Patent Description:
The present disclosure relates to the fabrication of elongate concrete articles such as poles, piles or pipes. In a particular form, the present disclosure relates to process improvements for facilitating the mass production of these concrete articles.

The present Applicant has developed a vertical casting system for fabricating elongate concrete articles such as poles and the like that includes the steps of introducing a concrete mix having a relatively high water to cement ratio into a fabrication assembly consisting of a core assembly and an outer mould. The concrete mix is then dewatered in a first stage as it is pumped generally upwardly against gravity into the mould cavity that formed between the core assembly and the fabrication assembly by controlling the release of water resulting from the combined head pressure and pump pressure of the concrete mix as the concrete mix is pumped into the mould cavity. The concrete mix is then further dewatered in a second stage following filling of the mould assembly.

Once the concrete reaches a compressive strength of approximately <NUM>-<NUM> MPa it is possible to remove the concrete product from the mould and place it in a curing chamber. Aspects of this vertical casting system are described in International Patent Application No. <CIT> (<CIT>) titled "METHOD AND SYSTEM FOR FABRICATION OF ELONGATE CONCRETE ARTICLES".

While the vertical casting process has addressed a number of issues relating to initial casting of the concrete article, there is still some variability in the time between the mould assembly being filled and the concrete developing suitable strength for the subsequent stripping or removal of the mould assembly to allow the concrete article to be then cured. This is due primarily to temperature effects including ambient temperature and the temperature of components of the casting system, including the concrete mix, which affect the hydration speed of the concrete mix and as a result its strength. Removal of the mould assembly where the concrete has not reached a suitable surface strength can lead to surface defects as the inner mould surface of the outer mould will not release from the concrete article.

In an attempt to address this issue, latex based flexible materials have been employed as a liner between the inner mould surface of the outer mould and the concrete mix to assist in the release of the mould from the concrete article following casting. The latex liner is designed and fabricated to have an initial circumference that is smaller than the mould that supports the liner. When concrete is pumped into the mould, the latex liner will expand due to the pressure of the concrete until it eventually comes into contact with the inner mould surface of the outer mould which then limits any further expansion during casting.

Upon opening of the mould, ie, by separating the mould halves, the latex liner is intended to return to its original or relaxed configuration in the process sliding over the fresh concrete surface of the moulded article in the process breaking the surface tension between the latex liner and the fresh concrete to, in theory, allow removal of the newly cast concrete article from the mould liner. In addition to reducing surface defects, the latex liner would reduce the need to continually clean the moulding surfaces of the outer mould.

However, it has been found that these latex liners can be damaged easily in a manner that cannot be easily repaired. In addition, the flexible liner tends to sag and deform within the mould assembly which can also affect the surface finish of the resultant concrete article due to creases and folds in the liner material.

While the use of a latex liner has provided some improvement to the release characteristics of the mould assembly, operator misjudgement as to timing of when the concrete article may be stripped from the mould can still result in the surface of the concrete remaining on the mould liner during removal of the outer mould and a mould liner which is unsightly. Additionally, concrete will build up on the liner surface resulting in the liner requiring scrubbing in a solution of a hydrochloric acid which is not only time consuming but also a potentially hazardous activity. As would be appreciated, damage to the mould liner will cause a halt in production until the mould liner is fixed.

There is therefore a need for a fabrication method for forming elongate concrete articles capable of addressing or at least ameliorating one or more of the above disadvantages or to provide a useful commercial alternative.

<CIT> is titled "SIMULATED TREE FURNITURE AND METHOD OF MOLDING SAME" and is directed to fabricating novelty shaped furniture from concrete and in particular to the use of a flexible plastic mold in the fabrication of a tree trunk shaped furniture base where the mold has the profile of a tree trunk. Following casting of the tree trunk shaped base, the flexible plastic mold is peeled from the cast article leaving the appearance of a tree trunk.

