AU665695B2

AU665695B2 - Cementitious building element

Info

Publication number: AU665695B2
Application number: AU41834/93A
Authority: AU
Inventors: Yves Pierre Marcel Treuil
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-07-08
Filing date: 1993-07-07
Publication date: 1996-01-11
Anticipated expiration: 2013-07-07
Also published as: AU4183493A

Description

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AUSTRALIA

Patents Act 1990 P/00/01 1 28/WJ91

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT CCA e N 'f T 13-S a-ktL6tw(. E LEM CW he following statement is a full description of this invention, including the best -m"rethod of performing it known to me:- 4 II.. .4 1

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j 1 CEMENTITIOUS BUILDING ELEMENTS 2 TECHNICAL FIELD 3 The present invention relates to the manufacture of 4 cementitious building elements and in p:articular but not exclusively to cementitious building blocks and a method of 6 producing same.

The invention was devised primarily to produce :oo 8 building blocks having one or more faces similar in texture and o 9, appearance to sandstone and is described in relation thereto .oo .i hereinafter, but it will be appreciated that the invention is ,.o1T applicable to building elements generally.

12 In conventional methods of manufacturing 13 cementitious building blocks, a relatively fluid uncured o 1 4 cementitious material is poured into a mould cavity, the uncured material is then consolidated with a spade or vibrator to -o :16 reduce air pockets trapped therein and then allowed to cure to 17 form a cementitious block. At times the mould cavity is lined or 18 treated with a parting membrane or layer to prevent o °19 cementitious material adhering to the mould. An object of the a Q a present invention is to provide a novel building block and/or a 21 novel method of manufacturing a building block.

22 DISCLOSURE OF THE INVENTION 1 2 3 4 6 o 12 13 0 16 22 23 0404 o I_ o o w n o 1 2 13 23 According to one aspect the invention provides a method of manufacturing a cementitious building element comprising the steps of placing wetted non flowable uncured cementitious material into a mould having a cavity tamping said non flowable material into the mould cavity pouring wetted relatively fluid flowable uncured cementitious material into the mould cavity whereby one material overlays the other then allowing the materials to cure and discharging the cured element from the mould.

Preferably the method further comprises the step of providing at least one insert within the mould cavity prior to the step of pouring wetted relatively fluid flowable uncured cementitious material into the mould cavity thereby to produce an element having at least one hollow core.

Alternatively the method may further comprise the step of providing at least one insert within the mould cavity concurrent with the step of pouring wetted relatively fluid flowable uncured cementitious material into the mould cavity thereby to procluce an element having at least one hollow core.

Preferably the mould cavity has a bottom surface provided with a pattern and/or shape to be impressed into the i F- j 1 2 3 4 6 .7 4' 12 13 14 16 17 18 21 22 23 24 non flowable material to produce an element having said pattern and/or shape respectively on a surface thereof.

More preferably the pattern and/or shape impressed into a face of the building element to gives it the appearance of carved or natural sandstone.

In some embodiments the at least one hollow core within the mould cavity extends between a pair of upright side walls of the mould cavity.

The cementitious material may, for example, be comprised of a lightweight concrete. The concrete may, for example, be comprised of cement, water, sand and a lightweight granulate material. The lightweight granulate material may be comprised of expanded polystyrene granules or beads. More preferably the granulate material has its surface modified by treatment adapted to facilitate even distribution in the concrete.

The granulate material may, for example, have its surface modified by treatment with protein material imparting negative electrokinetic potential thereto to facilitate said even distribution in the concrete.

Alternatively the cementitious material may be comprised of a mortar. The mortar may, for example, be comprised of cement, water and sand. Preferably the cement is in the form of off-white cement and the sand is clean river sand, preferably yellow or white.

4 1 According to a second aspect the invention provides a 2 method of manufacturing a composite cementitious building 3 element comprising the method according to the first aspect 4 wherein the non-flowable material comptrises a mortar and the flowable material comprises a concrete.

