AU762548B2 - A cementitious composition for inhibiting the formation of efflorescence - Google Patents

Description

WO 00/14027 PCT/AU99/00720 -1- A CEMENTITIOUS COMPOSITION FOR INHIBITING THE FORMATION OF EFFLORESCENCE Field Of The Invention The present invention relates generally to a setable cementitious composition particularly suitable for coating masonry, cement fibreboard, concrete and for forming concrete items and structures. The invention also relates to a method of preparing the composition and its use.

Background Of The Invention It is known to mix Portland cement with sand and optionally fine and/or coarse aggregate in the preparation of dry cementitious compositions for being mixed with sufficient water to form renders or coatings for being applied to suitable surfaces by brush, trowel or spraying techniques. If desired, the compositions may be coloured with the use of oxide pigments. Such compositions can be prepared either in small batches at the work site for convenience, or in large batches in off-site factories for accurate proportioning of the ingredients and consistency of colour and texture.

However, the compositions in the absence of added water are prone to the generation of dust hazards when handled. They are also not particularly resistant to moisture penetration when set and for this reason, it is known to modify them by the addition of for example, acrylic based emulsion or powder preparations, to enhance their resistance to moisture penetration. Such acrylic materials are typically significantly more expensive per unit mass then the other components in the composition.

WO 00/14027 PCT/AU99/00720 -2- Preparation at the work site of small batches of the above compositions generally involves poor control over the colour and texture of the resulting mix and undesirable variation in properties of the finished coating due to proportioning and mixing difficulties inherent in the process. Problems resulting from particle size separation and component stratification of dry ingredients due to vibration experienced during transport create similar difficulties within factory prepared batches. As a result of such difficulties, cementitious compositions of the above type are little used today even though they are relatively inexpensive compared to conventional exterior grade paints, easy to apply and are durable.

Compositions of the type described above are also utilised in the manufacture of for instance, preformed walls, paving blocks, footpaths and cast concrete slabs used for vehicular driveways. However, it is common for efflorescence to form on the surface of the cured concrete in situ. Efflorescence results from the transport of soluble salts from below or within the concrete by water to the surface of the concrete, which subsequently evaporates leaving a deposit behind. Generally, the efflorescence is in the form of a white or grey deposit which forms progressively with time and can obscure exposed coloured surfaces of the concrete or exposed coloured aggregates in the concrete.

It is known to acid wash concrete and masonry surfaces to remove efflorescence and to coat the surfaces with water repellent coatings such as those based on siloxanes or solvent based acrylics to ameliorate the formation of efflorescence. However, the treatments are relatively expensive and are carried out WO 00/14027 PCT/AU99/00720 -3after the formation of the concrete or masonry structure which is time consuming and contributes to increased labour and thereby manufacture or installation costs.

Australian Patent Application No. 13296/83 discloses a Portland cement composition incorporating asphalt and a small amount of carbon black. The preparation of the composition involves mixing the asphalt with dry Portland cement and agitating the mixture at a temperature of between about 100°C and 180'C to thereby coat the particles of the cement with a thin film of asphalt. The filmed cement particles are then mixed with the carbon black.

The asphalt and carbon black act to fill pores in the set cement that may have formed as a result of excessive hydration and due to the presence of air entrapped during the mixing of the composition for use, thereby enhancing the resistance of the set cement to permeation by water. The asphalt films around the Portland cement particles also inhibit cracking by absorbing some of the heat that arises due to the hydration of the cement.

However, the problems of component separation and stratification of at least the carbon black resulting from storage or vibration experienced during transport remain. The process of coating the Portland cement particles with the asphalt is also relatively involved requiring suitable apparatus for heating the asphalt while being agitated with the Portland cement.

In EP 0755982 there is disclosed a two part grouting composition. Part A of the composition comprises an asphalt emulsion, a hydraulic inorganic material, a water-soluble resin and water. Part B also comprises an asphalt emulsion as well as a hydraulic inorganic material, a polymerisation catalyst and water. Portland cement is -4described as being suitable for use as the hydraulic inorganic material while the part A and part B mixtures are described as being in liquid form. When mixed together, the resin is caused to polymerise and the resulting composition to thereby set. Accordingly, the grout is only suitable for applications where it is to be used immediately upon the mixing of the parts A and B.