<CIT> is titled "METHOD FOR RAPID MOLDING OF ELONGATE CONCRETE ARTICLE" and is directed to a molding arrangement involving an inner mold construction and an outer mold construction that define a mold cavity into which wet or uncured concrete is introduced. The concrete is compressed in molding of the concrete article by movement of the inner mold relatively toward the outer mold to remove surplus liquid from the inner surface of the concrete so that the concrete is at least partially cured. Additionally, the compression applied on the inner surface of the concrete by the inner mold is maintained while inward pressure is applied over the outer surface of the concrete by the outer mold to remove surplus surface liquid from the outer surface of the concrete.

In a first aspect, the present disclosure provides a fabrication assembly for fabricating an elongate concrete article in a substantially upright configuration, including:.

In another form, the mould liner is formed as a sleeve having the shape and configuration of the elongate concrete article being cast.

In another form, the mould liner is removable from the elongate concrete article as a unitary item following casting.

In another form, the mould liner is removed from the elongate concrete article by peeling the mould liner from the elongate concrete article.

In another form, the mould liner is formed from a woven fabric material.

In another form, the woven fabric material has a tensile strength (warp/weft) of greater than <NUM>/<NUM> N/<NUM>.

In another form, the woven fabric material is formed from a synthetic plastic material.

In another form, the mould liner includes a hydrophobic coating.

In another form, the hydrophobic coating is a synthetic hydrophobic plastic material.

In another form, the mould liner is formed from a single sheet of material.

In a second aspect, the present disclosure provides a method for fabricating an elongate concrete article, including:.

In another form, the mould liner is removed from the elongate concrete article as a unitary item.

In another form, removing the mould liner includes peeling the mould liner from the elongate concrete article.

In another form, casting the concrete article includes.

Embodiments of the present disclosure will be discussed with reference to the accompanying drawings wherein:.

In the following description, like reference characters designate like or corresponding parts throughout the figures.

Referring now to <FIG>, there is shown a flow chart diagram of a method <NUM> for fabricating an elongate concrete article according to an illustrative embodiment. In this illustrative embodiment, the present disclosure is discussed in relation to a <NUM> metre hollow section <NUM>/<NUM> kN slack cage tapered cylindrical concrete pole having a general wall thickness of <NUM> and suitable for the distribution of power. As would be appreciated by those skilled in the art, the present disclosure will be equally applicable to other hollow concrete articles including, but not limited to piles, poles or pipes either of constant cross section or varying cross sectional size and profile.

At step <NUM>, the concrete article is cast in a fabrication assembly. Referring now to <FIG> and <FIG>, there are shown exploded and assembled views respectively of a fabrication assembly <NUM> consisting of, in this illustrative embodiment, a core assembly <NUM>, two opposed tapered semi cylindrical mould portions <NUM> forming an outer mould assembly <NUM> and optional reinforcement cage <NUM> that seats within the tapered annular shaped cavity or moulding region <NUM> formed between the core assembly <NUM> and the joined outer mould portions <NUM>.

Fabrication assembly <NUM> further includes a mould liner <NUM> which is configured to form an intermediate layer between the inner moulding surface <NUM> of the outer mould assembly <NUM> and the elongate concrete article being cast. In this illustrative embodiment, mould liner <NUM> is configured as a tapered open-ended sock or sleeve having the shape and configuration of the article being cast and will function to from a containment layer for the elongate concrete article to form a mould liner and contained elongate concrete article combination. In one example, mould liner <NUM> is configured to allow transport of the mould liner <NUM> and the contained or included concrete article combination following casting for removal from the fabrication assembly. Mould liner <NUM> is held upright in fabrication assembly <NUM> by two opposed longitudinal straps <NUM> extending from the top of the mould liner <NUM>.

In another embodiment, a top region or flap portions of the mould liner <NUM> are folded over the top edge of the outer mould assembly <NUM> to retain the mould liner <NUM> in place during the casting process. This arrangement is typically employed where the mould liner <NUM> and the moulded concrete article <NUM> is the same or similar length as outer mould assembly <NUM>. In other embodiments, the mould liner <NUM> is of a reduced length as compared to the outer mould assembly <NUM> and in this case longitudinal straps <NUM> of appropriate length may be used to retain mould liner <NUM> in the outer mould assembly <NUM> at the correct height.

