AU2005243604A1 - Stabilising compositions and processes - Google Patents

Description

S&F Ref: 746548

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Blue Circle Southern Cement Limited, an Australian company, ACN 008 528 523, of Level 39 AMP Centre, 50 Bridge Street, Sydney, New South Wales, 2000, Australia Rohan Ashley McDowall' Spruson Ferguson St Martins Tower Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) Stabilising compositions and processes Associated Provisional Application Details: [33] Country:

AU

[31] Appl'n No(s): 2004907110 [32] Application Date: 13 Dec 2004 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845c STABILISING COMPOSITIONS AND PROCESSES

U

Field of the Invention The present invention relates to a composition for use in stabilising sand, gravel and soil. In particular, the present invention relates to a composition for use in block paving applications, clay pavers, slabs and products used for laying of paths, driveways, courtyards, forecourts, patios and other paved surfaces. The composition may also be used for the stabilization of beach sand, dune sand, golf bunker sand, garden bed sand, f 10 garden bed soil, garden bed gravel, road shoulder soil, road shoulder gravel and insecticide sand.

The present invention also relates to a process for producing a composition for use in stabilising sand, gravel and soil. In particular, the process may be used in block paving applications, clay pavers, slabs and products used for laying of paths, driveways, Is courtyards, forecourts, patios and other paved surfaces. The present invention may also be used for applications for filling gaps between sections of roads or other paved surfaces and in building and construction applications.

Background In the field of block paving, it is typical when paving an area to fill the gaps between adjacent paving blocks with dried sand. The dried sand acts to provide structural stability to the paving blocks, whilst still allowing for minor movement of the pavers (due to factors such as the shrinkage of the clay base) without creating large cracks (controlled cracking). There is, however, at least one problem associated with freely movable sand.

This problem is that freely movable sand can be displaced relatively easily from the joint between the pavers, especially when in contact with running water, high winds, or if the area is vigorously swept. The displacement of the sand from the joint leads to gaps being formed between the paving block which allows the pavers to move more readily and, in turn can lead to structural instability of the entire paved area.

It is a known process to provide a polymeric sealant after laying of the blocks to the sand between the blocks or paved paths. The process of sealing the jointing sand can help to ameliorate problems associated with sand movement, but the application of a sealant in this manner is both time consuming and expensive.

The movement of dune sand and beach sand can severely impact communities located especially in coastal regions. The sand from the dunes can cover roads and pathways making the roads and pathways hazardous to drivers and other users. In [R:\LIBZZ]746548spmi.doc:AWL particular, beach sand is often washed away during storms thereby exposing cliff faces Sto waves which in turn may lead to erosion. The present invention envisages mixing O sections of the dune or beach sand with low concentrations of a polymer binder to seek to alleviate problems associated with moving sand whilst retaining the look of the natural s environment.

Accordingly, it is an object of the present invention to provide a composition or process, which overcomes or substantially ameliorates at least one of the disadvantages or O problems discussed above or provides an alternative to the prior art.

Summary of the Invention According to a first embodiment of the present invention, there is provided a composition for use in gap filling applications comprising: a filler; a polymer binder; a cementitious binder; and a partly water soluble polysaccharide.

The gap filling applications may be filling gaps between pavers including block pavers, wall tiles, floor tiles; slabs and products used for laying of paths, driveways, courtyards, forecourts, patios and other paved surfaces. The gap filling applications may also include gaps in surfaces such as walls, floors, roads, and the like.

According to a second embodiment of the present invention, there is provided a process for producing a composition for use in gap filling applications comprising the steps of S mixing a polymer binder with a partly water soluble polysaccharide and a cementitious binder to form a composition; and admixing the composition of the polymer binder, the partly water soluble polysaccharide and the cementitious binder with a filler.

According to a third embodiment of the present invention, there is provided a composition produced by the process according to the second embodiment of the present invention.

According to a fourth embodiment of the present invention, there is provided a process for producing a composition for use in gap filling applications comprising combining the four components of the first embodiment of the present invention in a single step.

According to a fifth embodiment of the present invention, there is provided a composition for use in gap filling applications comprising: [R:\LIBZZ]746548speci.doc:AWL a sand or silicate containing material; S(b) polyvinyl alcohol; (N,4 U a cementitious binder; and sodium alginate.

According to a sixth embodiment of the present invention, there is provided a process of stabilizing gaps or the like, comprising the step of filling the gaps with a composition as described in the first, third or fifth embodiment of the present invention.

SAccording to a seventh embodiment of the present invention, there is provided a composition for use in gap filling applications comprising: io a clay or sandy clay material; polyvinyl alcohol; a cementitious binder; and sodium alginate.

According to an eighth embodiment of the present invention, there is provided a concentrate for admixing with a filler comprising: a polymer binder; a cementitious binder; and a partly water soluble polysaccharide.

According to a ninth embodiment of the present invention, there is provided a concentrate for admixing with a filler comprising: polyvinyl alcohol; a cementitious binder; and sodium alginate.

According to a tenth embodiment of the present invention, there is provided a process of stabilising paving blocks or the like comprising a plurality of blocks laid adjacent to each other with gaps therebetween, wherein the gaps are filled with a composition as described in the first, fourth, fifth, seventh, eighth or ninth embodiment of the present invention, and wherein water is applied to the composition towards the upper surfaces of the blocks.

Description of the Invention The words "paving blocks or the like" are intended to include block paved roads, driveways and other paved surfaces, clay pavers, slabs and any other products used in respect of the laying of paths, roads, driveways, forecourts, patios, airport runways, bus runways, truck runways, heavy machinery runways, vehicle runways and other paved surfaces.

