforced skin 27 on the wall surfaces, the regions around the window reveals 28 are also coated with the integrally formed skin 27.

In an alternative lintel construction, a plurality of U-shaped blocks are supported on formwork in an end to end configuration. The central channel so formed locates steel reinforcing members and concrete is poured into the cavity to form a bond beam lintel. The outer surfaces of the lintel so formed have a preliminary fibre reinforced polymeric skin formed thereon such that when the final wall structure is coated, the lintel region incorporates a double layer of fibre reinforced polymeric material.

Depending upon the wind loading for the structure, the lintel may comprise two or more courses of mortar filled lintel blocks, with or without steel reinforcing therein.

The inner and outer wall surfaces are then given a decorative and/or protective coating of a polymeric mineral finish (once again available under the trade mark "Quickwall Australia"). This finish includes a generally spherical aggregate having a mean diameter of about 2mm whereby the aggregate particles act as a guide to permit a trowelled coating of substantially even 2mm thickness controlled by the aggregate particles. This permits the use of less skilled labour in the final finishing of thewall surfaces.

FIGS. 7 to 10 illustrates aspects of yet another lintel construction forming part of the system according to the invention.

In FIG. 7, there is shown a block wall structure 30 with a doorway aperture 31. Above doorway aperture 31 is a lintel member 32 in WO 02/101164 PCT/AU02/00759 the form of a steel frame 33 with void forming cores 34 located therein.

FIG. 8 is an enlarged partial cross-sectional view of a top rail portion 33a of lintel 32 as shown in FIG. 7.

Frame 33 comprises a rolled steel U-section channel 33a forming a top rail to the rectangular frame and a like member 33b (shown in FIG. 7) forming a bottom rail. Similar upright channel sections 33c, 33c of slightly narrower width are nested within the outer flanges of top and bottom rails 33a, 33b respectively and are secured thereto by a suitable fastening means such as a self-piercing rivet, a self-tapping screw, welding or the like passing through overlapping channel edge flanges. A similar upright member 33e is located intermediate end members 33c, 33d.

The channel like members 33a, 33b, 33c and 33d are configured with their respective recesses facing inwardly of the frame structure 33 to locate the foam styrene void forming cores 34 therein.

As shown in FIG. 8, the lintel member 32 comprises a pair of frames 33 in side by side juxtaposition with their outer edges flush with the respective opposite faces of adjacent blocks. A top course of blocks extends over the top of lintel member 32.

As with structures previously described with reference to FIG. and FIG. 6, the block wall structure 30 and the lintel member 32 are coated with a glass fibre reinforced polymeric skin 35 which extends over the top of the top course of blocks 30a and under bottom rail 33b to encapsulate the blocks 30a and lintel member 32 where it extends across opening 31 whereby the blocks 30a and the lintel member 32 together function as a WO 02/101164 PCT/AU02/00759 11 truss member. The outer or exposed surfaces of the wall structure and lintel member can also have applied thereto a decorative andlor protective coating 36 of a polymeric mineral finish as previously described and this, when cured, serves to further reinforce that part of the wall structure and the lintel member now functioning as a truss beam.

FIG. 9 shows a method of attachment of a roof truss 37 to the lintel member 32 shown in FIG. 8.

Truss 37 is simply secured to the lintel member 32 by fasteners 38 extending through angle brackets 39 into the truss 37 and the top rail portions 33a of frames 33 forming the lintel member 32. As the frames 33 are subsequently mechanically tied to the wall structure, on which the lintel member rests, by the fibre reinforced polymeric skin, both roof mass and wind loadings are adequately met by this tie-down method.

FIG. 10 shows generally a block wall structure 4a according to the invention with a large doorway aperture 41.

To accommodate the roof and wind loading on the lintel structure 42, the frame structures 43 are deeper and a plurality of uprights 44 are spaced along the top and bottom rail portions 43a, 43b between end members 43c, 43d. Uprights 44 are suitably pairs of rolled steel channel members secured in back to back relationship such that foam core blocks are secured by inwardly facing channel edge flanges extending about the peripheral edges of each core block Like the composite truss beam structure described with reference to FIGS. 7 and 8, the lintel structure 42, can be engineered to suit WO 02/101164 PCT/AU02/00759 12 the span by altering the height of the truss beam, the gauge of the steel channel members etc. Again, like the composite lintel structures of FIGS. 7 and 8, the lintel structure 42 ultimately relies upon encapsulation by the fibre reinforced polymeric skin in the region where it spans aperture 41 for its structural integrity.

FIG. 11 shows an alternative configuration of a masonry block suitable for erection of dry-stacked or mortarless wall structures.

Like the block of FIGS. 1-4, block 50 includes opposed side walls 51, opposed end walls 52 and intermediate webs 53 defining apertures 54, 55, 56 extending along upright axes through block On the upper face of block 50 there are formed projections 57 extending partly transversely of the block and having a shape and configuration to enable the projections 57 to meet in corresponding recesses 57a on the lower face of a corresponding adjacent block.

On the opposed side wall of block 50 are raised projections 58 forming a screed guide for a first layer of liquid curable polymeric adhesive.