In one illustrative example, the outer mould assembly <NUM> is <NUM> metres long which is designed to cast concrete articles of an equivalent length, however, in accordance with the present disclosure a concrete article of reduced length, say <NUM> metres, could be cast using the same outer mould assembly <NUM> but by using a reduced length mould liner <NUM> of equivalent length which is positioned and located within the outer mould assembly <NUM> using longitudinal straps <NUM> that extend from the mould liner as discussed above.

In an illustrative embodiment, the mould liner <NUM> is formed from a woven fabric material having a tensile strength (warp/weft) of greater than <NUM>/<NUM> N/<NUM> where the warp extends longitudinally with respect to the mould liner and the weft extends circumferentially with respect to the mould liner. In other embodiments, the tensile strength (warp/weft) of the woven fabric material is greater than, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM>, <NUM>/<NUM> N/<NUM> or <NUM>/<NUM> N/<NUM>. In another embodiment, the mould liner <NUM> is configured with the warp of the woven fabric material extending circumferentially with respect to the mould liner and the weft extending longitudinally with respect to the mould liner.

In another embodiment, the woven fabric is formed from a synthetic plastic material selected from the group consisting of polypropylene, polyethylene, linear low density polyethylene, polyamides, high density polyethylene, polyesters, polystyrene, polyvinyl chloride and their associated copolymers and further including any mixtures of these materials. In yet another embodiment, the woven material is coated by a hydrophobic or water resistant coating. In one example, the hydrophobic material is a synthetic hydrophobic plastic material such as polyvinyl chloride (PVC) but as would be appreciated other suitable hydrophobic materials may be employed.

In one example, the woven fabric material is a polyester weave incorporating a PVC coating that is <NUM> grams per square metre (gsm) in weight and having a thickness of approximately <NUM>. In one example, mould liner <NUM> is formed from Polymar™ <NUM> material which is typically used in applications such as the fabrication of truck tarpaulins.

A table of the properties of the Polymar™ <NUM> material is set out below:.

In this embodiment, mould liner <NUM> is fabricated from a sheet of material that is cut out to have an outline corresponding to any required taper and whose edges are joined together using standard plastic ultra-high frequency welding or other plastic welding techniques such as hot plate welding using a platen. In this way, the mould liner <NUM> may be fabricated to high dimensional tolerances on the diameter of approximately ± <NUM>.

Concrete mix is introduced in cavity <NUM> by concrete mix input assembly <NUM> consisting of elbow portion <NUM> having an inlet <NUM> to receive the concrete mix and whose outlet <NUM> is joined to the bottom of joined mould portions <NUM>. Concrete input assembly <NUM> further includes drain outlet <NUM> to allow water to drain from core assembly <NUM>.

Core assembly <NUM> includes a tapered hollow core portion <NUM>. In this example embodiment, surrounding the core portion <NUM> is an inflatable bladder <NUM> that functions to expand or extend radially outwards from the core portion <NUM>. Attached to the bladder <NUM> is a plurality of elongate longitudinally extending mesh drainage strips <NUM> spaced around bladder <NUM> and extending along core portion <NUM> forming respective drainage channels that terminate in a collection tube <NUM>, which together in this embodiment forms drainage means for draining water from the concrete mix during the fabrication process.

Each drainage strip <NUM> is formed from a plastic mesh material having a cell dimension of approximately <NUM> x <NUM> and having a width of approximately <NUM> which allows water to drain along the drainage strip. In this illustrative embodiment, the plastic mesh is formed from high-density polyethylene (HDPE) but as would be appreciated other types of suitable materials may be employed. In this illustrative embodiment, four drainage strips <NUM> are employed but this number may be varied depending on the size and configuration of the pole and expected drainage rates. Surrounding the bladder <NUM> and drainage strip <NUM> arrangement is a filter membrane <NUM> which again extends substantially along the length of core portion <NUM>. On assembly, collection tube <NUM> is inserted through drain outlet <NUM> to receive water from drainage strips <NUM>.

