WO2000014027A1

WO2000014027A1 - A cementitious composition for inhibiting the formation of efflorescence

Info

Publication number: WO2000014027A1
Application number: PCT/AU1999/000720
Authority: WO
Inventors: Richard John Bright; Guy Shaun Bright
Original assignee: Richard John Bright; Guy Shaun Bright
Priority date: 1998-09-03
Filing date: 1999-09-03
Publication date: 2000-03-16

Abstract

There is disclosed a cementitious composition comprising a hydraulic cement, and a hydrocarbon binder mixed in at least one organic solvent which mixture is dispersed essentially throughout the cement. The hydrocarbon binder is substantially solid or semi-solid at ambient temperature and the composition is setable by hydration of the hydraulic cement with sufficient water. There is also disclosed a method of preparing the composition as well as cementitious or concrete items made from the composition.

Description

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. 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 after 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 described 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 an aspect of the invention there is provided a cementitious composition

comprising a hydraulic cement, and a hydrocarbon binder mixed in at least one

organic solvent and dispersed essentially throughout the cement, wherein the

hydrocarbon binder is substantially solid or semi-solid at ambient temperature and the

composition is setable by hydration of the hydraulic 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 still a further aspect of the invention there is provided a method of

preparing a cementitious composition comprising the step of 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, wherein the hydrocarbon binder is

substantially a solid or semi-solid at ambient temperature and the composition is

setable by hydration of the cement with sufficient water.

Preferably, the hydrocarbon binder will be mixed with the organic solvent

prior 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 throughout the cement. The mixing of the components of the cementitious composition 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. 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.

The 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 such 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 consistency 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. 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-in-

oil 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 a 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

added 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. 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

45%o 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 3.5% 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. 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

Sufficient 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 (PNC) 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 hours 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 5

A conventional cementitious mixture consisting of approximately 5% to 10%

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 in-

situ, 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 10% 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 3.5%

Total 100.00% 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 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 3.5%

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

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

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS :-

1. A cementitious composition comprising a hydraulic cement, and a

hydrocarbon binder mixed in at least one organic solvent and dispersed

essentially throughout the cement, wherein the hydrocarbon binder is

substantially solid or semi-solid at ambient temperature and the composition is

setable 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.

5. A composition according to any one of claims 1 to 4 wherein the composition

contains a combined volume of the hydrocarbon binder and the organic solvent

in a range of from about 0.50 litres to about 20 litres per 100 kg of the

hydraulic cement.

6. A composition according to claim 5 wherein the combined volume of the

hydrocarbon binder and the organic solvent is in a range of from about 1 litre

to about 10 litres.

7. A composition according to claim 6 wherein the combined volume of the

hydrocarbon binder and the organic solvent is in a range of from 2 litres to 6

litres.

8. A composition according to any one of claims 5 to 7 further comprising one or

more fillers and/or texturing agents.

9. A composition according to claim 8 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.

10. A composition according to claim 9 wherein the additional volume of the

hydrocarbon binder and the organic solvent is between 0.4 litres and 50 litres.

11. A composition according to claim 10 wherein the additional volume of the

hydrocarbon binder and the organic solvent is between 0.5 and 3.0 litres.

12. A composition according to any one of claims 1 to 4 further comprising one or

more fillers and/or texturing agents.

13. A composition according to any one of claims 8 to 12 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.

14. A composition according to claim 13 wherein the weight ratio of the hydraulic

cement to the fillers and/or texturing agents is between 1 : 1 and 1 :3.

15. A composition according to claim 13 wherein the weight ratio of the hydraulic

cement to the fillers and/or texturing agents is between about 1 :3 and 1:6.

16. A composition according to claim 13 wherein the weight ration of the

hydraulic cement to the fillers and/or texturing agents is between about 1 :6 and

1 :25.

17. A composition according to any one of claims 8 to 16 wherein the fillers

and/or aggregates are selected from the group consisting of sand, gravel, slag,

stones, rocks and minerals.

18. A composition according to any one of claims 1 to 17 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.

19. A composition according to any one of claims 1 to 18 wherein the hydraulic

cement is a Portland cement.

20. A composition according to any one of claims 1 to 19 wherein the hydrocarbon

binder is a bituminous binder, a tar, a pitch or a wax.

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

bituminous binder.

22. A composition according to claim 21 wherein the bituminous binder is selected

from the group consisting of bitumen, asphalt, asphaltites, asphaltic

pyrobitumens, mineral waxes and mixtures of the foregoing.

23. A composition according to any one of claims 1 to 22 wherein the at least one

organic solvent is an oil or a liquid petroleum derivate.

24. A composition according to claim 23 wherein the at least one organic solvent

is selected from the group consisting of kerosene, diesel oil, light fuel oil,

turpentine, and white spirit.

25. A composition according to claim 24 wherein the organic solvent is or contains

kerosene.

26. A composition as defined in any one of claims 1 to 25 further comprising

water in a sufficient amount to cause the composition to set.

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

render.

28. A coating or render composition comprising a composition as defined in any

one of claims 1 to 26.

29. A cementitious or concrete product formed from a composition as defined in

any one of claims 1 to 26.

30. A cementitious or concrete product according to claim 29 wherein the product

is a paving brick, paving block, or a cementitious or concrete slab.

31. A method of preparing a cementitious composition 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, wherein

the hydrocarbon binder is substantially solid or semi-solid at ambient

temperature and the composition is setable by hydration of the cement with

sufficient water.

32. A method according to claim 31 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.

33. 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.

34. A method according to claim 33 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 thereby the cementitious composition, to set.

35. A method according to any one of claims 31 to 34 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.

36. A method according to claim 33 or 34 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.

37. A method according to any one of claims 31 to 36 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.

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

cement.

39. A method according to any one of claims 31 to 38 wherein the hydrocarbon

binder is a bituminous binder.

40. A method according to claim 39 wherein the bituminous binder is selected

from the group consisting the bitumen, asphalt, asphaltites, asphaltic

pyrobitumens, mineral waxes and mixtures of the foregoing.

41. A method according to claim 40 wherein the bituminous binder is bitumen.

42. A method according to any one of claims 31 to 41 wherein the at least one

organic solvent comprises an oil, a petroleum derivate or a mixture thereof.

43. A method according to any one of claims 31 to 42 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.

44. A method according to claim 43 wherein the organic solvent is or contains

kerosene.