6 According to a third aspect the invention provides a 7. cementitious building e-linmet having a face similar in texture 4\*8 and appearance to sandstone manufactured by a method 9, according to the first aspect and/or a method according to the 0« second of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS 12 By way of example some embodiments of the above 13 described invention will be described in more detail hereinafter S14 with reference to the accompanying drawings, in which- Figure 1 is an isometric view of a building block 16 produced by a method in accordance with the invention 17 Figure 2 is an isometric view of another building block 18 produced by a method in accordance with the invention 19 Figure 3 is an isometric view of yet another building block produced by a method in accordance with the invention 21 Figure 4 is an isometric view of a further building block 22 produced by a method in accordance with the invention 23 DETAILED DESCRIPTION r it 1 Figures 1 and 4 each illustrate embodiments of a 2 cementitious building element in the form of a composite 3 building block 1 having one face 2 similar in texture and 4 appearance to sandstone is moulded from a mortar mix integral with a layer of lightweight concrete.

6 The mould (not shown) used tO form the block 1 7 illustrated in Figures 1 and 4 has a cavity comprising a bottom 8 surface provided with a pattern and/or shape to be impressed 9 into the face 2 of the block to give it the appearance of carved or natural sandstone, and upright side walls extending from the :1 periphery of the bottom surface.

12 To produce the block illustrated in Figures 1 and 4 a 13 wetted non flowable uncured cementitious material in the form 14 of a mortar of sand, cement and water is prepared. The sand is clean river sand, preferably yellow or white. The cement is in the 16 form of off-white cement or a mixture of white cement and a 17 colorant. Sufficient water is added to a dry mix of said sand and 18 cement to produce a non flowable uncured mortar with a low 19 flow property. That is to say, an uncured mortar that does not stick to mould surfaces once cured.

21 A simple test for low flowability is to pick up a handful 22 of mortar in the palm of the hand and squeeze it into a ball. If 23 the handful of mortar remains in a ball when the hand is opened 6 1 without parts of it sticking to parts of the hand then the mortar is 2 of low flowability.

3 The ratio of sand to cement is in the order of four to one 4 In small batch operations, eighty kilograms of sand is mixed with twenty kilograms of cement and about eight litres of 6 water.

7 A wetted relatively fluid flowable uncured cementitious material in the form of a lightweight concrete is also prepared.

9 That is to say, an uncured lightweight concrete with a high flow property.

11 The lightweight concrete comprises cement, water, sand and expanded polystyrene granules or beads. The granules or 13 beads have their surface modified by chemical treatment to 14 facilitate even distribution in the concrete. The beads are pretreated with a commercially available chemical dispersing agent.

such as "Betostyrene" (Australian Trade Mark Registration 17 Number 505692), "BST"(Australian Trade Mark Number 554131) 18 or the like. "Betostyrene" is thought to include protein material 19 which imparts negative electrokinetic potential to the beads oo: 20 thereby facilitating said even distribution in the concrete.

S. 21 In small batch operations, eighty-five kilograms of sand, 22 one hundred and fifty kilograms of cement, four hundred litres 23 of pre-treated expanded polystyrene granules or beads and twenty 24 four litres of water are mixed to form a lightweight concrete with l+ V

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ir 7 1 a density of about seven hundred kilograms per cubic metre, after 2 seven days.

3 The mortar is trowelled into the mould cavity and 4 tamped down into the bottom of the mould cavity to impress the pattern and/or shape into the face of the mortar and to 6 substantially reduce air pockets therein.

7 Preferably before the mortar has set, the lightweight 8 concrete is poured into the mould to overlie the mortar and thus 9 substantially fill the cavity.

The cementitious materials may be retained in the 11 mould for at least twenty four hclrs before beir~ discharged ;1'2 therefrom.