In this illustrative embodiment, directed to fabricating a <NUM> metre power pole, filter membrane <NUM> is a woven polyester fabric having a mesh or pore size of <NUM> but this may be varied depending on the concrete mix and type of pole being fabricated. Filter membrane <NUM> is held in place by a suspender arrangement (not shown) that attaches to the top of core portion <NUM> consisting of longitudinal strapping that is used to transfer the load when the bladder <NUM> and filter membrane <NUM> are removed from the moulded product. Filter membrane <NUM> in this illustrative embodiment functions as both a pressure drop means to provide a pressure drop that in part controls the transfer of water across the membrane during dewatering as well as providing a filtering means to prevent loss of fines and cement during the filling process.

Concrete mix is then pumped into the fabrication assembly <NUM> with a first stage dewatering of the concrete mix occurring by a controlled release from the combined head pressure as a result of the concrete mix being pumped generally upwardly against gravity and the pump pressure as concrete mix is introduced into cavity <NUM>. As a result, a pressure drop is induced across the filter membrane <NUM> resulting in liquid transferring through the filter membrane <NUM> to be collected by the drainage means in the form of drainage strips <NUM> located between the core portion <NUM> and filter membrane <NUM>.

The pressure drop across filter membrane <NUM> is a function of the head pressure, water to cement ratio, cement mix design, pumping pressure and related pump time. For a given configuration, the primary control variable is the pumping pressure of the concrete mix which also determines how quickly the concrete mix will rise in the mould cavity <NUM>. The pumping pressure is controlled so as to allow liquid to escape from the concrete mix through filter membrane <NUM> to be drained by drainage strips <NUM> but not so fast that the drainage means is overwhelmed taking into account that the pressure drop will vary with the height of the fabrication assembly <NUM>.

The concrete mix then goes through a second stage dewatering after fabrication assembly <NUM> has been substantially filled with the concrete mix by the action of a radial compressing means in the form of bladder <NUM> located between the core portion <NUM> of fabrication assembly <NUM> and filter membrane <NUM> which is inflated to a pressure of <NUM> psi and functions to compress the concrete mix between the bladder <NUM> of the fabrication assembly <NUM> and the mould liner <NUM> which lies against outer mould portions <NUM> of the fabrication assembly <NUM>. This compression force causes the remaining free water in the concrete mix to migrate through the mix and through filter membrane <NUM> where it is collected by drainage strips <NUM>.

As discussed previously, in the absence of a mould liner <NUM>, the time taken before the concrete is strong enough for the outer mould assembly <NUM> to be stripped is dependent on a number of factors including the ambient temperature, concrete temperature and mould temperature, where these factors all affect the hydration speed of the concrete, as well as the materials used in the concrete. As would be appreciated, these operating parameters can be difficult to control exactly and operator judgement is therefore required to determine when the cast concrete article is ready for stripping of the mould assembly. If the mould assembly is stripped too early this will impact on the ability of the mould surface to release from the surface of the concrete article and impact the surface finish of the concrete article.

At step <NUM>, the outer mould assembly <NUM> and core assembly <NUM> is stripped from the mould liner <NUM> and contained concrete article <NUM> combination. As can be seen in <FIG>, stripping of the mould assembly <NUM> first involves raising core assembly <NUM> from fabrication assembly <NUM> before the opening of mould portions <NUM>. In accordance with this illustrative embodiment, the mould liner <NUM> forms an outer containment layer or sleeve that encompasses concrete pole <NUM> and which in this example allows the mould liner <NUM> and the contained concrete pole <NUM> combination to be removed or transported together from the fabrication assembly <NUM> in an upright configuration following stripping of the outer mould assembly <NUM>. In another embodiment, the mould liner <NUM> and the contained concrete pole <NUM> remain held in an upright configuration and the fabrication assembly <NUM> is removed.