[R:\LIBZZ]746548speci.doc:AWL t Throughout the description and claims of this specification, the words S"comprise" and "contain" and variations of the words, for example "comprising" and U "comprises", mean "including but not limited to", and are not intended to (and do not) exclude other components, integers, moieties, additives or steps.

The partly water-soluble polysaccharide used in the composition and process of the present invention dissolves slowly in water, forming a viscous solution and is typically insoluble in ethanol and ether. The partly water-soluble polysaccharide may be ,O an alginate, diutan gum, xantham gum, wellan gum, and gellan gum combinations thereof. A preferred partly water-soluble polysaccharide is sodium alginate. A io combination of diutan gum and sodium alginate may also be used.

The composition of the present invention may include a filler for use in block paving applications and the like. The filler may be selected from the group consisting of sand, a silicate containing material, crusher dust, dried kiln sand, beach sand, gravel, aggregate, limestone, granite, clay and soil. The filler may also include sand and a binder is material.

The filler of the present invention is preferably dry and may be selected from one or a combination of the following: S dry sand S dry beach sand dry crusher dust S dry clays S dry gravel; S dry aggregate material; and S dry soil.

The sand or silicate containing material may be dried sand or silicate containing material. The dried sand or silicates may be kiln dried, and the water-soluble polymer binder may be dispersed throughout the dried sand or silicates as a fine powdered or granulated formulation.

Some examples of the (dry) filler may be selected from one or more of the following: 1. dry sand; 2. beach sand; 3. gravel; 4. aggregate material; and 5. soil.

[R:\LIBZZ] 746548speci.doc: AWL The aggregate material that may be utilised for use with the compositions and Sprocesses of the present invention include sand, grinds of stone (crusher dust), porcelain, 0 glass including crushed glass, or crushed concrete.

The filler of the present invention may be sand preferably dry sand. The sand c 5 which may be used in the composition may be of a size as set out in the following table and is sand considered suitable for jointing between pavers: Standard specifications are: a washed sand of the size range seen in the following Table I.

I to Table I: Sand Grading Sieve Size 2380g1m 1181im 600 pm 300pm 150pm Jointing Sand (Min) 100.00 75.00 50.00 20.00 5.00 0.00 Jointing Sand (Max) 100.00 95.00 80.00 45.00 15.00 5.00 Sands of sizes outside this range may also be used for the composition of the present invention but they are less suitable for jointing purposes.

In another embodiment, the filler may be a sand or silicate containing material.

The sand or silicate containing material may include from about 2 to about 10wt% of the polymer binder, cementitious binder and partly water soluble polysaccharide. The polymer binder, cementitious binder and partly water soluble polysaccharide may also be present in an amount of about 2.5 to about 9.5 wt%, about 3.0 to about 9.0wt%, about to about 8.5wt%, about 4.0 to about 8.0 wt%, about 4.5 to about 7.5wt%, about 5.0 to about In order to minimize the requirement of the polymer adhesive (the cementitious binder, the polymer binder and the polysaccharide) the filler may typically conform to the grading seen in Table II.

Table II: Gradin Sieve Size 2380p1m 1181.m 6001m 300pm 150pm Minimum 100.00 75.00 50.00 20.00 5.00 0.00 Maximum 100.00 95.00 80.00 45.00 15.00 5.00 [R:\L1BZZ]746548speci.doc:AWL 6 Fillers of sizes outside this range may also be used but may require increased dose Srates of the binders and/or will show inferior characteristics to compositions containing O fillers with the above-mentioned sizes.

The composition of the present invention may also include a polymer binder c 5 which may be a water-soluble polymer. The amount of polymer binder in the composition of the present invention may include from about 0.1% to about 10%, about S0.1 to about about 0.1 to about about 0.2 to about about 0.2 to about O about 0.2 to about about 0.3 to about about 0.3 to about about S0.4 to about about 0.4 to about about 0.4 to about about 0.5 to about about 0.5 to about about 1.0 to about about 1.0 to about about 01.0 to about about 1.0 to about about 1.0 to about about 1.0 to about about 1.0 to about about 1.2 to about and about 1.5% by weight watersoluble polymer when the filler is present in the composition.

The polymer binder may be present in a concentrate (being a mixture of polymer is binder, cementitious binder and partly water soluble polysaccharide) which does not contain a filler in an amount of about 20 to about 80wt%, about 30 to about 80wt%, 40 to about 80wt% polymer. The polymer binder may also be in the amount of about 45 to about 75wt%, about 50 to about 75wt%, about 55 to about 70wt%, about 60 to about and about 60wt% to about The polymer binder in the composition of the present invention may be selected from one or more of the following polymers: 0 Polyvinyl acetate 0 Polyvinyl chloride 0 Polystyrene 0 Polybutadiene 0 Polymethylmethacrylate 0 Styrene-dimethyl maleate copolymer 0 Styrene-dimethyl fumarate copolymer 0 Styrene-butadiene copolymer Styrene Acrylic 0 Butadiene-maleic anhydride copolymer O Methylmethacrylate-acrylic acid copolymer 0 Ethyl acrylate-methacrylic acid copolymer 0 Ethyl acrylate-acrylic acid copolymer O Vinyl chloride-ethyl acrylate copolymer [R:\LIBZZ]746548speci.doc:AWL 0 l Vinyl chloride-acrylic acid copolymer SE Styrene-diethyl maleate copolymer O Vinyl chloride-butacrylate copolymer 0 Methylmethacrylate-ethacrylate copolymer 0 Styrene-ethyl acrylate copolymer 0 Vinyl chloride-2-ethylhexyl acrylate copolymer 0 Vinyl acetate-dioctyl fumarate copolymer \O 0 Acrylonitrile-butadiene copolymer 0 Vinyl acetate-diethyl maleate copolymer SThe polymer binder of the present invention may be polyvinyl alcohol (PVA). The polyvinyl alcohol (PVA) is the bonding agent or adhesive.

