AU2018282324A1 - Compositions for binding aggregate - Google Patents

Abstract

Disclosed herein is a composition for binding aggregate. The composition comprises reactive precursors which, when mixed, react to solidify. Following mixing of the reactive precursors, the composition has a viscosity such that, when poured onto aggregate that has been pre-arranged to define a road base, the composition percolates through the aggregate whilst reacting, whereby a road incorporating the aggregate is formed without mechanical mixing. Also disclosed are compositions especially useful in underground environments.

Description

COMPOSITIONS FOR BINDING AGGREGATE

Technical Field

[0001] The present invention relates to compositions for binding aggregate and to compositions for use in an underground environment. In a specific application, the compositions may be used to form road surfaces in underground environments.

Background Art

[0002] Aggregate used in the construction industry typically includes coarse to medium grained particulate material such as sand, gravel, crushed stone, etc. Aggregates are used extensively in composite materials such as concrete, and help to reinforce and add bulk strength to the resultant composite material. Aggregates may also be used as base material under foundations, roads, and railroads in order to provide a stable foundation or road base.

[0003] Aggregates are most commonly used with cementitious materials in order to produce concrete, which is an extremely useful product for many construction applications. However, concrete may not be suitable in some applications (e.g. where mixing and pouring concrete may be difficult, or where concrete would be slow to set), and a number of non-cementitious compositions for binding aggregate are known. For example, non-cementitious bonding agents that bind particulate materials together for road or pavement building are known. However, such agents require the particulate materials and applied bonding agent to undergo agitation and mechanical mixing in order for them to be thoroughly mixed. Alternatively or in addition, such agents may require the use of high pressure equipment to apply the bonding agents (which, in effect, mechanically mixes the agents and aggregate). Such application techniques may not be practical or safely achievable in some locations, for example, in underground environments such as in a mine shaft.

[0004] It would be advantageous to provide compositions for binding aggregate that do not necessarily require agitation or mechanical mixing with the aggregate in order to form a solid structure. It would also be advantageous to provide compositions for binding aggregate that are safe to use in underground environments.

Summary of Invention

[0005] In a first aspect, the present invention provides a composition for binding aggregate.

The composition comprises reactive precursors which, when mixed, react to solidify.

Following mixing of the reactive precursors, the composition has a viscosity such that, when

poured onto aggregate that has been pre-arranged to define a road base, the composition

percolates through the aggregate whilst reacting, whereby a road incorporating the aggregate

is formed without mechanical mixing.

[0006] The composition of the present invention can advantageously be used to produce a

solid structure in the form of a road without the need for any mechanical mixing (e.g. by

agitating the aggregate or by applying the composition at high pressure). The composition of

the present invention can simply be poured over the pre-arranged aggregate, whereupon its

viscosity enables it to percolate through the heaped aggregate whilst reacting to solidify,

coating aggregate particles from the top to the bottom of the road base along the way, such

that substantially all of the aggregate becomes incorporated into the solid matrix.

Advantageously, because all that is required to produce the road is to pour the composition

over the pre-arranged aggregate, embodiments of the compositions of the present invention

may be used to produce hard road surfaces in locations where such might otherwise be

challenging, for example, in mine shafts.

[0007] In some embodiments, the composition of the present invention may be adapted for

use in an underground environment. The composition may, for example, further comprise an

antistatic agent. The composition may, for example, further comprise a fire retardant.

[0008] In a second aspect, the present invention provides a composition for use in an

underground environment. The composition comprises reactive precursors which, when

mixed, react to solidify, an antistatic agent and a fire retardant.

[0009] In some embodiments, the compositions of the second aspect of the present invention

may have a viscosity (i.e. after mixing of the reactive precursors) whereby it adheres to

aggregate upon application thereto, whereupon a structure incorporating the aggregate is

formed upon solidification. In some embodiments, the compositions of the second aspect of

the present invention may have a viscosity (i.e. after mixing of the reactive precursors)

whereby it adheres to aggregate upon application thereon, whereupon a structure

incorporating the aggregate is formed upon percolation of the composition through the aggregate and solidification (i.e. without necessarily requiring any mechanical mixing of the composition and aggregate, as is the case for the first aspect).