The pole is supported by two reinforcing bars in line with the mould liner straps <NUM> and the mould liner <NUM> and concrete pole <NUM> are together transferred for further curing.

As would be appreciated, as the outer mould assembly <NUM> is in contact with mould liner <NUM> during the stripping process, the removal of the outer mould assembly <NUM> will not be as dependent on the exact strength of the concrete pole <NUM> as the outer mould assembly <NUM> will release consistently from the mould liner <NUM>. As a result, the stripping process can proceed even though the concrete pole <NUM> contained within the mould liner <NUM> would not have attained the required compressive strength in order to be ready for stripping using a standard liner arrangement. In one example, the mould liner <NUM> is stripped from the concrete pole <NUM> once the concrete has reached a compressive strength of <NUM> kPa. In other embodiments, the mould liner <NUM> is stripped once the compressive strength of the concrete has reached one of the following values including <NUM> kPa, <NUM> kPa, <NUM> kPa, <NUM> kPa, <NUM> kPa, <NUM> kPa, <NUM> kPa, <NUM> kPa, <NUM> kPa or <NUM> MPa.

In this illustrative embodiment, directed to the fabrication of a <NUM> metre hollow section tapered cylindrical concrete pole having a general wall thickness of <NUM>, the time required to fill the mould with concrete is approximately <NUM>-<NUM> minutes followed by <NUM> minutes to then dewater the concrete as discussed above, meaning that the outer mould assembly <NUM> may be stripped approximately <NUM>-<NUM> minutes following filling of the mould and furthermore that this timing is consistent.

In process terms, use of the mould liner <NUM> increases the robustness of the casting process as the stripping step is decoupled from the exact state of the concrete pole <NUM> and as a consequence operator judgement and assessment of the hardness of the concrete pole <NUM> is not critical with the fabrication process as a result becoming less operator dependent.

At step <NUM>, the mould liner <NUM> is removed from the concrete pole <NUM>. In one example embodiment, the mould liner <NUM> is removed from concrete pole <NUM> approximately <NUM>-<NUM> hours following the removal of the mould liner <NUM> and contained concrete pole <NUM> combination from the fabrication assembly <NUM> and prior to lowering the concrete article from a vertical to a horizontal orientation. This exact time will depend on the rate of curing and ambient temperature of the environment following stripping of the mould assembly <NUM>. Referring now to <FIG>, the mould liner <NUM> is removed from the concrete pole <NUM> as a unitary item by peeling the mould liner <NUM> from the base of the taper. In this manner, the mould liner <NUM> may be removed as a unitary item without requiring any cutting of the liner material.

Once the mould liner <NUM> has been removed it may be then cleaned and reused. In this manner, the mould liner <NUM> may be removed without requiring a release agent or further cleaning due to its flexibility where flaky concrete residue will break away in the peeling process. In another embodiment, where reuse of mould liner <NUM> is not required, mould liner <NUM> is removed by cutting the mould liner material.

The Applicant has found that even though the mould liner is formed from a flexible woven material that would not be expected to have the same moulding properties as moulding assembly <NUM>, surprisingly the tensile strength of the mould liner is able to hold the concrete in compression following stripping of the mould assembly <NUM>. As a result, this allows the concrete article, which in this example embodiment weighs some <NUM>, to begin curing. The presence of the mould liner <NUM> also reduces premature drying out of the concrete during the curing process resulting in a stronger cast concrete article that has a better surface finish for comparable curing periods.

In the above described embodiment, the concrete pole has attained a sufficient hardness so that it can be lowered from a vertical orientation to a horizontal orientation in <NUM>-<NUM> hours as compared to the process described in International Patent Application No. <CIT> (<CIT>), where the concrete pole made with identical parameters was maintained in a substantially vertical orientation of <NUM>-<NUM> hours before it could be transitioned. As would be appreciated, the storage of poles in a vertical orientation is less cost effective than storing the poles in a horizontal configuration where they can be conveniently stacked on the ground.