The degree of saponification (hydrolysis) used for the polymer binder of the present invention may be 87-90%, although other degrees of saponification also bond is effectively for the composition of the present invention.

Examples of suitable PVAs which may be used in the present invention is as listed in the following table.

Product Name Manufacturer's Name Gohsesnol GM 14 Nippon Gohsei BP 17 APS Chemicals Povial Redox Chemicals The polymer binder may also be a synthetic polymer selected from at least one of the following polymers.

vinyl polymers polyvinyl alcohol saponificated, partially saponificated and intermediate saponificated modified polyvinyl alcohol polyethylene oxide The polymer binder present in the composition of the present invention may also include any combination of the following polymers: Polymer Latexes Elastomeric Latexes [R:\LIBZZ746548speci.doc:AWL S* Natural Rubber latexes

O

0 Synthetic Rubber latexes Styrene-butadiene rubber S s Polychloroprene rubber Acrylonitrile-butadiene Rubber Thermoplastic Latexes

O

Polyacrylic Esters O Poly (ethylene-vinyl acetate) (EVA) o 0 Poly (vinylidine chloride-vinyl chloride) (PVDC) 0 Polyvinyl acetate (PVAc) O Polyvinyl propionate (PVP) O Polypropylene Thermosetting Latexes Epoxy (EP) Bituminous Latexes Asphalt Rubberized Asphalt Paraffin Mixed Latexes Natural Polymers Starch Natural Gums Plant Protein Semisynthetic Polymers Starch Decomposed Starch A-Starch Starch Derivative Cellulose Ethers O Hydroxy propyl methyl cellulose (HPMC) O Hydroxy ethyl cellulose (HEC) 0 Hydroxy methyl cellulose (HMC) O Hydroxy propyl cellulose (HPC) [R:\LIBZZ746548speci.doc:AWL 9 SA use or method of applying the composition of the present invention is for Sjointing between pavers, typically block pavers. In this use or method, the composition is U placed dry between the pavers, the area to be paved is wet and the water is allowed to soak into the composition of the present invention. The composition is then allowed to s dry out. In this use or method, the step of premixing the water with the composition of the present invention is not required. In many applications and situations, especially in respect of block paving, the handling and placement of a dry jointing composition is O considerably faster and less messy than the placement of a wet composition.

In another embodiment of the invention, the composition of the present invention allows water to move or pass through the sand on initial contact with water. Then, after about 10 to about 20 minutes, typically about 15 minutes, the bonded sand will have gelled to a point where further movement of water through the sand will not be allowed by the bonded filler. The bond is relatively weak through the composition of the present invention but is strong enough to resist most moving water.

The next step is to allow the bonded filler to dehydrate. The dehydration of the bonded filler may take a number of weeks but is dependent on the environmental conditions and placement of the bonded filler. Once dry the bonded filler will be firmly bonded and substantially insoluble.

It is believed by the applicant that the polymer binder, cementitious binder and partly water-soluble polysaccharide react with water but operate in different but complementary ways. Upon addition of water to the composition, the partly water soluble polysaccharide both thickens upon exposure to water and then cross links to hold the filler in place in the composition of the present invention. The polymer binder also begins the process of bonding to itself and to the other components, whilst the cementitious binder starts to grow interlocking crystals.

It is believed by the applicant that the polymer binder, cementitious binder and partly water-soluble polysaccharide begin to interact with each other with time. The polymer binder coats the partly water-soluble polysaccharide and increases the thickening properties thereof. Once the composition of the present invention begins to dry, the polymer binder adheres the alginate strands to the sand particles and thus assists the composition of the present invention to bind together.

One of the products of the reaction between the cementitious binder and water are Ca 2 ions. The Ca 2 ions react with the partly water soluble polysaccharide to form an insoluble compound calcium alginate). This assists the wet bound sand to resist water.

[R:\LIBZZ]746548speci.doc:AWL The products of the reaction of water with both the polymer binder and the Scementitious binder intertwine to form a bond that is substantially insoluble, irrespective U of the usual solubility of the composition from the polymer binder.

The gel setting nature of the composition of the present invention after wetting S 5 the upper surface ensures that the sand has some level of adhesion or bonding all the way to the bottom of the composition. The gel setting nature of the composition of the present invention ensures the bonded composition is less likely to be removed out of the joint and thus provides stability to the surrounding pavers in a block paving application.

In a process of stabilizing paving blocks or the like comprising a plurality of 0to blocks laid adjacent to each other with gaps therebetween by applying a composition of the present invention to the gaps between the plurality of pavers, the composition is able to be placed dry between the blocks. The composition of the present invention is then set by soaking with water. The wetted composition of the present invention demonstrates resistance to further moisture within about 15 minutes of the initial wetting of the composition.

The "soil" as used herein may include all unconsolidated materials above bedrock or the natural medium for growth of plants and may also include a mixture of silt, gravel, and sand. Soil may also include fine materials which may be considered to be plastic material comprising substantially particles having diameters less than 0.074mm silt) and also particles having diameters less than 0.074mm clay). Such particles may be colloidal particles and thus may be considered to be loose, earthy, extremely fine grained natural sediment or soft rock characterised by high plasticity and by a considerable content of clay minerals. Clay minerals are one of a complex and loosely defined group of finely crystalline, metacolloidal or amorphous hydrous silicates of aluminium, magnesium and iron. The common clay minerals belong to the kaolin, montmorillonite (smectite) and illite groups. Different types of soil will contain varying amounts of clay. The usual amount of clay in soils envisaged for structures may be in the amount of about 0.5 to about The soils utilised in the compositions and processes of this invention may include clay type, siliceous type, crushed rock, well graded gravel, silty/ clay gravel, sand, sandy silty clays, and heavy clays. However, it should be appreciated that other soils not specified above but which would be capable of being admixed to the compositions of the present invention are included within the scope of this invention.