Summary of the Invention It is an aim of the present invention to ameliorate one or more problems of the prior art or to at least provide a useful cementitious composition.

In one aspect of the invention there is provided a cementitious composition in the form of a substantially free flowing powder comprising a hydraulic cement; and a hydrocarbon binder mixed in at least one organic solvent, said hydrocarbon binder being substantially solid or semi-solid at ambient temperature; wherein the composition contains a combined volume of the hydrocarbon binder o, 15 and organic solvent in a range of from about 0.50 to about 20 litres per 100 kg of the l hydraulic cement, and the composition is settable by hydration of the cement with sufficient water.

The hydraulic cement will generally be a hydraulic cement of the type conventionally used in the formation of concrete structures and may be ordinary Portland cement, an off-white cement, a white cement, a high alumina cement, a slag cement, a flyash cement, a cement fondu, a gypsum cement or mixtures of such cements.

The term hydrocarbon binder where ever used herein is to be taken to mean a binder consisting of or comprised largely of one or more hydrocarbon compounds, that is capable of substantially dissolving in the organic solvent and being dispersed essentially throughout the cement to inhibit the passage of water through the composition of the invention when set.

The hydrocarbon binder may for instance be a bituminous binder, a tar such as a coal tar or wood tar, a pitch, a wax such as paraffin wax, or a mixture of such substances. Preferably, the hydrocarbon binder will be a bituminous binder.

The bituminous binder may be selected from the group consisting of bitumen, asphalts, asphaltic pyrobitumens, mineral waxes and mixtures of the foregoing.

Preferably, the bituminous binder will be bitumen.

The organic solvent may be any hydrocarbon solvent suitable for substantially dissolving the hydrocarbon binder and for being dispersed throughout the cementitious composition. The solvent acts as a carrier for the hydrocarbon binder and facilitates the dispersion of the binder essentially throughout the cementitious composition. Typically, the organic solvent will be kerosene (liquid paraffin), diesel oil, light fuel oil, turpentine, white spirit or other liquid petroleum derivate.

In a second aspect of the invention there is provided a method of preparing a l cementitious composition in the form of a substantially free flowing powder comprising mixing a hydrocarbon binder with a hydraulic cement and at least one organic solvent disperse said binder and the solvent essentially throughout the cement, said hydrocarbon binder being substantially solid or semi-solid at ambient temperature, wherein the composition contains a combined volume of the hydrocarbon binder and organic solvent in a range of from about 0.50 to about 20 litres per 100 kg of the hydraulic cement, and the composition is settable by hydration of the cement with sufficient water.

Preferably, the hydrocarbon binder will be mixed with the organic solvent prior S• to the addition of the resulting mixture to the hydraulic cement.

Water in an amount sufficient to cause the hydraulic cement and thereby the composition itself to set, will normally be added after the hydraulic binder has been dispersed through the cement. The mixing of the components of the cementitious- 0 000.

0.

0: 00 WO 00/14027 PCT/AU99/00720 -6composition will generally be achieved by physical agitation of the ingredients as is commonly known such as with use of conventional cement mixing apparatus.

The cementitious composition may be prepared at the work site or remotely therefrom and transported to the work site with or without water added.

It has been found by the present inventors that the addition of the hydrocarbon binder and the organic solvent substantially minimises dust formation from the resulting mixture in the absence of any added water. In addition, it has been found that component separation and stratification, due to vibration experienced during transport or resulting from storage, may be substantially inhibited.

Furthermore, despite the black colour of many hydrocarbon binders, their use as described herein does not necessarily result in the cementitious composition taking on a black colour and indeed, white and coloured compositions may be achieved.

Moreover, it has been surprisingly found that the presence of the hydrocarbon binder and organic solvent in embodiments of the composition do not inhibit the setting time of the hydraulic cement to any significant degree and the compositions may remain in the form of a substantially freely flowing powder until the addition of water immediately prior to use.