For final curing, the concrete pole <NUM> is steam cured in a larger chamber consisting of separate insulated chambers to prevent temperature loss during the loading and unloading of poles. The steam lines provide steam to each of the chambers controlling the rise and fall in humidity and temperature of each individual chamber so poles can be steam cured for a predetermined period of time. Once the pole has been steam cured, the pole is lifted to be stored in storage racks for a further <NUM> hour curing or setting period at which point the pole can be finally cleaned and go through a final quality inspection.

As would be appreciated, the adoption of a mould liner provides a number of significant advantages over prior fabrication processes. As discussed above, use of the mould liner <NUM> decouples the exact state of the concrete from the stripping process making this process much less dependent on operator judgement. This makes it much easier to batch the fabrication process as the mould liner <NUM> and contained concrete pole <NUM> combination may be removed from the fabrication assembly <NUM> after a predetermined duration independent of the exact strength of the concrete. This decoupling also results in the fabrication process being much less sensitive to process parameters such as dependency on temperature. As a result, the requirement for ancillary equipment to maintain temperature during the fabrication process such as equipment to heat or chill water or aggregates is greatly reduced.

Additionally, concrete poles tested for their hardness performance at <NUM> days following casting were found to have an increased hardness, again with identical process parameters. Additionally, the Applicant has found that cracking in the concrete article has been substantially eliminated. It is hypothesised by the Applicant that the continued presence of the mould liner layer following stripping of the outer mould assembly <NUM> maintains the moisture in the concrete allowing for increased thermal conductance from the hot air vapour during the initial curing process and further holds the concrete in a state of compression resulting in improved strength and long term durability.

As the mould liner <NUM> can be fabricated to a high dimensional tolerance and in effect functions as a moulding layer during the casting process, the tolerances and sealing requirements of the outer mould assembly <NUM> can be reduced as the outer mould assembly <NUM> does not need to form the pressure vessel to contain the forces of the concrete pumping and the increasing head pressure during the casting process.

In addition, the complex and costly mechanism required to first support the cylindrical mould portions <NUM> and which is then required to open the mould portions <NUM> in a direction that maintains the individual mould portions <NUM> both parallel and horizontal with respect to each other in the stripping process so as not to damage the uncured concrete pole <NUM> is now not required. This is because the concrete pole <NUM> is now contained by the mould liner <NUM>. As such, the outer mould assembly <NUM> functions as a mould liner support structure, where the configuration of the mould liner may be varied for the same outer mould assembly <NUM> as will be described below.

Referring now to <FIG>, there are shown exploded and assembled perspective views of an outer mould assembly <NUM> incorporating a mould liner <NUM> according to a further illustrative embodiment. In this example, mould liner <NUM> is configured to produce a concrete pole having a smaller diameter than that determined by the inner surface <NUM> of the semi cylindrical mould portions <NUM> of the outer mould assembly <NUM>. In this illustative embodiment, mould liner <NUM> is once again configured as an open-ended tapered sleeve or sock portion but further includes a mould assembly interface arrangement <NUM> that interfaces between the mould liner <NUM> for moulding a concrete article having a first configuration as compared to the outer mould assembly <NUM> which has a configuration for moulding a concrete article of a different configuration. In the case of a hollow concrete article a further core assmbly such as described above (not shown) would be adopted.

In this illustrative embodiment, the mould liner <NUM> is for moulding a concrete article having a different diameter and degree of taper as compared to what would be moulded by the outer mould assembly <NUM> in the absence of mould liner <NUM>. In this illustrative embodiment, mould assembly interface arrangement <NUM> comprises two opposed semi cylindrical interface portions 620a, 620b each having a longitudinally extending liner receiving portion <NUM> and a number of longitudinally spaced annular support or bracing discs <NUM> extending radially outwardly from the liner receiving portion <NUM> and whose outer diameter <NUM> matches the inner diameter of the inner surface <NUM> of the closed outer mould assembly <NUM> at respective locations along the mould assembly <NUM>.