[0010] Solid structures which are formable using embodiments of the compositions of the

present invention include, for example, road bases and road surfaces.

[0011] In some embodiments, the reactive precursors may be components of a polymer

system (e.g. the reactive precursors may be monomers). Such a polymer system may, for

example, comprise reactive precursors which react to form a polyurethane (e.g. a polyol and

an isocyanate). Polyurethane polymers are typically highly durable and have elastomeric

properties, making them useful for a wide range of applications.

[0012] In some embodiments, the compositions of the present invention present invention

may comprise additional components, which impart further advantageous properties to the

composition. For example, in some embodiments the composition may further comprise a

process oil. For example, in some embodiments the composition may further comprise a

viscosity modifier (e.g. a rosin ester).

[0013] The compositions of the present invention may, for example, comprise castor oil, a

rosin ester, a process oil and an isocyanate (which would be held separately to the other

components during storage). Such a composition may, in some embodiments further

comprise an antistatic agent (e.g. Statsafe) and/or a fire retardant (e.g. Austhane).

[0014] In a third aspect, the present invention provides a composition for use in an

underground environment. The composition comprises:

between about 68-79% v/v castor oil;

between about 20-31% v/v of a rosin ester;

between about 0.67-1.04% v/v of a process oil;

about 0.0001% v/v Statsafe;

about 0.0002% v/v Austhane; and

an isocyanate, stored separately to the other components.

[0015] In a fourth aspect, the present invention provides a method for forming a road in an

underground environment. The method comprises:

arranging aggregate to define a road base;

providing a composition comprising reactive precursors which, when mixed, react to

solidify; causing the reactive precursors to mix and pouring the composition including mixed reactive precursors over the road base; and allowing the composition to percolate through the road base and react to solidify.

[0016] In some embodiments of the method of the present invention, the composition may be

the composition of the present invention, as described herein.

[0017] Additional features and advantages of the various aspects of the present invention will

be described below in the context of specific embodiments. It will be appreciated, however,

that such additional features may have a more general applicability in the present invention

than that described in the context of these specific embodiments.

Description of Embodiments

[0018] The present invention can advantageously provide compositions which can be used in

underground environments such as mines and/or which are pourable onto aggregate in order

to form solid structures such as roads without necessarily having to perform mechanical

mixing.

[0019] The present invention thus provides a composition for binding aggregate and which

may be adapted for use in an underground environment. The composition comprises reactive

precursors which, when mixed, react to solidify. Following mixing of the reactive

precursors, the composition has a viscosity such that, when poured onto aggregate that has

been pre-arranged to define a road base, the composition percolates through the aggregate

whilst reacting, whereby a road incorporating the aggregate is formed without mechanical

mixing.

[0020] The present invention also provides a composition for use in an underground

environment. The composition comprises reactive precursors which, when mixed, react to

solidify, as well as an antistatic agent and a fire retardant.

[0021] The compositions of the present invention find particular application for use in

underground environments, where extreme safety precautions must be taken because of the

confined space and where the physical environment presents challenges not experienced

above ground. The invention will be described in further detail below mainly in this context.

It will be appreciated, however, that the present invention need not be limited to underground

applications, and may also be useful in above ground applications.

[0022] As used herein, the phrase "mechanical mixing" is to be understood as being the action where aggregate particles are physically agitated in the presence of a composition in

order to thoroughly mix the two. For example, existing techniques for mechanically mixing

aggregates with other components include cement mixers, or rotary mixers.

[0023] The viscosity of the composition after mixing of the reactive precursors (i.e. at around

about the time it is poured and immediately afterwards) is important because it is this

characteristic pf the (mixed) composition which ensures that substantially all of the aggregate

becomes incorporated into the solid structure without necessarily having to perform

mechanical mixing. If the composition is too viscous at the time it is poured, it will tend to

not percolate to the bottom of the pre-arranged aggregate, and the lower aggregate might not

be incorporated into the solid structure. High viscosity compositions may also be difficult or

energy intensive to pump. Similarly, if the composition is not viscous enough at the time it is

poured, it will tend to flow straight through the aggregate without being retained on the

aggregate, where it pools at the bottom of the pre-arranged aggregate with upper aggregate

not being incorporated into the solid structure.