The cementitious binder may be selected from: 1. Portland cement; [R:\LIBZZ746548speci.doc:AWL 2. High alumina cement, Portland cement blended with fly ash, ground blast furnace Sslag, zeolite, silica fume or volcanic ash; 0 3. Alkali or Alkaline earth metal hydroxide and a pozzolan; 4. Plaster (gypsum) c 5 5. Geopolymer The alkali or alkaline earth metal hydroxide may be sodium hydroxide, j potassium hydroxide, calcium hydroxide or magnesium hydroxide. The Pozzolan may be \O selected from but is not restricted to a material such as ground blast furnace slag, fly ash, silica fume, metakaolin and zeolite.

0Preferred ranges of components The percentage ranges which may be used for the present invention is as follows: Partly water soluble polysaccharide 0.1 to 4% s1 polymer binder 0.1 to cementitious binder 0.1 to Filler 80 to 99.5% An example of the polymer binder, cementitious binder and partly water-soluble polysaccharide is polyvinyl alcohol (PVA), cement and alginate.

An example of a typical composition is as follows: 90.0 to 99.0 wt% of a dry filler; 0.30 to 7 wt% polymer binder; 0.00 to 7 wt% cementitious binder; and 0.04 to 2.0wt% partly water soluble polysaccharide.

Another example of the composition of the present invention is about 1.Owt% cementitious binder, about 1.55wt% polymer binder, about 0.45wt% partly water soluble polysaccharide and about 97% filler.

The composition of the present invention may also be as set out below: 97.0 wt% of dry sand; and 3.0% adhesive.

The adhesive may comprise as a weight percentage of the total composition: 1.55 wt% polyvinyl alcohol; 1 .Owt% cementitious material; and 0.45 wt% sodium alginate.

[R:\LIBZZ746548speci.doc:AWL 12 The composition of the present invention may also be as set out below: 98.65 wt% of dry sand; and 0 1.35% adhesive.

The adhesive may comprise as a weight percentage of the total composition: 0.7 wt% polyvinyl alcohol; S 0.5 wt% cementitious material; and 0.15 wt% sodium alginate.

SThe composition of the present invention may also be as set out below: S* 94.20 wt% of dry sand; and 5.80% adhesive.

SThe adhesive may comprise as a weight percentage of the total composition: 3.0 wt% polyvinyl alcohol; 2.0 wt% cementitious binder; and 0.80 wt% sodium alginate.

The present invention also includes a concentrate which comprises polyvinyl alcohol; cementitious binder; and sodium alginate.

The concentrate does not include the filler and is able to be transported more easily and cost effectively which is advantageous. The concentrate may be added to a suitable amount of filler after the concentrate is transported to a suitable location.

In addition, the compositions and concentrates of the present invention may also include a herbicide, a termacide and/or fungicide (for example ACTICIDE EP powder), powdered silicates (for example sodium silicate) and/or one or more colorants or dyes.

A thickener may also be added to the composition of the present invention and the thickener may include but is not limited to cellulose ethers such as hydroxyethylcellulose (HEC) and hydroxypropylmethylcellulose (HPMC).

Other additives which may be added to the composition of the present invention include the following.

calcium sulphate can be added as a source of calcium to the mixture. The calcium preferably reacts with the alginate to make the alginate insoluble.

[R:\LIBZZ]746548speci.doc:AWL 13 S sequestrants such as inorganic polyphosphates, hydroxy acids and Saminopolycarboxylic acids which may be used to delay the gel forming reaction between U the calcium ions and alginate.

the water-soluble polymer component may comprise grains or particles coated 5c with a solubilising agent, which, upon contact with water, enhances the solubility of the polymer component in the water.

S the sand may be pretreated with a polymer and coloured oxide to add colour to Sthe end product.

S powdered silicates (for example sodium silicate) and/or one or more colorants or o dyes.

Applications The composition of the present invention is preferably applied in a dry powdered or particulate form, and may thus easily be swept or otherwise applied into interstitial gaps is in block paved surfaces, between gaps between rocks or simply flattened to expose a smooth surface. The composition of the present invention does not set until water is applied and can safely be exposed to air or oxygen without setting, thus the composition is easy to store and handle. The typical shelf life is 6 to 12 months.

It is to be noted that the present invention is suitable not just for block paving applications, but for any application where blocks or slabs or the like are laid and require interstitial stabilization. The invention could also be used to stabilize beach or dune sand, gravel and soil on the shoulders of roads, golf bunker sand, or sand used in insecticide shakers.

The following description of the preferred embodiment(s) is intended only to illustrate and further describe the present invention and should not be construed as limiting the generality and scope of the claims.

Description of the Preferred Embodiment(s) The invention will now be further described by reference to the following non-limiting examples of the present invention. All weight percentages in the following examples are weight percentages unless otherwise stated.

Example 1 [R:\LIBZZ]746548speci.doc:AWL Aim: To determine the extent of water penetration into dry sand that is stabilised with a combination of components, and in an airflow constrained environment.

Method: Twelve sample mixtures were prepared with varying combinations of sand, PVA, alumina cement and sodium alginate. Each sample mixture was placed in a tube that comprised a hole located at the base of the tube. Blue dyed water was applied to the top of each sample mixture and the time taken for the water to penetrate to the bottom of the sample was recorded. The time taken for the water to penetrate through to the bottom of each sample mixture simulates the time taken for water to move to the bottom of a jointing composition .used in, for example, block paving applications.

The details of each of the twelve sample mixtures together with the time taken for the blue dyed water to move through the sample mixture is recorded in Table 1 as set out below.