Advantageously, structures, coatings or renders formed from the cementitious composition of the invention may be more resistant to the formation of efflorescence compared to corresponding structures formed with prior art compositions.

In still another aspect of the invention there is provided a product prepared from a cementitious composition as herein described.

WO 00/14027 PCT/AU99/00720 -7- The invention will now be described with reference to a number of preferred, non-limiting embodiments.

Best Mode Of Carrying Out The Invention Preferred cementitious compositions of the invention remain in the form of a substantially freely flowing powder mixture following the addition of the hydrocarbon binder and organic solvent to the hydraulic cement and the subsequent mixing together of those materials.

Wetting of the hydraulic cement by water droplets is inhibited by the presence of the hydrocarbon binder and the organic solvent. Accordingly, hydration of the hydraulic cement and setting of the mixture may be substantially avoided until it is desired to use the composition. This allows the composition to be prepared in advance, transported and stored until it is required.

Setting of the mixture can be achieved by the addition of sufficient water and mixing under high shear as can be readily achieved with the use of a trowel or conventional cement mixer.

SThe composition of the invention may further comprise one or more fillers and texturing agents for providing the composition with a desired texture. Suitable such materials include fine and/or coarse aggregates such as sand, gravel, particulate granite commonly known as decomposed granite and crushed stone, rock, minerals and slag (also known as cinder).

The composition may also include one or more additives such as colorants including iron oxides and dyes or pigments deemed suitable, whitening agents such as titanium dioxide, limestone, dehydroxylated clays and metakaolin clays, plasticisers WO 00/14027 PCT/AU99/00720 -8such as hydrated lime and bentonite clays and including super plasticisers, water reducing agents and water retention agents, set accelerators and set retarders, viscosity modifiers including clays, thickeners such as hydroxymethylcellulose, cellulose ethers and cellulose alcohols, thixotropes including aerosils, film formers and glossing agents such as aluminium stearate and other metallic soaps. Other possible additives include matting agents such as ground silica and fumed silica, water proofing agents such as waxes, acrylic preparations conventionally used in cement compositions for that purpose, botanical oils including eucalyptus and pine oils, and odour masking agents.

The amounts of such additives if included in the composition will vary depending on the desired outcome and the required consistency of the composition.

The amounts can be readily determined by the skilled addressee in accordance with conventional knowledge of the use of such substances in cements.

The combined weight of any additives will normally comprise less than about 20% of the weight of the cementitious composition prior to the addition of water for causing the composition to set.

Generally, the hydrocarbon binder will be mixed into the organic solvent such that the binder is caused to be substantially dissolved prior to the addition of the resulting mixture to the hydraulic cement and any fillers and/or texturing agents.

Preferably the volume ratio of hydrocarbon binder to organic solvent will be between 1:1 and 1:50, more preferably between 1:2 and 1:25 and most preferably, between 1:4 and 1:15. Desirably, the hydrocarbon binder and organic solvent mixture will have a WO 00/14027 PCT/AU99/00720 -9consistency that readily enables the binder to be dispersed through the hydraulic cement and other ingredients present.

Preferably, between about 0.50 and about 20 litres of the hydrocarbon binder and organic solvent mixture is added per 100 kg of cement, more preferably between about 1.0 and 10.0 litres and most preferably, between about 2.0 and 6.0 litres.

In compositions in which fillers and/or texturing agents are used, an additional amount of between about 0.2 and about 10.0 litres of the hydrocarbon binder and organic solvent mixture may be added per 100 kg combined weight of the filler and texturing agents, more preferably between about 0.4 and about 5.0 litres and most preferably, between about 0.5 and about 3.0 litres.

Usually, the weight proportion of hydraulic cement to the combined weight of any fillers and texturing agents will usually be between about 1:0.1 and about 1:25.

When the cementitious composition is to be used as a paint or render the weight proportion will usually be between about 1:1 and about 1:3, whereas when the composition is to be used to form a precast cementitious or concrete item it will usually be from about 1:3 to about 1:6. In the instance of concrete paths and driveways the weight proportion will normally be between about 1:6 to about 1:25.