[0024] As would be appreciated, the viscosity of the composition will increase with time and

as the reactive precursors react to solidify. The rate of reaction is therefore also a

characteristic of the invention, with any rate of reaction that produces the defined result being

within the scope of the present invention. It is within the scope of a person skilled in the art,

using the teachings contained herein and routine trial and experimentation, to determine if a

particular composition has an appropriate viscosity and reaction rate.

[0025] The viscosity of the composition may be imparted by the reactive precursors,

although other components of the composition may also contribute to its resultant viscosity.

Such other components will be described in further detail below.

[0026] The compositions of the present invention include reactive precursors which, when

contacted with each other, react to solidify. The reactive precursors would therefore be

maintained separately from each other in the composition before it is ready for use, in order

to prevent premature reaction and solidification. The reactive precursors may, for example,

be held in separate containers before mixing.

[0027] The reactive precursors may be mixed at any stage before, during or even

immediately after application (e.g. by pouring) onto the aggregate. Typically, the reactive

precursors would be mixed immediately before application to the aggregate, in order to ensure a thorough mixing has occurred, but before significant reactions have occurred, which might increase its viscosity. Typically, the reactive precursors are provided in liquid forms, with the liquid streams being mixed pre-pouring. In specific embodiments, apparatus like those described in the applicant's co-pending patent application (Australian patent application no. 2018250520, the contents of which are hereby incorporated by reference) may be used to separately store, mix and then apply the reactive precursors.

[0028] Any common aggregates currently used in construction industries may be used in the

present invention. Typically, aggregates having a mixture of particle sizes would be used, in

order to produce a more intimately mixed solid product. The aggregate may be obtained

from any suitable source, and may be a waste material (e.g. mining tailings could be

repurposed and used as a road base and therefore not need to be removed from the mine).

[0029] The compositions of the present invention include reactive precursors which, when

mixed, react to solidify. Bearing in mind its purpose, any reactive precursors which, when

mixed, react to form a solid matrix may be used in the present invention. Typically, the

reactive precursors are components of a polymer system (i.e. precursors which, when they are

caused to react together, form a polymer), polymers being effective at binding particles

together and forming a structure having advantageous properties such as durability, resilience

and longevity. Roads formed from polymer systems, such as those described below, have

also been found to have a degree of pliability, making them less bumpy to drive over and

hence more comfortable for drivers.

[0030] In some forms, for example, the polymer system may have reactive precursors which

react to form a polyurethane. The polymer system may therefore include a polyol and an

isocyanate (or one or more polyol(s)/isocyanate(s)). That is, the reactive precursors are

polyol and isocyanate monomers.

[0031] The reactive precursors may, for example, be a di- or tri-poly-isocyanate and a polyol.

The polyol may, in some embodiments, be derived from a biological source, e.g. castor oil,

but any poly hydroxyl-containing chemical species compatible with the composition

described herein might also be used. The isocyanate may, in some embodiments, be a

diisocyanato-diphenylmethane (MDI)-based composition (e.g. PM200, sold by Hilditch Pty Ltd).

[0032] In some embodiments, the ratio of polyol : isocyanate in the composition may be

between about 4:1 and about 2:1. In some embodiments, the ratio of polyol and isocyanate is between about 3.5:1 and 1:1. In general, and provided that the required functionality is achieved, using less isocyanate is preferable. Isocyanate is a relatively toxic chemical, the use of which should ideally be minimised. Furthermore, including too much isocyanate in the composition may cause too rapid a reaction rate, resulting in non-homogeneous and potentially brittle structures being formed. As described above, the polyol and isocyanate components of the composition would be separately maintained until ready for pouring, in order to prevent pre-setting of the polymer.