Table 1: 12 Sample Mixtures arts by weiht)and time taken for water movement Mix Semi-Closed System: Time taken for Number Alumina Sodium water to move through to the bottom Sand PVA Cement Alginate of each sample(the Joint).

1 100.0 0 0 0 15 seconds 2 99.0 1 0 0 14 seconds 3 99.0 0 1 0 14 seconds 4 98.0 1 1 0 12 seconds 97.5 1 1 0.5 18 seconds 6 97.0 2 1 0 20 seconds 7 96.5 2 1 0.5 75 seconds 8 95.0 2 3 0 22 seconds Did not reach the bottom.

9 94.5 2 3 0.5 Penetrated 3.5 of 7 cm 94.0 5 1 0 24 seconds 11 93.5 5 1 0.5 30 seconds [R:\LIBZZ]746548speci.doc:AWL Did not reach the bottom.

12 96.0 2 1 1 Penetrated 3.5 of 7 cm The sand used in these examples are selected from the following specification. The standard specifications are: a washed sand of the size range seen in the following Table I.

Table A: Sand Grading Sieve Size 2380p.m 1181pm 600tpm 300pm 150pm Jointing Sand (Min) 100.00 75.00 50.00 20.00 5.00 0.00 Jointing Sand (Max) 100.00 95.00 80.00 45.00 15.00 5.00 Discussion: The results shown in Table A show that the partly water-soluble polysaccharide, sodium alginate, acts to prevent water from penetrating into the mixture. The applicant believes that sodium alginate limits water movement by expanding within the voids located between the sand particles, which thereby create a barrier to the water. The addition of fine particles such as PVA or cement provides further obstructions within the voids thereby assisting the alginate to block the interstitial spaces between the sand particles.

It was also observed that the PVA, when not combined with the alginate, tended to draw water into the mixture.

Conclusion: If an excess of sodium alginate is added to the mixture then water will be unable to penetrate through the sand. Since water is required to react with the PVA to create a bond with the sand, an excess of alginate means that the bottom of the joint will not be bound.

Example 2 Aim: [R:\LIBZZ746548speci.doc:AWL To determine the extent of water penetration into dry sand that is stabilised with a combination of components, and in an environment that is open to airflow.

Method: Twelve sample mixtures were prepared with varying combinations of sand, PVA, alumina cement and sodium alginate. Two block payers were placed on a sand base in a perspex case. A separator was used to make twelve spaces in the joint between the payers and the perspex wall. Each of the twelve spaces were filled with a different sample mixture.

Blue dyed water was applied onto the top of each sample and the time taken for the water to penetrate to the bottom of each sample mixture was recorded.

The details of each of the twelve sample mixtures together with the time taken for the blue dyed water to move through the sample mixture is set out in Table 2 below.

Table 2: 12 Sample Mixtures (parts by weight) ad time taken for water movement Mix Open System: Time taken for the Number Alumina Sodium water to move through to the bottom PVA. Cement Alginate of each sample ("the Joint").

1 100.0 0 0 0 10 seconds 2 99.0 1 0 0 10 seconds 3 99.0 0 1 0 9 seconds 4 98.0 1 1 0 8 seconds 97.5 1 1 0.5 10 seconds 6 97.0 2 1 0 8 seconds 7 96.5 2 1 10.5 8 seconds 8 95.0 2 3 0 8 seconds 9 94.5 2 3 0.5 8 seconds 94.0 5 1 0 8 seconds 1193.5 5 1 0.5 10 seconds 1296.0 2 1 1 12 seconds [R:\LIBZZ]746548speci.doc:AWL Discussion: At the dose rates used in this test series, and with the specified particle size distribution of the sand, the water easily and reasonably quickly penetrated to the bottom of the joint for all mixture samples. Mixture sample numbers 11 and 12, which had elevated levels of PVA and alginate displayed slightly slower penetration into the joint.

Conclusion All mixture sample combinations allowed water to penetrate quickly to the bottom of a 1o 5cm joint when air is able to easily move through the joint.

Example 3 Aim: To determine the ability of sand that is stabilised with a combination of components to resist water after 15 minutes curing to assess the gel setting property).

Method: Twelve sample mixtures were prepared with varying combinations of sand, PVA, alumina cement and sodium alginate. Each sample mixture was placed in a 5cm pile on a piece of paper. Water was then added to each of the sample mixtures. After 15 minutes reaction time, a drop of water was placed on top of each sample mixture. It was then observed whether or not the drop of water penetrated into the mixture.

The details of each sample mixture and the results are set out below in Table 3.

Table 3: Sample mixtures and resistance to water Mix Alumina Sodium Number Sand PVA Cement Alginate Water Penetration after 15 Minutes 1 100.0 0 0 0 Yes 2 99.0 1 0 0 Yes 3 99.0 0 1 0 Yes 4 98.0 1 1 0 Yes [R:\LBZZ 746548speci.doc: AWL 97.5 1 1 0.5 No 6 97.0 2 1 0 Yes 7 96.5 2 1 0.5 No 8 95.0 2 3 0 Yes 9 94.5 2 3 0.5 No 94.0 5 1 0 Yes 11 93.5 5 1 0.5 No 12 96.0 2 1 1 No Discussion: The results in table 3 show that sodium alginate imparts the ability of the mixture to resist water after 15 minutes curing. Neither PVA nor cement had an effect on the initial resistance of each of the sample mixtures to water.

Conclusion: Sodium alginate imparts the property of each of the sample mixtures to resist water after minutes curing.

Example 4 Aim: To determine the setting time and relative strength of sands that have been stabilised with varying combinations of components.