Once the hydrocarbon binder and organic solvent mixture has been mixed thoroughly into the hydraulic cement and the fillers and/or texturing agents if any, the water is added and also mixed in. The amount of water added will depend on the desired consistency of the composition and the purpose for which the composition is to be used.

WO 00/14027 PCT/AU99/00720 In one form of the invention, the hydrocarbon binder for being added to the hydraulic cement may be in the form of a water-in-oil emulsion. Bituminous water-inoil emulsions are particularly preferred. In this instance, it has been unexpectedly found that the water in bituminous emulsions can be inhibited from wetting the hydraulic cement by the presence of the oil and the organic solvent, such that setting or hardening of the cementitious composition is not initiated. The resulting composition although containing some water is generally dry to the touch and can remain in a substantially freely flowing powder form essentially unchanged to the eye or touch for up to three months or more following preparation until use.

Oil-in-water emulsions may be utilised but will generally be mixed into the desired organic solvent to convert them into water-in-oil emulsions prior to the addition of the resulting mixture to the hydraulic cement.

Suitable bituminous emulsions for use in the preparation of a cementitious composition of the invention are commercially available such as from CSR Limited (Sydney, Australia) under the Emolueum brand and include emulsions of the cationic, anionic and non-ionic type. The ionic and non-ionic nature of such emulsions is dependant on the surfactants used.

As described above, compositions of the invention find application as paints, renders and for forming cement and concrete slabs. Accordingly, the amount of water added to cause a given composition to set will be appropriate to obtain the necessary consistency. In the case of a paint, the consistency will be such as to allow the composition to be applied with use of a brush of a spraying technique. In the case of a render the consistency will be appropriate to allow the composition to be applied with WO 00/14027 PCT/AU99/00720 -11a trowel. In each instance, the amount of water required can be readily determined by the skilled addressee by adding a small amount of water, mixing it in and repeating those steps until the desired consistency is achieved. For larger batches, a small test batch can be prepared to allow the proportionate amount of the water required to be determined.

The additives if any will generally have been mixed with the hydraulic cement prior to the addition of the water, although super plasticisers will typically be add-d after the addition of the water.

The invention will now herein after be described with reference to a number of examples of cementitious compositions of the invention. Unless otherwise stated, all ingredient amounts of mixtures are expressed in terms of weight of the ingredient per weight of the relevant mixture.

Example 1 A dry conventional cementitious mixture was prepared as follows.

Ingredients Weight Portland Cement 36.1% Fine sand 62.8% Iron oxide pigment 1.1% Total 100.0% A bituminous mixture was also prepared comprising a bituminous binder and organic solvents as set out below.

WO 00/14027 PCT/AU99/00720 -12- Bituminous Mixture Ingredients Volume Bitumen/kerosene mixture 36 litres Kerosene 100 litres Diesel oil 15 litres Total 151 litres The bitumen/kerosene preparation is commercially available from Boral Limited (Sydney, Australia) under the trade name Cut Back Asphalt and comprises bitumen and 55% kerosene by weight.

A cementitious composition of the invention was then prepared from parts A and B as follows utilising the bituminous mixture prepared above.

Part A Ingredients Weight Portland cement 93.7% Iron oxide pigment 2.8% Bituminous mixture Total 100.0% Part B Ingredients Weight Fine sand 100.0% Quantities of parts A and B were subsequently thoroughly mixed to form a formulation C comprising 38% w/w of the part A mixture and 62% w/w of the part B mixture.

When the conventional cementitious mixture was poured from one bucket into another, it gave rise to a small but noticeable cloud of dust. When an equivalent amount of the formulation C was poured from one bucket into another, no expelled dust was observed.

WO 00/14027 PCT/AU99/00720 -13- In another test, equal amounts of the conventional mixture and formulation C were placed into separate clear glass containers and vibrated vigorously simultaneously for about 1 minute on a vibrating table to simulate the effects of transport. It was observed that the conventional mixture stratified into layers with the Portland cement forming a layer under the other ingredients. No stratification of the formulation C preparation was observed.