13 This method produces a composite building block 1 14 having one face 2 (a mortar surface) replicating sandstone formed integrally with a lightweight backing layer of concrete without 16 the use of adhesives or like chemicals and without the use of 17 mechanical fastening means. It hr been found that the use of 18 low flowability mortar reproduces a superior "non-stick" pattern 19 than the use of high flowability mortar. That is to say, it 20 produces a block having a pattern that substantially does not stick S 21 to the mould. It has also been found that the use of treated 22 expanded polystyrene granulate concrete improves the non-stick 23 characteristics of high flowability cementitious material and

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111 I| 11 11 1 1- -1 1.;,..~~4alUn7~4Y-rCii_ 1 2 3 4 6 7 0 i i S.12 13 14 18 .19 20 21 22 23 24 k 1 ned .out i of of :ern it tick Lted tick and improves the thermal insulation characteristics or properties of conventional building blocks.

Figure 2 and 3 each illustrate other embodiments of a cementitious building element in the form of a composite building block 1 having two faces 2, 3 respectively similar in texture and appearance to sandstone moulded from a mortar mix integral with a layer of lightweight concrete formed by a method substantially as described above wherein the bottom and one side wall of the mould cavity is prrvided with the pattern and/or shape to be impressed into the front face and side face of the block. In these embodiments the step of trowelling and tamping down the mortar into the mould cavity comprises trowelling and tamping down into the bottom and one side wall of the mould cavity to impress the pattern and/or shape into the face of the mortar prior to the step of pouring the lightweight concrete into the mould to overlie the mortar and thus substantially fill the cavity.

In regard to embodiments of building element according to the invention illustrated in Figures 3 and 4 they differ from the embodiments illustrated in Figures 1 and 2 respectively in that they are each formed with a pair of hollow cores 4 extending therethrough. Each element comprises a block 1 of rectangular cross-section (590mm x 260mm x 200mm) having two substantially identical hollow cores 4 (each 100mm x 60mm x 'i' s~i 1. :I 9 1 200mm) therethrough. The cores 4 are moulded into the blocks 2 during manufacture. The pair of inserts are provided within the 3 mould cavity prior to the step of pouring the concrete into the 4 mould cavity. Alternatively the pair of inserts may be provided within the mould cavity concurrent with the step of pouring the 6 concrete into the mould cavity. Each insert extends from one 7 side wall of the mould cavity to an opposite side wall. That I, to say, each insert extends the width of the mould cavity. In one Oit 9 particular embodiment, one end of each insert is threaded through a respective slot in one side wall into the cavity then 11 through a respective slot in an opposite side wall. In another S12 embodiment said one end is emplaced in a recess in said opposite 13 side wall 14 Typically a block having a pair of hollow cores weighs in the order of fifty five kilograms when moulded of mortar and in S6 the order of thirty two kg. when moulded of a composite of S* 17 mortar and treated lightweight concrete. Typically the thickness 18 of the mortar layer in a composite block is in the order of fifty ono19 millimetres to eighty millimetres.

0 go 20 The building block according to the invention illustrated 21 in Figures 1 and 2 each comprises a composite block 1 of 22 rectangular cross-section (590mm x 260mm x 90mm) without 23 hollow cores having a mortar layer of typically thirty millimetres 24 thick and a lightweight concrete layer sixty millimetres thick.

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1 Such i block typically weighs in the order of twelve kilograms, 2 whereas a corresponding block of mortar material alone weighs 3 in the order of twenty-five kilograms.

4 Details of the preferred embodiments are given by way of example only and it is to be understood that many variations and 6 modifications will fall within the scope of the appended claims.

7 For example the preferred embodiments describe a building block 8 having one face or two faces having the appearance of carved or 9 ,9 natural sandstone however building blocks having three such ,,ao faces may be manufactured using a method according to the S11 invention. Further the bottom surface of the mould cavity may be in the form of a member readily emplacable and removable 13 from the mould cavity.