Method: Twelve sample mixtures were prepared with varying combinations of sand, PVA, alumina cement and sodium alginate. Each sample mixture was placed in a 5cm pile on a piece of paper. Water was then added to each of the sample mixtures and the respective sample mixtures were allowed to dry at 23 0 C and 50% humidity. After 1 and 5 days of curing, the strength of the bonding was assessed.

[R:\LIBZZ]746548speci.doc:AWL The details and results are summarised in Table 4.

Table 4: 12 Sam le Mixtures and the Setting and Strength Characteristics.

SBonding after 1 Day Bonding after 5 Days No Strength- The sand is 1 100 0 0 0 still moist No Bond Weak. Has a thin top layer and is wet Very hard. High flexural 2 99.0 1 0 0 underneath. strength.

No strength slightly 3 99.0 0 1 0 drier than I No Bond Weak. Has a thin top layer and is wet Very hard on top. It is like underneath. Slightly powder underneath. No 4 98.0 1 1 0 firmer than 2. bonded all the way through.

Quite hard. Dry. A Moderately strong. Still thick top layer. Partially weaker than 2 underneath bonded all the way to the but better than 4. Can 97.5 1 1 0.5 bottom. abrade sand off the bottom.

Quite hard. A moderate Very hard. High flexural top layer, thicker than 2 strength. Bonded through but thinner than 5. Still to bottom. Can abrade moist and so not bonded sand off the bottom. Better 6 97.0 2 1 0 under the skin, than Quite hard. A moderate top layer, thicker than 2 but thinner than 5. Still moist and so not bonded Very hard. High flexural 7 96.5 2 1 0.5 under the skin. strength. Same as 6.

[R:\LIBZZ]746548speci.doc:AWL Quite hard. Not bonded Very hard. High flexural 8 95.0 2 3 0 under the skin. strength. No better than 7.

Firm. Bonded all the Very hard. High flexural 9 94.5 2 3 0.5 way to the bottom. strength. Similar to 8 A thick but strong top The strongest bonding.

layer. Not bonded under Cannot abrade sand off the 94.0 5 1 0 the top layer. bottom.

Very hard. Bonded through to the bottom. Not as hard Is quite firm. It has a as 10 or 12. Can only thick top layer. Strongly slightly abrade sand off the 11 93.5 5 1 0.5 stuck to the paper. bottom.

Is quite firm. It has a The second strongest thick top layer. Rubbery behind 10. Cannot abrade 12 96.0 2 1 1 under the layer. sand off the bottom.

Discussion: Early Bond Strength It is observed in table 4 that adding sodium alginate to each of the sample mixtures increases the early bond strength. The sodium alginate also required a sufficient number of fines particles in the sand to allow the alginate to fill the pores between the sand particles. The alginate also provided bonding throughout the entire sample mixture.

The PVA provided a strong bond although only after the PVA had dried. Thus 1o after 1 day there was only a skin of sand bonded by the PVA. Adding an excess of PVA did not improve the performance of the material. There is a finite maximum dose rate for each additive.

Final Bond Strength After 5 days all samples containing PVA were well bonded. The PVA is the Is major strength provider for the dry cured samples. The addition of cement resulted in reduced strength under the top layer the layer exposed to the air). The alginate provided moderate strength throughout the sample mixture.

Conclusion: The PVA is the major contributor to the dry cured strength of the sample mixtures. The cement tends to create a top layer with increased strength and a lower layer [R:\LIBZZ746548speci.doc:AWL n with reduced strength. The cement takes little part in the final dry cured strength.

SThe alginate improves the early strength of the mixture and provides moderate to low O final strength throughout the sample mixture.

e¢ mc [R:\LIBZZ746548speci.doc:AWL Example 5 Bonding Underwater Aim: To determine whether sand that have been stabilised with varying combinations of components can become bound when cured underwater.

Method: Twelve sample mixtures were prepared with varying combinations of sand, PVA, alumina cement and sodium alginate. Each sample mixture was placed in a 5cm pile on a piece of paper. Water was then added to each of the sample mixtures and the sample mixtures were then placed into a container. The container was immediately filled with water and the sample mixtures allowed to cure for 5 days. The samples were then removed from the water and their bonding properties measured. After a further 5 days of curing at humidity, the bond strengths of each of the sample mixtures were re-measured.

The details and results of each sample mixture are summarised below in Table Table 5: 12 Sample Mixtures and Bonding Characteristics.

SE Curing Underwater S Bond Strength after z .a Bond Strength while being moved and Underwater allowed to dry 1 100 0 0 0 No strength No strength Very little strength. A little bit stuck to the 2 99.0 1 0 0 No strength paper.

No strength though has 3 99.0 0 1 0 a crust on top No strength No strength. A few 4 98.0 1 1 0 No strength minor clumps A solid patty. 2nd in 97.5 1 1 0.5 strength to 12 Solid. In good condition [H:Patent 673232 05-11-04.doc:AWL In clumps but very little 6 97.0 2 1 0 No strength strength A solid patty. 4th in 7 96.5 2 1 0.5 strength. Solid. In good condition Not as good as 5, 7,9,11 or 12. Was weak on top Some stuck to paper, the 8 95.0 2 3 0 but stronger underneath. rest had no strength A solid patty. 3rd in 9 94.5 2 3 0.5 strength Solid. In good condition Solid. Stuck together in 94.0 5 1 0 No strength its new shape A solid patty though 11 93.5 5 1 0.5 quite weak. Solid. In good condition By far the strongest 12 96.0 2 1 1 patty. Solid. In good condition Discussion: Bond Strength While Curing Underwater It can be seen in table 5 that only the samples that contained alginate were bonded while curing underwater. It can also be seen that the strength of the bond is partly dependant on the ratio of the amount of PVA to alginate. As the ratio of PVA to alginate is increased, the strength of the underwater alginate bond decreases. The reason for this is that the PVA begins to interfere with the thickening property of the alginate as PVA interlocks with itself.

