Patent Grant
8627627
This is a 371 of PCT/AU2009/001376, filed Oct. 19, 2009, which claims priority to Australian patent application No. 2008905398, filed Oct. 17, 2008, the disclosures of which are incorporated herein by reference in their entirety and made a part of this application.
This invention relates to concrete casting elements for concrete expansion joints. The invention has particular application to concrete casting elements for assisting in the forming of concrete slabs requiring expansion joints. However, the invention is not limited to this field of use.
When a concrete casting is poured, especially in the case of castings larger than a particular size, several castings are required to be made in succession. In each casting, cracks normally form after setting of the concrete as the concrete cures due to unavoidable shrinkage in the concrete. Because all castings shrink overall, adjoining castings are normally provided with an expansion joint. In order to produce slabs which are durable and functional, some elements which may be used to provide the formwork and the like become embedded in the concrete slab, and other elements are arranged outside the formwork and may be re-used in subsequent concrete castings. For convenience, in this specification, the term casting elements is to be taken to include all elements in or associated with the casting unless the context indicates otherwise.
One of the functions of casting elements is to provide for the placement of other casting elements within the concrete slab and/or expansion joint elements about the periphery of the slab at an elevation above the base of the slab. For example, casting elements known as bar chairs are used for the placement of reinforcing mesh and/or reinforcing bars in spaced relationship above the bottom of the slab so that in the cast concrete slab, such reinforcing is embedded inward by a predetermined spacing from the outer surfaces of the slab. Whilst bar chairs perform this function adequately, there are sometimes circumstances where the fixed height of bar chairs and/or their particular configuration make them unsuitable for spacing casting elements above the base of the slab, even if the other casting elements include reinforcing bars.
Concrete slabs generally, and roadways in particular, are difficult to seal properly against the elements. The simplest way of making expansion joints is to first pour a whole concrete slab and then, as setting has begun, divide it into smaller sections separated by grooves saw-cut on the surface of the slab by means of a diamond-blade saw. Subsequent contraction cracks will then appear at the grooves. The edges of saw-cut expansion joints are prone to crumbling and chipping, so they are not suitable for some applications. Saw-cutting the expansion joint adds to the cost on construction. It is normally important that such joint be sealed against moisture and flooding to avoid erosion of the substrate or foundation by insertion of a sealant into the joint.
Sealants are not usually installed in concrete slabs until such slabs are 28 days old because concrete shrinks while curing, most shrinkage occurring in the first 28 days from casting. This can result in joint opposing faces becoming contaminated and hard to adhere to. Construction timetables can be difficult to maintain, particularly if weather conditions do not leave the job in a dry condition required for continuation.
Shrinkage can occur after placing sealant and for twelve months or longer after the initial casting. Although sealants are designed to expand and contract, there is a mechanical limit to the extent of expansion. For example, 2 mm of shrinkage in a 10 mm wide joint would result in sealant failure. Moreover, if sealants are left in extension for an extended period of time, the sealant may also fail. One approach has been to make contraction cracks wider so that the proportionate expansion of the crack is less. For example, cracks up to 20 mm wide have been tried, but these do not always work. Moreover, such wide contraction cracks and expansion joints may result in a surface unsatisfactory for wheeled vehicles travelling across the expansion joint.
Conventional expansion and construction joints are traditionally made using timber former to form an edge. After pouring, screeding and sometimes further shaping the concrete into its final form, the concrete is allowed to set. The form work is removed some time after setting of the concrete. Once initial shrinkage has taken place the joint former, for example, styrene or other flexible foam joint expansion material, such as Ableflex® brand elastomeric adhesive is glued to the edge. Then the second slab is placed using the concrete upper edge of the previously cast slab as an aid or guide for screeding the next slab. After 28 days the styrene is removed and the joints are sealed with a flexible sealing agent.
The casting element often used for expansion joints may be referred to as an expansion joint element and is typically formed from metal sheeting with a channel running its length. The channel provides a corresponding ridge on the face of the sheeting opposite the channel. Of course, instead of a channel, one or more concavities of other form may be formed into one or both faces, each concavity thus forming a corresponding convexity protruding outward from the opposite face of the sheeting, so long as the concavities and convexities permit the adjoining edges of cast concrete slabs to move towards and away from one another in substantial alignment with their general planarity. In this specification, unless the context indicates otherwise, the term key former will be used to refer to such expansion joint elements.
Expansion joints formed with a key former still have problems associated with sealing. For example, the key former can interfere with the installation of a sealant in a number of ways. An expansion joint caused solely by the shrinkage of concrete may be too narrow for a sealing agent to be installed, with the result that the expansion joint may not be watertight.
In this specification, terms indicating elevational disposition such as upper, lower, top, bottom, horizontal and vertical may be used to refer to features, parts, portions or the like of the casting elements in their normal orientation, and are not to be taken to limit the use of the casting elements of the present invention to any particular orientation, whether or not in use.