[0033] The compositions of the present invention may include other components, such as a

process oil and/or viscosity modifier.

[0034] As noted above, the viscosity of the composition may be affected by components

other than the reactive precursors. In some embodiments, for example, the composition may

comprise a high molecular weight polymer that is miscible with the other components of the

composition. In some embodiments, for example, a rosin ester may be included in the

composition. Rosin esters can be used to adjust the average molecular weight of the

polymers in the composition and hence its viscosity. Rosin esters can also increase the

tackiness of the composition, which may assist with its adherence to the surfaces of the

aggregate particles. A specific rosin ester trialled by the inventors is a glycerol ester of

hydrogenated rosin (CAS no. 65997-13-9).

[0035] In other embodiments, the rosin ester may be partially or completely replaced with

another resin (which is miscible with the other components of the composition), such as

ethylene vinyl acetate (EVA), the presence of which results in the formation of an elastic

polymer having a relatively high toughness.

[0036] The viscosity modifier (e.g. rosin ester) may be provided with either of the separately

stored reactive precursors, provided that it will not react with the precursor during storage. In

compositions including a polyol and an isocyanate, for example, a rosin ester would usually

be dissolved into the polyol component of the composition. The viscosity modifier might

even, in some embodiments, be provided separately from both of the reactive precursors,

although any benefits of doing so may not be practically worthwhile.

[0037] In some embodiments, the composition may further comprise a process oil. A process

oil may, for example, help to solubilise the components of the composition or may adjust the

compositions viscosity is a beneficial manner. Suitable process oils include, for example,

Shell Catenex Oil S 321 (CAS no. 64742-65-0).

[0038] The process oil may also be provided with either of the separately-stored reactive

precursors, provided that it will not react with the precursor during storage. In compositions

including a polyol and an isocyanate, for example, a process oil would usually be dissolved

into the polyol component of the composition.

[0039] In some embodiments, the composition may also include an antistatic agent in order

to reduce or prevent the risk of a static discharge occurring during handling of the

composition. As will be appreciated, such a functionality would be considered essential in

many applications, and especially in mining applications. The antistatic agent may, for

example, be the commercially-available product Statsafe. The liquid composition may, for

example, comprise about 0.0001% v/v Statsafe.

[0040] In some embodiments, the liquid composition may further comprise a fire retardant in

order to reduce or prevent the risk of fire, for similar reasons to those discussed above. The

fire retardant may, for example, be Austhane. The liquid composition may, for example,

comprise about 0.0002% v/v Austhane.

[0041] Compositions that include an antistatic agent and a fire retardant may be especially

useful in underground applications, where the risk of a spark or introduction of a flammable

material might have dangerous consequences.

[0042] Similar to that described above, the antistatic agent and/or fire retardant may be

provided with either of the separately-stored reactive precursors, provided that it will not

react with the precursor during storage. In compositions including a polyol and an

isocyanate, for example, these components would typically both be dissolved into the polyol

component of the composition.

[0043] In specific embodiments of the invention, the composition may comprise:

castor oil;

a rosin ester;

a process oil; and

an isocyanate, held separately to the other components (e.g. in a separate container).

[0044] More specific embodiments of this composition, which have been trialled by the

inventors and which are described below, may comprise:

between about 68-79% v/v (e.g. about 79%) castor oil;

between about 20-31% v/v (e.g. about 20%) of a rosin ester;

between about 0.67-1.04% v/v (e.g. about 1%) of a process oil; if present, about 0.0001% v/v Statsafe; and if present, about 0.0002% v/v Austhane.

[0045] It is within the ability of a person skilled in the art in light of the teachings contained

herein to adapt the compositions described above when using other forms of reactive

precursors and/or components. In light of the disclosure contained herein, routine trial and

experimentation can be utilised in order to formulate a composition which will fall within the

scope of the present invention, as defined either by its composition or by its viscosity and

solidification properties when poured over aggregate.