In this example, the outer diameter <NUM> of each interface portion 620a, 620b tapers inwardly moving down the outer mould assembly <NUM> in order to match its degree of taper but in this example the degree of taper of the liner receiving portion <NUM> is greater. As would be appreciated, mould assembly interface arrangement <NUM> may be configured so that the moulded concrete article has no taper or alternatively the same degree of taper as the outer mould assembly <NUM>.

While in this illustrative embodiment, mould assembly interface arrangement <NUM> includes annular support discs <NUM> it will be appreciated that other support or bracing arrangements that transfer the radial compressive forces from the outer mould assembly <NUM> during casting to the liner receiving portion <NUM> are within the scope of this disclosure. In this manner, the outer mould assembly <NUM> which is a large scale heavy structure consisting in one embodiment of steel sections of <NUM> thickness may be used to fabricate poles of many different configurations through the combination of interface arrangement <NUM> which can be configured to be relatively lightweight (eg, steel sections of <NUM>-<NUM>) and swappable within the outer mould assembly <NUM> and mould liner <NUM>.

In this arrangement, interface arrangement <NUM> functions to maintain or mould the shape of the mould liner <NUM> which in turn functions to provide a containment layer to enclose the concrete during the casting proces. As a result, neither the outer mould assembly <NUM> or the interface arrangement <NUM> are required to be sealed together as the mould liner <NUM> performs this function by containing the concrete during the casting process.

Referring now to <FIG>, there are shown exploded and assembled perspective views of an outer mould assembly <NUM> incorporating a mould liner <NUM> according to a further illustrative embodiment. In this example, mould liner <NUM> is configured to produce a concrete pole having a larger diameter than that produced by the mould liner <NUM> illustrated in <FIG>. Similar to mould liner <NUM>, the mould assembly interface arrangement <NUM> comprises two opposed semi cylindrical interface portions 720a, 720b each having a longitudinally extending liner receiving portion <NUM> and a number of longitudinally spaced annular support or bracing discs <NUM> extending radially outwardly from the liner receiving portion <NUM> and whose outer diameter <NUM> matches the inner diameter of the inner surface <NUM> of the closed outer mould assembly <NUM> at respective locations along the mould assembly <NUM>.

As would be appreciated, and as discussed above, the same outer mould assembly <NUM> having reduced sealing requirements and larger tolerances may be employed to manufacture a number of different types of concrete articles as a result improving efficiency and reducing costs. While, the above described outer mould assemblies <NUM>, <NUM> are tapered, costs can be further reduced by making these of a simple cylindrical configuration and yet this arrangement can still be used to fabricate tapered articles as required by varying the mould assembly interface arrangements as required.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge.

Claim 1:
A fabrication assembly (<NUM>) for fabricating an elongate concrete article (<NUM>) in a substantially upright configuration, including:
a core assembly (<NUM>);
an outer mould assembly (<NUM>) defining a mould cavity (<NUM>) between the core assembly (<NUM>) and an inner moulding surface (<NUM>) of the outer mould assembly (<NUM>), the outer mould assembly (<NUM>) being separable following casting of the elongate concrete article (<NUM>) to strip the outer mould assembly (<NUM>) from the elongate concrete article (<NUM>);
a mould liner (<NUM>) forming an intermediate layer between the inner moulding surface (<NUM>) of the outer mould assembly (<NUM>) and the elongate concrete article (<NUM>) being cast, the mould liner (<NUM>) on stripping of the core (<NUM>) and outer mould assemblies (<NUM>) forming an outer containment layer to the elongate concrete article (<NUM>) to form a mould liner (<NUM>) and contained elongate concrete article combination (<NUM>), wherein the mould liner (<NUM>) comprises two opposed longitudinal straps (<NUM>) extending from a top of the mould liner (<NUM>) for removal and transport of the mould liner (<NUM>) and contained elongate concrete article combination (<NUM>) in an upright configuration from the fabrication assembly (<NUM>); and
a concrete mix input assembly (<NUM>) for introducing a concrete mix into the mould liner (<NUM>).