After application of the liquid adhesive by spraying or trowelling, an initial adhesive layer of even thickness is formed over a wall surface by contact of a trowel or screed bar with the raised projections which act as a thickness guiding mechanism.

For masonry blocks formed by the "Besser"(Trade Mark) process, the projections 58 are suitably in the form of spaced vertically extending rib-like formations 59 having any desired spacing and any desired cross-sectional shape.

WO 02/101164 PCT/AU02/00759 13 As shown, the rib-like formations are regularly spaced and have a smooth undulating or "corrugated" shape with channel-like recesses therebetween. Alternatively, the ribs may be formed with a rectangular, part circular or a tapered V-shaped cross-section with a broad spacing therebetween.

For extruded clay or masonry blocks, the rib-like formations 59 will also extend parallel to each other and vertically as generally shown. For blocks made in demountable moulds, the pattern of surface projections on the side walls 51 of the blocks may be regular such as spaced circular or rectangular projections or they form an irregular pattern over the side walls 51. All that is required is that sufficient projections of a predetermined thickness are formed over the side walls of a block to permit a trowel or screed bar to contact the projections as the trowel or screed bar moves over the surface of the block wall to form an adhesive layer of even thickness thereover. This avoids waste in excessively thick layers of adhesive and otherwise serves to ensure a generally planar surface in the finished wall structure.

It readily will be apparent to a person skilled in the art that the wall building method according to the invention, and structures built therefrom, have substantial advantages over prior art masonry block structures requiring steel reinforcing in core filled walls.

The wall structures embody all of the structural insulating and fire rating qualities of conventional masonry block structure with the additional advantage of faster erection with less skilled labour and WO 02/101164 PCT/AU02/00759 14 consequent cost savings.

Further cost savings are obtained by avoiding the need for steel reinforcing in the wall structure and the need for concrete pumping to form the spaced steel reinforced cores as with prior art structures.

The high tensile fibre reinforced polymeric wall skins permits use of the structures in cyclone rated geographical regions and, in addition provide a much more weatherproof and vermin resistant structure than hitherto possible with conventional masonry finishes.

As an alternative to woven fibreglass reinforcing, non-woven fibreglass, woven or non-woven Kevlar, carbonfibre or synthetic fibrous mats may be used. The fibrous reinforcing may also include chopped fibres distributed throughout the polymeric coating material.

Throughout this specification and claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.

Claims (15)

1. 2. A method as claimed in claim 1 wherein said at least some of a base course of structural blocks are anchored directly to said base by a polymeric adhesive compound.
2. 3. A method as claimed in claim 1 or claim 2 wherein the structural blocks include one or more projections engageable, in use, with complementary one or more recesses in an adjacent structural block.
3. 4. A method as claimed in any preceding claim wherein said blocks are self-aligning when stacked. A method as claimed in any preceding claim wherein the structural blocks include one or more apertures extending between upper and lower faces thereof.
4. 6. A method as claimed in any preceding claim wherein the fibre reinforced polymeric coating extends over a top surface of said wall.
5. 7. A method as claimed in any preceding claim wherein mounting brackets are secured to an upper course of blocks in said wall to permit, in 16 use, connection of a roof structure to said wall.
6. 8. A method as claimed in any preceding claim wherein reveal surfaces in wall openings have applied thereto a fibre reinforced polymeric coating.
7. 9. A method as claimed in any preceding claim wherein said fibre reinforced polymeric coating includes a layer of fibreglass reinforcing material. A method as claimed in claim 9 wherein the layer of fibreglass material comprises a sheet of woven or non-woven fibreglass.
8. 11. A method as claimed in claim 9 or claim 10 wherein said fibreglass reinforcing material is an alkaline resistant grade.
9. 12. A method as claimed in any preceding claim wherein said fibre reinforced polymeric coating is formed by applying a base coating of a liquid curable polymeric composition to a wall surface, positioning on said base coating a layer of fibre reinforcing material, applying to an exposed surface of said layer of fibre reinforcing material a further coating of a liquid curable polymeric composition and allowing said liquid curable polymeric composition to cure.
10. 13. A method as claimed in claim 12 wherein the liquid curable polymeric composition is applied to a surface of the wall and/or the exposed surface of said layer of fibre reinforcing material by any suitable means including spraying, trowelling, screeding or squeegee application.
11. 14. A method as claimed in claim 12 or claim 13 wherein said base coating is applied to a substantially even thickness by means of guide projections extending from opposite normally exposed faces of said structural blocks. A method as claimed in claim 14 wherein said guide projections comprise spaced substantially parallel ribs serving, in use, to guide a screeding or trowelling device to apply said base coating to a substantially even thickness.
12. 16. A method as claimed in any preceding claim wherein a decorative coating is applied over the fibre reinforced polymeric coating.
13. 17. A method as claimed in claim 15 wherein the decorative coating comprises a polymeric mineral finish sealant.
14. 18. A wall structure whenever constructed in accordance with the method of any one of claims 1 to 16.
15. 19. A method for the construction of a structural block wall substantially as hereinbefore described with reference to the accompanying drawings. A block wall structure substantially as hereinbefore described with reference to the accompanying drawings. DATED this Twenty-first day of December 2006 HANSON BUILDING PRODUCTS PTY LTD By its Patent Attorneys FISHER ADAMS KELLY