The cement produces a very weak crust on top of the mixture.

Bond Strength of Samples Cured Underwater and then Dried Out.

The PVA is water-soluble. While curing underwater it has a tendency to leach out of the joint and into the surrounding water. Thus those sample mixtures containing PVA or PVA and cement had little strength.

The presence of alginate is again the major factor in ensuring that the sample mixture retains its ability to gain strength. The applicant believe that the alginate [H:]Patent 673232 05-11-04.doc:AWL achieves this by thickening and thus locking the PVA in the joint ensuring that after drying the PVA is still present to create a strong dry bond.

SOther than its effect as a filler, the cement has little effect on the strength of the sample while curing underwater.

Conclusion: The alginate is the major contributor to strength of the mixture while it is curing 0 underwater. The PVA tends to leach out of the sample and the cement is not at a high Cc enough concentration to be effective.

In S o0 Example 6 Rate of Drying and Insolubility

O

Aim: To determine the rate of drying and insolubility in water of sands that have been stabilised 1i with varying combinations of components.

Method: Twelve sample mixtures were prepared with varying combinations of sand, PVA, alumina cement and sodium alginate. Each sample mixture was placed in a 5cm pile on a piece of paper. Water was then added to each of the sample mixtures and the sample mixtures were allowed to dry over two days. The extent of drying was measured by monitoring the moisture mark on the paper under each of the sample mixtures. The sample mixtures were then allowed to dry for a further 3 days. After drying the sample mixtures for a total of 5 days, the sample mixtures were placed into a container and submerged underwater.

After 2 days underwater the bonding of the sample mixtures under water were measured.

Results: The details of each sample mixture and results are summarized below in Table 6.

Table 6: 12 Sample Mixtures and Rate of Drying and Insolubility.

L Drying Time Sa Size of the z a Moisture Mark En o (cm) Insolubility after drying (H:]Pment 673232 05-11-04.doc:AWL 1 100 0 0 0 0- (Dry) Fully Soluble 2 99.0 1 0 0 0 Fully Soluble Fully Soluble, though minor 3 99.0 0 1 0 0 bonding on top Fully Soluble though held 4 98.0 1 1 0 0 together. Did not collapse 97.5 1 1 0.5 1 Insoluble but not very strong 6 97.0 2 1 0 1 Insoluble but not very strong 7 96.5 2 1 0.5 2.5 Insoluble and strong Semi soluble. Weak around the 8 95.0 2 3 0 1 edges 9 94.5 2 3 0.5 2.5 Insoluble and strong Semi soluble. Weak around the 94.0 5 1 0 3 edges 11 93.5 5 1 0.5 3.5 Insoluble and strong 12 96.0 2 1 1 2.5 Insoluble and very strong the faster the drying the smaller the moisture mark.

Discussion: s Rate Of Drying It is observed that both PVA and alginate slow the rate of drying. The addition of more PVA and alginate to the sample mixtures results in a slower rate of drying. The addition of cement to the sample mixtures does not either increase or decrease the rate of drying (see sample no.6 and 8).

Insolubility of Dry Cured Samples The addition of PVA alone does not make an insoluble bond. However, the addition of cement to the PVA will produce an insoluble bond. If the ratio of PVA to cement is greater than about 3:1 then it is observed that the cement is not able to make the PVA insoluble.

The addition of alginate also makes the bond insoluble. It is observed that increasing the dose rate of the alginate increases the sample mixture resistance to water.

Conclusion: IH:]Paicnt 673232 03-II.04,doc:AWL The addition of PVA and alginate to the sample mixture increases the time taken for the Ssample mixture to dry out. The addition of cement does not either increase or reduce the Sdrying time of the sample mixtures. The addition of cement to the PVA makes it Cc insoluble. The alginate also imparts water resistance to each of the sample mixtures.

Advantages of the Composition The advantages of the compositions and processes of the present invention include at least Cc one or more of the following: N the ability to place a dry product provides the following benefits to the end user.

fast placement via brushing the dry product into all crevices and into the required C shape.

easy cleaning due to a lack of sticky paste.

The composition of the present invention provides a gel setting property when the composition is used as a jointing compound. The gel setting property provides an advantage that if the composition of the present invention is exposed to rain soon after placement into a joint or gap then the composition of the present invention will be less likely to be washed away from the gap or crevice between the pavers. The gel setting property also provides the composition of the present invention with at least a minimum level of bonding throughout the entire jointing compound, irrespective of whether the composition has had suitable time to dry.

The dry, firm setting of the composition provides further strength ensuring that the composition is even less likely to be moved from its intended position.

The insolubility of the composition after the composition has dried out ensures that rain will be even less likely to remove the composition from its intended position.

The flexibility in the number of dry fillers that can be used in the invention gives it the versatility to be used in many circumstances.

Modifications and variations such as would be apparent to a skilled person are deemed to be within the scope of the present invention. It is also to be understood that the present invention should not be limited to the particular embodiment(s) described above.

[H:jPatent-673232 -05-II-04.doc:AWL

Claims (24)

1. A composition for use in gap filling applications comprising: a) a filler; b) a polymer binder; c) a cementitious binder; and d) a partly water soluble polysaccharide.

2. A composition according to claim 1, wherein the filler is selected from the group Cconsisting of sand, a silicate containing material, beach sand, clay, gravel, aggregate and C1 soil.

3. A composition according to claim 1 or 2, wherein the filler is sand or a silicate N containing material.

4. A composition according to claim 3, wherein the filler is sand. A composition according to any one of claims 1 to 4, wherein the polymer binder is selected from the group consisting of water soluble polymers, elastomeric latex is polymers, thermoplastic latex polymers, bituminous latex polymers, mixed latex polymers, natural polymers and semisynthetic polymers.