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Claims

2. A method according to claim 1 further comprising the 13 step of providing at least one insert within the mould cavity 14 prior to the step of pouring wetted relatively fluid flowable uncured cementitious material into the mould cavity thereby to 16 produce an element having at least one hollow core. t,«17 3. A method according to claim 1 further comprising the 18 step of providing at least one hollow insert within the mould 19 cavity concurrent with the step of pouring wetted relatively fluid 20 flowable uncured cementitious material into the mould cavity 21 thereby to produce an element having at least one hollow core. 22 4. A method according to any one of the preceding claims 23 wherein the mould cavity has a bottom surface provided with a 24 pattern and/or shape to be impressed into the non flowable ;l F 12 1 material to produce an element having said pattern and/or shape 2 respectively on a surface thereof. 3 5. A method according to any one of the preceding claims i 4 wherein the mould cavity comprises a bottom surface provided with a pattern and/or shape to be impressed into the face of the 6 building element to give it the appearance of carved or natural 7 sandstone, and upright side walls extending from the periphery 8 of the bottom surface. 9 6. A method according to claim 5 further comprising the step of providing at least one hollow insert within the mould 11 cavity extending between a pair of said upright side walls prior to 12 the step of pouring wetted relatively fluid flowable uncured 13 cementitious material into the mould cavity thereby to produce 14 an element having at least one hollow core. S13 7. A method according to claim 5 further comprising the 16 step of providing at least one hollow insert within the mould S:17 cavity extending between a pair of said upright side walls 18 concurrent with the step of pouring wetted relatively fluid flowable uncured cementitious material into the mould cavity 20 thereby to produce an element having at leaas one hollow core. 21 8. A method according to any one of the precedimg claims 22 wherein at least one of said cementitious materials comprises a 23 mortar. L.' r 13 1 9. A method according to claim 8 wherein said mortar 2 comprises cement, water and sand. 3 10. A method according to any one of claims 1 to 7 wherein 4 at least one of said cementitious materials comprises a concrete.
11. A method according to claim 10 wherein said concrete 6 comprises cement, water, sand and a lightweight granulate 7 material.
12. A method according to any one of claims 1 to 7 wherein 9 said non flowable material comprises a mortar and said flowable 1 0 material comprises a concrete thereby to produce a composite cementitious building element. 12 13. A method according to claim 12 wherein said concrete 13 comprises cement, water, sand and a lightweight granulate 14 material. f 15 14. A method according to claim 13 wherein said 16 lightweight granulate material comprises expanded polystyrene "17 granules or beads. I 18 15. A method according to any one of claims 11, 13 or 14 19 wherein said granulate material has its surface modified by o o treatment adapted to facilitate even distribution in the concrete. 21 16. A method according to claims 15 wherein said treatment 22 comprises treating the granulate material with protein material 23 thereby imparting negative electrokinetic potential thereto. ST L S. i F/
17. A method according to any one of claims 11 to 16 wherein the cement is in the form of off-white cement and the sand is clean yellow or white river sand,
18. A cementitious building element manufactured by a method according to any one of the preceding claims.
19. A method of manufacturing a cementitious building element substantially as hereinbefore described. A cementitious building element substantially as hereinbefore described with reference to the drawings. Dated this tenth day of August 1995 YVES PIERRE MARCEL TREUIL t I I It LIJ 1 2 3 4 6 7 8 9 i4 12 13 ABSTRACT A cementitious building block and a method of producing same having one or more faces similar in texture and appearance to sandstone is described. A method of manufacturing a cementitious building element comprises the steps of placing wetted non flowable uncured cementitious material into a mould having a cavity tamping said non flowable material into the mould cavity pouring wetted relatively fluid flowable uncured cementitious material into the mould cavity- whereby one material overlays the other then allowing the materials to cure and- discharging the cured element from the mould. A method of manufacturing a composite cementitious building element is also described. 14 r% I 4 44 4 *a I 4 4.1 4:> ;4,4' 7-Q- I 1