[0046] The present invention also provides a method for forming a road in an underground

environment. The method comprises:

arranging aggregate to define a road base;

providing a composition comprising reactive precursors which, when mixed, react to

solidify; causing the reactive precursors to mix and pouring the composition including mixed

reactive precursors over the road base; and

allowing the composition to percolate through the road base and react to solidify.

[0047] In some embodiments of the method of the present invention, the composition may be

the composition of the present invention, as described herein.

[0048] The volume of the composition applied will vary depending on a number of factors,

the most important of which will be the volume of the solid structure to be formed (e.g. the

depth of the aggregate formed into a road base). Other factors which might influence the

volume of the mixed composition applied to a given area of the formed aggregate may

include the humidity, wetness of the aggregate, etc. It is envisaged that between about 0.5

and about 10L per square metre would be used in the method of the present invention, with

between about 3-5L per square metre being sufficient for many applications.

[0049] Using only routine techniques, the compositions of the present invention may also be

used for applications other than forming a road in an underground environment.

[0050] Specific embodiments of the present invention trialled by the inventors will now be

described. In a specific form, the present invention provides a composition having the

following components:

Composition A

Castor oil 79.26%

Rosin Ester 20.06%

Process oil 0.67%

Statsafe 0.0001%

Austhane 0.0002%

[0051] The Castor oil may, for example, be commercially obtained as Ricinus Communis (Castor) Seed Oil (1st pressing, CAS no. 8001-79-4). The Rosin ester may, for example, be commercially obtained as the glycerol ester of hydrogenated rosin (CAS no. 65997-13-9). The process oil may, for example, be commercially obtained as Shell Catenex Oil S 321 (CAS no. 64742-65-0). Composition A was formed in a 3000L vat, with a slowly moving mixing blade inside. Roughly 70% v/v castor oil, 29% rosin ester and 1% of a base oil were used to form the composition although it is not possible to rapidly add the rosin to the mixture or it forms a gluggy mess and will take a long time to dissolve. The rosin ester is therefore fed into the castor oil slowly in the following manner. The castor oil is firstly heated to 105°C and, once it is at about 90°C, the rosin ester (which comes in a chip form) is slowly added (over a day and a half) so that it dissolves and the composition becomes a thick syrup. Once the rosin ester has all been dissolved into the castor oil, the base oil is added with mixing. Finally, once the composition has cooled down, it is transferred to an ICB (1000L plastic cube with a steel frame around it) for storage. The inventors have found that this "Part A" composition of Castor oil, Rosin Ester and Process oil stays fluid and does not harden.

[0052] The castor oil in Composition A is one of the reactive precursors, the other reactive precursor being an isocyanate that is stored separately from the other components of the composition. In the trials described below, the "Part B" isocyanate used was PM200, one of the most stable and least volatile isocyanates.

[0053] Using the method described below, Composition A was used to form a road in a mine shaft.

• The mine's over burden (e.g. rock coal, roof material, slop, washed coal and rock) was spread over the floor of the mine shaft, and was then flattened and levelled using a bucket or grader to define a road base. • Composition A was then pumped from its storage container, mixed in-line with the isocyanate (using the apparatus described in Australian patent application no. 2018250520), and then poured over the road base evenly at a volume of 3 to 4L per square meter. • The composition was then left to percolate down through the heaped aggregate whilst, at the same time, reacting to form a solid polyurethane matrix around the aggregate. In dry areas, it takes 4 to 5 hours to set well enough for heavy machines to drive on, and was fully set after 10 hours.

[0054] Composition A was used to form another road in a mine shaft, using the method described below.

• aggregates intended for roadways (e.g. slabs, longwall installs and take offs, sumps, drive-head foundations, ch4 stubbs etc.) were transported into the mine and spread out evenly using a bucket or grader. Depending on the aggregate material, it may be necessary to use formwork in order to contain the aggregate. • Once the aggregate is level, Composition A was pumped from its storage container, mixed in-line with the isocyanate, and then poured over the road base evenly at a volume of 3 to 4L per a square meter, as required for depth. • The depth of the penetration of the Composition A/isocyanate mixture is determined based on the sizes of the aggregate. For example, for aggregate particles having an average diameter of about 5mm, the mixed composition would usually penetrate to a depth of between 30 to 40mm. For aggregate particles having an average diameter of about 10mm, the mixed composition would usually penetrate to a depth of between 40 to 80ml. For aggregate particles having an average diameter of about 20mm, the mixed composition would usually penetrate to a depth of between 80 to 200mm.