6. A composition according to any one of claims 1 to 5, wherein the polymer binder is selected from the group consisting of polyvinyl alcohol, polyvinyl acetate, poly vinyl chloride, polystyrene, polybutadiene, polymethylmethacrylate, styrene-dimethyl maleate copolymer, styrene-dimethyl fumarate copolymer, styrene-butadiene copolymer, butadiene-maleic anhydride copolymer, methylmethacrylate-acrylic acid copolymer, ethyl acrylate-methacrylic acid copolymer, ethylacrylate-acrylic acid copolymer, vinyl chloride-ethylacrylate copolymer, vinyl chloride-acrylic acid copolymer, styrene-diethyl maleate copolymer, vinyl chloride-butacrylate copolymer, methylmethacrylate- ethacrylate copolymer, styrene-ethylacrylate copolymer, vinyl chloride-2-ethylhexyl acrylate copolymer, vinyl acetate-dioctyl fumarate copolymer, acrylonitrile-butadiene copolymer and vinyl acetate-diethyl maleate copolymer.

7. A composition according to claim 6, wherein the polymer binder is a polyvinyl family polymer.

8. A composition according to claim 7, wherein the polymer binder is polyvinyl alcohol.

9. A composition according to any one of claims 1 to 8, wherein the polysaccharide is an alginate. A composition according to claim 9, wherein the alginate is sodium alginate. [H:]Paent 673232 05-I -04.doc:AWL 0 11. A composition according to any one of claims 1 to 10, wherein the cementitious binder is selected from the group consisting of Portland cement and high alumina cement. S12. A composition according to claim 11, wherein the cementitious binder is blended c with a pozzolan or gypsum.

13. A composition according to claim 12, wherein the pozzolan is selected from the group consisting of fly ash, ground blast furnace slag, zeolite, silica fume, perlite and Svolcanic ash. 0 14. A composition according to any one of claims 1 to 13, wherein the composition C further comprises a member selected from the group consisting of a fungicide, a termacide, a herbicide and a mixture thereof. CI 15. A composition for use in gap filling applications comprising: a sand or silicate containing material; polyvinyl alcohol; a cementitious binder; and sodium alginate.

16. A composition for use in gap filling applications or block paving applications substantially as herein before described with reference to the examples.

17. A process for producing a composition for use in gap filling applications comprising the steps of mixing a polymer binder and a partly water soluble polysaccharide and a cementitious binder to form a composition; and S admixing the composition of the polymer binder, the partly water soluble polysaccharide and the cementitious binder with a filler.

18. A process according to claim 17, wherein the binder is polyvinyl alcohol.

19. A process according to claim 17 or 18, wherein the partly water soluble polysaccharide is an alginate. A process according to claim 17, 18 or 19, wherein the alginate is sodium alginate.

21. A process according to any one of claims 17 to 20, wherein the cementitious binder is selected from the group consisting of Portland cement and high alumina cement.

22. A process for producing a composition for use in gap filling applications comprising the steps substantially as hereinbefore described with reference to any one of the examples.

23. A process of stabilizing paving blocks or the like comprising a plurality of blocks laid adjacent to each other with gaps therebetween, comprising the step of filling 1H:1Paent- 673232- 05-II-04.doc:AWL 29 0 the gaps between the plurality of blocks with a composition as described in any one of claims 1 to 16.

24. A process of filling gaps between a plurality of blocks, comprising the step of c filling the gaps between the plurality of blocks with a composition as described in any one s of claims 1 to 16. A composition produced by the process according to any one of claims 17 to 22.

26. A concentrate for admixing with a filler comprising: 2C a polymer binder; C, a cementitious binder; and 0 10 a partly water soluble polysaccharide. C1 27. A concentrate according to claim 26, wherein the filler is selected from the group consisting of sand, a silicate containing material, beach sand, clay, gravel, aggregate and soil.

28. A concentrate according to claim 26 or 27, wherein the polymer binder is is selected from the group consisting of polyvinyl alcohol, polyvinyl acetate, poly vinyl chloride, polystyrene, polybutadiene, polymethylmethacrylate, styrene-dimethyl maleate copolymer, styrene-dimethyl fumarate copolymer, styrene-butadiene copolymer, butadiene-maleic anhydride copolymer, methylmethacrylate-acrylic acid copolymer, ethyl acrylate-methacrylic acid copolymer, ethylacrylate-acrylic acid copolymer, vinyl chloride-ethylacrylate copolymer, vinyl chloride-acrylic acid copolymer, styrene-diethyl maleate copolymer, vinyl chloride-butacrylate copolymer, methylmethacrylate- ethacrylate copolymer, styrene-ethylacrylate copolymer, vinyl chloride-2-ethylhexyl acrylate copolymer, vinyl acetate-dioctyl fumarate copolymer, acrylonitrile-butadiene copolymer and vinyl acetate-diethyl maleate copolymer.

29. A concentrate according to claim 26, 27 or 28, wherein the polymer binder is a polyvinyl family polymer. A concentrate according to claim 29, wherein the polymer binder is polyvinyl alcohol.

31. A concentrate according to any one of claims 26 to 30, wherein the partly water soluble polysaccharide is alginate.

32. A concentrate according to claim 31, wherein the alginate is sodium alginate.

33. A concentrate for admixing with a filler substantially as hereinbefore described with reference to any one of the examples.

34. A process for producing a concentrate comprising the steps substantially as hereinbefore described with reference to any one of the examples. [H:]Patent- 673232 05-11-04.doc:AWL Dated 13 December, 2005 Blue Circle Southern Cement Limited Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [H:]Patent -673232 OS-I I-04.doc:AWL