The present invention aims to provide one or more types of concrete casting element which alleviate one or more of the problems associated with concrete castings. Other aims and advantages of the invention may become apparent from the following description.
With the foregoing in view, this invention in one aspect resides broadly in concrete casting elements for forming an expansion joint in concrete including:
a pair of expansion joint members each having
the flanges of each one of the expansion joint members being formed to engage one with the other;
the flange of one joint member at least partly overlying the flange of the other to provide an expansion joint upper face and such that the remaining portions may be spaced from one another when the flanges are so engaged;
the flange of the other expansion joint including a lip formed to be substantially coplanar with the expansion joint upper face; and
the flanges also being formed and positioned for protection of the gasket against damage.
In such form, the flanges may slide against one another face-to-face to accommodate the joint members moving towards and away from one another. Preferably, the retainer mounting means is formed as a groove, slot or channel, hereinafter termed a retainer channel, into which a complementary retainer mounting formation may be inserted. The form and/or orientation of the retainer channel are selected to limit the movement of the retainer element towards and away from the expansion joint member whereby the retainer element may retain the expansion joint members in substantially fixed disposition in a concrete slab into which the retainer element is be cast.
In another aspect, the present invention resides broadly in concrete casting elements for forming an expansion joint in concrete including:
an expansion joint recess member having
an expansion joint flange member having
a mounting groove extending along an edge of either or each of the expansion joint socket member and expansion joint spigot member for mounting either expansion joint member to a side edge of a key former,
the flange being formed to have a cross-section complementary to the elongate recess whereby the flange may be inserted into and withdrawn from the recess as the expansion joint members move towards and away from one another in a substantially parallel relative disposition with respect to one another.
In such form, and the expansion joint flange member constitutes the other expansion joint member having the lip substantially coplanar with the expansion joint upper face.
In another aspect, the present invention resides broadly in concrete casting elements for forming an expansion joint in concrete including:
an expansion joint recess member having
an expansion joint flange member having
a mounting groove extending along an edge of either or each of the expansion joint socket member and expansion joint spigot member for mounting either expansion joint member to a side edge of a key former, and
a substantially straight edge formed along either or both the joint recess member and the joint flange member at a disposition suitable for use as a screed rail.
In another aspect, the present invention resides broadly in concrete casting elements for forming an expansion joint in concrete including:
an expansion joint recess member having
an expansion joint flange member having
a mounting groove extending along an edge of either or each of the expansion joint socket member and expansion joint spigot member for mounting either expansion joint member to a side edge of a key former, and
a sealant receiving formation extending substantially along the joint recess member and the joint flange member in respect of which a water-expandable sealant may be received to be operatively disposed in the expansion joint.
Preferably, the recess portion is formed from a pair of opposed flanges, an outer flange and an inner flange, each substantially parallel to the other. In such form, the outer flange corresponds to the flange described with reference to the pair of expansion joint members. The inner face of the outer flange of the expansion joint recess member thus is engageable with the outer face of the flange of the expansion joint flange member. However, in a preferred form, the inner flange of the expansion joint recess member includes a gasket mounting formation to which a gasket may be mounted for sealing the joint.
It is also preferred that the retainer mounting means be formed as a retainer channel as hereinbefore described and into which a complementary retainer mounting formation may be inserted. In some applications, it is also preferred that one of the expansion joint members be supported at a predetermined elevation above the concreting base.
In another aspect, the present invention resides broadly in a casting element support assembly for supporting one or more other casting elements at a selectable elevation above the base of a slab including:
a base portion having;
a mounting portion having
the respective formations are arranged such that when the mounting portion is attached to the base portion, it is also engaged with the base portion is in fixed disposition with respect to the base portion.
Preferably, the attachment formation and complementary attachment formation provide for an interference fit of the complementary parts, such as spigot and socket, tongue and groove, flange and channel or such like. Preferably, the attachment formation is in the form of a channel having a lipped opening, and the complementary attachment formation is in the form of a lipped flange, the lips of the opening and the flange being sized for an interference fit. In such form, lips of the channel and flange are arranged such that the flange is retained in the channel when so inserted.
Preferably, the engagement and complementary engagement formations include complementary keyed faces, hereinafter termed engagement faces, such that when the mounting portion is attached to the base portion, their respective keyed faces engage face-to-face. The complementary keyed faces are formed such that the mounting portion cannot slide along the side of the base portion when the mounting portion is attached to the base portion.
In a preferred form, the complementary keyed faces include a plurality of ridges and grooves of complementary cross-section running orthogonally to the channel and flange of the attachment formation and complementary attachment formation. The mounting formations or formations on the mounting portion may thus have another casting element, such as an expansion joint member hereinbefore described mounted thereto at a selected position above the base of the casting.