[0055] Other specific compositions of the present invention trialled by the inventors in methods such as those described above include the following:

Composition B

Castor oil 67.86%

Rosin Ester 31.10%

Process oil 1.04%

Statsafe 0.0001%

Austhane 0.0002%

Composition C

Castor oil 75.28%

Rosin Ester 23.92%

Process oil 0.80%

Statsafe 0.0001%

Austhane 0.0002%

Composition D

Castor oil 76.19%

Rosin Ester 22.04%

Process oil 077%

Statsafe 0.0001%

Austhane 0.0002%

Composition E

Castor oil 77.04%

Rosin Ester 22.21%

Process oil 0.74%

Statsafe 0.0001%

Austhane 0.0002%

Composition F

Castor oil 77.83%

Rosin Ester 21.45%

Process oil 0.72%

Statsafe 0.0001%

Austhane 0.0002%

Composition G

Castor oil 78.57%

Rosin Ester 20.73%

Process oil 0.69%

Statsafe 0.0001%

Austhane 0.0002%

[0056] The inventors found that Compositions B to G functioned in a similar manner to

Composition A, in that they formed a strong matrix around the aggregate. However, the

viscosity of some compositions was slightly higher than that of Composition A, making the

mixed composition (i.e. after addition of the Part B isocyanate) more difficult to pump and less able to percolate through the full depth of stacked aggregate, especially at lower temperatures.

[0057] In another trial, compositions in accordance with the present invention were used to

form a road in a mine shaft, using wet/sloppy coal or other wet/sloppy materials to form the

road base. The formed wet aggregate road base needed to be covered using 4 to 5L of the

mixed composition per square meter.

[0058] In such embodiments, the inventors found that it may be beneficial to use a different

applicator (e.g. a nozzle) in order to penetrate through the wet/sloppy material. Simply

pouring the mixed composition onto the wet aggregate did not always ensure adequate

mixing and the subsequent formation of a homogeneous road. In such embodiments, the

inventors found it necessary to use shovels, vibrators and/or stirrers to mix the binder

composition with the wet/sloppy aggregate materials. However, due to the composition's unique composition, it was safe to use in the mine. The inventors note that these

embodiments may take longer to set and may swell up slightly (due to foaming reactions

occurring with the water).

[0059] In yet another trial, compositions in accordance with the present invention were

injected into roadway cracks to stop water making trouble areas. The formed wet aggregate

road base needed to be covered using 4 to 5L per square meter. In this trial:

• Holes having different diameters (e.g. 15 to 35mm holes) were drilled into the

cracked roadways where water-make problems arise. The holes were drilled to a

depth of 1 to 2mtrs using a different applicator nozzle (the nozzle is determined by the

width of the hole drilled). • A nozzle was pushed into drilled hole and the mixed composition pumped into the

hole until it was visually noticed at the surface of the hole. The nozzle was then

removed, and the process repeated until all of the drilled holes are filled with the

composition.

[0060] This process should fill in all the cracks of roadway by expanding when the

composition meets the water in the roadway, and should therefore bind and block water

emerging to the surface of the roadway and stop further deterioration of the roadway. As

would be appreciated, this would allow control over where water goes throughout the mine.

[0061] In summary, the invention relates to compositions for binding aggregate, and

especially in underground environments. It will be appreciated form the disclosure set out above that the present invention provides a number of new and useful results. For example, specific embodiments of the present invention may provide one or more of the following advantages:

• the present invention can greatly simplify the process for forming solid road

surfaces in mine shafts, requiring fewer personnel and less equipment;

• the present invention can be used to form solid road surfaces in mine shafts

without having to pressurise or aspirate any components, making it safer and less

subject to regulation;

• the composition is safe for use in underground environments such as mines; and

• solid structures of bound aggregate can be formed without the need for

mechanical mixing and agitation typically required by current processes.