Example 2 Suffi-;ent water was mixed with an amount of the formulation C mixture from Example 1 to form a dull red paintable mixture which was subsequently applied by brush as a coating to a pre-wetted concrete masonry block and allowed to set. The set coating was occasionally sprayed with water over the first 24 hours after application. The resulting coating formed was determined to be attractive and serviceable.

Example 3 An open end of a 1.5 metre length of 150 mm nominal bore rigid polyvinyl chloride (PVC) pipe was secured flushly to the coated surface of the masonry block of Example 2 using a silicone sealant as an adhesive. Care was taken to ensure that the coating on the masonry block across the open end of the pipe remained free of the silicone sealant.

The block was then arranged horizontally so that the PVC pipe was disposed substantially vertically above the block. The pipe was subsequently filled with water to the maximum water column height of 1.5 m and the level of water observed periodically. No further additions of water were made to the water column. After 24 WO 00/14027 PCT/AU99/00720 -14hours there had been no noticeable drop in the height of the water column indicating no significant water permeation of the coating demonstrating its effective moisture penetration resistance.

Example 4 A conventional cementitious mixture comprising three parts of sand, one part of Portland cement and a small amount of iron oxide pigment was mixed with sufficient water to form a composition having a mouldable consistency prior to being compressed into a mould to form a concrete paving block and allowed to cure. A test composition consisting of three parts of fine sand, one part of the part A cementitious composition of Example 1 and a small amount of iron oxide pigment was mixed with water to form a mixture having a consistency as for the conventional mixture described above, prior to the mixture being compressed into a mould to also form a concrete paving block which was subsequently allowed to cure.

Both the conventional and test paving blocks were partially immersed in water. After four days of partial immersion, the exposed surfaces of the conventional paving block were heavily coated with efflorescence, while the exposed surfaces of the test paving block were essentially free of efflorescence.

Example A conventional cementitious mixture consisting of approximately 5% to by weight of Portland cement and the remainder of particulate granite was mixed dry and placed within the form work for a pathway. Water was added to the mixture insitu, prior to the resulting composition being compacted in the conventional manner and allowed to cure until hard. A test composition consisting of approximately 5% to WO 00/14027 PCT/AU99/00720 by weight of Portland cement and bituminous mixture of Example 1 in an amount of 3.5% w/w of the Portland cement with particulate granite making up the remainder of the composition was mixed and again placed within the form work for a pathway. Water was also added to the test composition in-situ which was then compacted and allowed to cure until hard as above.

Both the resulting conventional and test concrete pathways were inspected after several days. It was observed that the conventional pathway was coated with efflorescence while the pathway formed with the test cementitious composition was essentially free of efflorescence.

Example 6 A bituminous mixture was prepared using a cationic bituminous oil-in-water type emulsion commercially available from Boral Limited (Sydney, Australia) under catalogue reference CRS, as follows.

Bituminous Mixture Ingredients Volume Cationic bituminous water-in-oil emulsion 36 litres Kerosene 100 litres Diesel oil 15 litres Total 151 litres A cementitious coating composition was then prepared from parts E and F.

Part E Ingredients Weight Portland cement 93.7% Iron oxide pigment 2.8% Bituminous mixture Total 100.00% WO 00/14027 PCT/AU99/00720 -16- Part F Ingredients Weight Fine sand 100.0% Quantities of parts E and F were combined and thoroughly mixed to form composition G comprising 38% w/w of the part E mixture and 62% w/w of the part F mixture.

The composition G mixture was dry to the touch, despite the presence of the water from the bituminous emulsion and had the form of a freely flowing dust free powder. After three months it was observed that the composition G mixture remained in essentially the same form with no indication of hydration of the cement.

Example 7 A quantity of the composition G mixture from Example 6 was mixed with sufficient water to form a dull red paint which was applied by brush as a coating to a pre-wetted concrete masonry block and allowed to set. The set coating was occasionally sprayed with water over the first 24 hours after application. The resulting coating formed was attractive and serviceable.

Example 8 A wax based mixture was prepared using paraffin wax in the proportions as follows.

Wax Mixture Ingredients Volume Paraffin wax 36 litres Kerosene 100 litres Diesel Oil 15 litres Total 151 litres WO 00/14027 PCT/AU99/00720 -17- A cementitious coating composition was also prepared from parts K and L describe below.

Part K Ingredients Weight Portland cement 93.7% Iron oxide pigment 2.8% Wax mixture Total 100.0% Part L Ingredients Weight Fine sand 100.0% Quantities of parts K and L were then combined and thoroughly mixed together. The resulting composition was observed to have the form of an essentially dry, freely flowing substantially dust free powder.

Example 9 A quantity of the cementitious coating composition from Example 8 was mixed with sufficient water to form a dull red paint which was applied as a coating to a pre-wetted concrete masonry block and allowed to set. The set coating was occasionally sprayed with water over the first 24 hours after application. The resulting coating formed was attractive and serviceable.

Although the invention has been described hereinbefore with reference to a number of preferred embodiments, the skilled addressee will appreciate that numerous variations and modifications are possible without departing from the scope of the invention.

Claims (36)

1. A cementitious composition in the form of a substantially free flowing powder comprising a hydraulic cement; and a hydrocarbon binder mixed in at least one organic solvent, said hydrocarbon binder being substantially solid or semi-solid at ambient temperature; wherein the composition contains a combined volume of the hydrocarbon binder and organic solvent in a range of from about 0.50 to about 20 litres per 100 kg of the hydraulic cement, and the composition is settable by hydration of the cement with sufficient water.

2. A composition according to claim 1 wherein the composition has a volume ratio of the hydrocarbon binder to the organic solvent of from about 1:1 to about 1:50.

3. A composition according to claim 2 wherein the volume ratio of the hydrocarbon binder to organic solvent is from 1:2 to 1:25.

4. A composition according to claim 2 or 3 wherein the volume ratio of the hydrocarbon binder to organic solvent is from 1:4 to 1:15. A composition according to claim 1 wherein the combined volume of the hydrocarbon binder and the organic solvent is in a range of from about 1 litre to about litres.

6. A composition according to claim 5 wherein the combined volume of the Shydrocarbon binder and the organic solvent is in a range of from 2 litres to 6 litres.

7. A composition according to any one of claims 4 to 6 further comprising one or more fillers and/or texturing agents. -19-

8. A composition according to claim 7 further comprising an additional volume of the hydrocarbon binder and the organic solvent of from about 0.2 litres to about 10 litres per 100 kg combined weight of the filler and/or texturing agents.

9. A composition according to claim 8 wherein the additional volume of the hydrocarbon binder and the organic solvent is between 0.4 litres and 50 litres. A composition according to claim 9 wherein the additional volume of the hydrocarbon binder and the organic solvent is between 0.5 and 3.0 litres.

11. A composition according to any one of claims 1 to 4 further comprising one or more fillers and/or texturing agents.

12. A composition according to any one of claims 7 to 11 wherein the composition has a weight ratio of the hydraulic cement to the fillers and/or texturing agents of between about 1:0.1 and about 1:25.

13. A composition according to claim 12 wherein the weight ratio of the hydraulic cement to the fillers and/or texturing agents is between 1:1 and 1:3.

14. A composition according to claim 12 wherein the weight ratio of the hydraulic cement to the fillers and/or texturing agents is between about 1:3 and 1:6.

15. A composition according to claim 12 wherein the weight ratio of the hydraulic cement to the fillers and/or texturing agents is between about 1:6 and 1:25.

16. A composition according to any one of claims 7 to 15 wherein the fillers and/or aggregates are selected from the group consisting of sand, gravel, slag, stones, rocks and minerals.

17. A composition according to any one of claims 1 to 16 wherein the hydraulic cement is selected from the group consisting of a Portland cement, an off-white cement, oa a white cement, a high alumina cement, a slag cement, a flyash cement, a cement fondu, a gypsum cement and mixtures of the foregoing.

18. A composition according to any one of claims 1 to 17 wherein the hydraulic cement is a Portland cement.

19. A composition according to any one of claims 1 to 18 wherein the hydrocarbon binder is a bituminous binder, a tar, a pitch or a wax.