[0062] It will be understood to persons skilled in the art of the invention that many

modifications may be made without departing from the spirit and scope of the invention. All

such modifications are intended to fall within the scope of the following claims.

[0063] In the claims which follow and in the preceding description of the invention, except

where the context requires otherwise due to express language or necessary implication, the

word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or

addition of further features in various embodiments of the invention.

Claims (1)

CLAIMS:

1. A composition for binding aggregate, the composition comprising

reactive precursors which, when mixed, react to solidify,

whereby, following mixing of the reactive precursors, the composition has a viscosity

such that, when poured onto aggregate that has been pre-arranged to define a road

base, the composition percolates through the aggregate whilst reacting, whereby a

road incorporating the aggregate is formed without mechanical mixing.

2. The composition of claim 1, wherein the composition is adapted for use in an

underground environment.

3. The composition of claim 2, wherein the composition further comprises an antistatic

agent.

4. The composition of claim 2 or claim 3, wherein the composition further comprises a fire

retardant.

5. A composition for use in an underground environment, the composition comprising

reactive precursors which, when mixed, react to solidify;

an antistatic agent; and

a fire retardant.

6. The composition of claim 5 wherein, following mixing of the reactive precursors, the

composition has a viscosity such that it adheres to aggregate upon application thereto,

whereupon a structure incorporating the aggregate is formed upon solidification.

7. The composition of any one of claims 3, 5 and 6, wherein the antistatic agent is Statsafe.

8. The composition of any one of claims 4 to 6, wherein the fire retardant is Austhane.

9. The composition of any one of claims 1 to 8, wherein the reactive precursors are

components of a polymer system.

10. The composition of claim 9, wherein the polymer system comprises reactive precursors

which react to form a polyurethane.

11. The composition of claim 9 or claim 10, wherein the polymer system comprises a polyol

and an isocyanate.

12. The composition of claim 11, wherein the polyol is derived from a biological source.

13. The composition of claim 11 or claim 12, wherein the polyol is a castor oil.

14. The composition of any one of claims 11 to 13, wherein the isocyanate is a diisocyanato

diphenylmethane(MDI)-based composition.

15. The composition of any one of claims 11 to 14, wherein a ratio of polyol and isocyanate

in the polymer system is between about 3.5:1 and 1:1.

16. The composition of any one of claims 1 to 15, wherein the reactive precursors are stored

in separate containers before mixing.

17. The composition of any one of claims 1 to 16, wherein the composition further comprises

a process oil.

18. The composition of any one of claims 1 to 17, wherein the composition further comprises

a viscosity modifier.

19. The composition of claim 18, wherein the viscosity modifier is a rosin ester.

20. The composition of any one of claims 1 to 19 comprising:

castor oil;

a rosin ester;

a process oil; and

an isocyanate, stored separately to the other components.

21. The composition of claim 20 comprising:

about 79% v/v castor oil;

about 20% v/v of a rosin ester; and

about 1% v/v of a process oil.

22. The composition of claim 20 or claim 21, further comprising:

about 0.0001% v/v Statsafe; and

about 0.0002% v/v Austhane.

23. A composition for use in an underground environment, the composition comprising

between about 68-79% v/v castor oil;

between about 20-31% v/v of a rosin ester;

between about 0.67-1.04% v/v of a process oil;

about 0.0001% v/v Statsafe; about 0.0002% v/v Austhane; and an isocyanate, stored separately to the other components.

24. The composition of claim 23, wherein the ratio of castor oil and isocyanate is between

about 3.5:1 and 1:1.

25. A method for forming a road in an underground environment, the method comprising:

arranging aggregate to define a road base;

providing a composition comprising reactive precursors which, when mixed, react to

solidify; causing the reactive precursors to mix and pouring the composition including mixed

reactive precursors over the road base; and

allowing the composition to percolate through the road base and react to solidify.

26. The method of clam 25, wherein the composition is the composition of any one of claims

1 to 24.