20. A composition according to claim 19 wherein the hydrocarbon binder is a bituminous binder.

21. A composition according to claim 20 wherein the bituminous binder is selected from the group consisting of bitumen, asphalt, asphaltites, asphaltic pyrobitumens, mineral waxes and mixtures of the foregoing.

22. A composition according to any one of claims 1 to 21 wherein the at least one organic solvent is an oil or a liquid petroleum derivate.

23. A composition according to claim 22 wherein the at least one organic solvent is selected from the group consisting of kerosene, diesel oil, light fuel oil, turpentine, and white spirit.

24. A composition according to claim 23 wherein the organic solvent is or contains kerosene. A composition as defined in any one of claims 1 to 24 further comprising water in a sufficient amount to cause the composition to set.

26. A composition according to claim 25 wherein the composition is a paint or render.

27. A coating or render composition comprising a composition as defined in any one of claims 1 to

28. A cementitious or concrete product formed from a composition as defined in any one of claims 1 to

29. A cementitious or concrete product according to claim 28 wherein the product is a paving brick, paving block, or a cementitious or concrete slab. -21- A method of preparing a cementitious composition in the form of a substantially free flowing powder comprising mixing a hydrocarbon binder with a hydraulic cement and at least one organic solvent to disperse said binder and the solvent essentially throughout the cement, said hydrocarbon binder being substantially solid or semi-solid at ambient temperature, wherein the composition contains a combined volume of the hydrocarbon binder and organic solvent in a range of from about 0.50 to about 20 litres per 100 kg of the hydraulic cement, and the composition is settable by hydration of the cement with sufficient water.

31. A method according to claim 30 further comprising adding water to the mixture resulting from said mixing and causing the water to hydrate the hydraulic cement sufficiently to initiate the setting of the hydraulic cement and thereby the cementitious composition.

32. A method according to claim 31 wherein the hydrocarbon binder is substantially dissolved in the organic solvent prior to the hydrocarbon binder and the organic solvent being added to the hydraulic cement. S33. A method according to claim 32 wherein the hydrocarbon binder and the organic solvent are mixed into the hydraulic cement to obtain a cementitious mixture and the method further comprises: adding water to the mixture; and mixing the water sufficiently into the mixture for causing the hydraulic cement and S"thereby the cementitious composition, to set.

34. A method according to any one of claims 30 to 33 further comprising the steps of adding one or more fillers and/or texturing agents to the hydraulic cement and mixing said agents and the hydraulic cement together. -22- A method according to claim 32 or 33 further comprising the step of adding one or more fillers and/or texturing agents to the hydraulic cement and mixing said agents and the hydraulic cement together prior to adding the hydrocarbon binder and the organic solvent to the hydraulic cement.

36. A method according to any one of claims 30 to 35 wherein the hydraulic cement is selected from the group consisting of a Portland cement, an off-white cement, a white cement, a high alumina cement, a slag cement, a flyash cement a cement fondu, a gypsum cement and mixtures of the foregoing.

37. A method according to claim 36 wherein the hydraulic cement is a Portland cement.

38. A method according to any one of claims 30 to 37 wherein the hydrocarbon binder is a bituminous binder.

39. A method according to claim 38 wherein the bituminous binder is selected from the group consisting the bitumen, asphalt, asphaltites, asphaltic pyrobitumens, mineral 15 waxes and mixtures of the foregoing. A method according to claim 39 wherein the bituminous binder is bitumen.

41. A method according to any one of claims 30 to 40 wherein the at least one organic solvent comprises an oil, a petroleum derivate or a mixture thereof

42. A method according to any one of claims 30 to 41 wherein the at least one organic solvent is selected from the group consisting of kerosene, diesel oil, light fuel oil, a turpentine, and white spirit.

43. A method according to claim 42 wherein the organic solvent is or contains kerosene. *.-DATED this 8th Day of May 2003 25 BALDWIN SHELSTON WATERS Attorneys for: RICHARD JOHN BRIGHT AND GUY SHAUN BRIGHT