In order that the invention may be more readily understood and put into practical effect, one or more preferred embodiments of the present invention will now be described with reference to the following drawings, and wherein:
The casting elements for an expansion joint shown generally at 10 shown in
The provision of the displaced portion permits the left hand and right hand portions of the concrete slab to move towards and away from one another whilst remaining in substantial alignment with one another in their dominant plane. The lower lip of the key former is normally placed on the bottom of the form work into which the concrete is cast to form the concrete slab. Reinforcing bars 30 are embedded in the concrete slab in the form of a reinforcing wire mesh. Reinforcing bars may be provided penetrating through the key former to extend into adjoining castings, known in the art as dowel bars. One or more penetrations are provided through the sides of the channel to permit a bar to be inserted through the channel, transverse to same, thereby permitting the key former to be positioned at a desired height in the casting.
The spigot and socket members each include a slot 19 extending up into the underside of the respective members for engaging with the upper lip 21 of the key former 13. In the example shown in the drawings, the key former is engaged in the slot of the socket member 11. Each member also includes a side web 29 extending vertically upward to provide a side passage 27 closed at the top and bottom and being narrow across, about the same in width as the width of the side web. An inside web 29a is provided substantially parallel to the side web to provide the inside wall of the side passage. Some of the elements described in respect of the spigot member will likewise be found on the opposite side of the socket member and vice versa. For clarity, however, not all of the reference numerals for such portions are provided in the drawings to avoid cluttering of the drawings.
The spigot member 12 includes an under flange 15 extending towards the socket member substantially horizontally in its normal orientation and placement in relation to the socket member. In similar fashion, the socket member includes a top flange 14 extending towards the spigot member. The under flange of the spigot member slides under the top flange of the socket member, the upper face of the under flange sliding under the lower face of the top flange. A socket is effectively formed between the underside of the top flange and the remainder of the socket member. The top flange extends towards the spigot member when the socket and spigot members are in their engaged disposition with respect to one another. The under flange has a proximal lip 16 extending along its proximal edge and extending upward to the same level as the upper face of the top flange.
An optional casting seal 24 is interposed between the main webs of the spigot and socket members, the casting seal normally breaking, as shown, after expansion of the joint due to the expected shrinkage of the concrete after casting. A further optional seal 25 is provided between the lower extremities of the spigot and socket members, again shown in a broken condition due to the expected shrinkage of the concrete after casting.
A strip of sealing tape 37 is provided and bonded into place along its edge portions to the spigot and socket members by a bonding agent. The sealing tape is a strip of flexible material that is chemical and heat resistant. The two parts are provided to permit assembly of the joint members including the installation of the sealing tape. The optional casting seal and further optional seals are formed from a hydrophilic material selected for desirable properties in sealing a concrete crack including materials known in the art. The material selected is coated with a temporary hydrophobic coating formulated to dissolve, dissipate or disperse after a predetermined elapse of time after the installation of the cracking strip in a concrete slab.
The casting elements for the alternative expansion joint 40 shown in
The alternative expansion joint also includes a hollow gasket 17 mounted above the further optional seal between the folds of material forming the remainder of the apparatus. The hollow gasket may be formed from swellable material. Additionally, or on the alternative, a swellable material may be introduced onto the hollow bore extending through the hollow gasket.
Each member is also provided in two parts, an upper part 33 and a lower part 34. As in the case of the expansion joint shown in
An anchoring element 26 is divided from the body of the expansion joint members as shown in particular in
Detail of the engagement of the upper and lower parts of the alternative spigot and socket members is provided in
The anchoring element is retained in place by an edge flange 41 and a locking flange 42 which engage with a tapered flange 43 extending upward and running along the edge of the lower portions of the spigot and socket members. The tapered flange locks in between the edge and locking flanges of the anchoring element, but also, the face of the distal flange facing the spigot or socket member engages with the outer face of the upper portion or the socket or spigot member, as the case may be, thereby locking the upper and lower portions together.
In the expansion joint formed from sheet metal 62 shown in
The socket and spigot members have a single side web 37a from which the top and under flanges extend, the single side web stepping inward at a slanting step 31 to extend downward to a lower fold 33a. The lower fold is 180°, the sheet metal extending upward to provide an inside web 35. The sheet metal is further folded to provide an angle flange 39a for retaining the temporary seal.
A comparison of an expansion joint is shown in
The alternative expansion joint 64 shown in
The further alternative expansion joint 84 shown in
In construction of form work, sometimes wooden beams or members are used to support other casting elements. The nail clip 50 shown in
Instead of being anchored by embedding in concrete, the nail clip may be nailed to a wooden casting element 44 by nails 47 or other fasteners through each of the two nail slots 52. The complementary slot is provided in a connecting formation supported above the base by three triangular webs 48. The expansion joint is mounted to the nail clip by inserting the mounting formation through an anchoring formation slot 49 formed by bending the anchoring formation out from the body of the spigot or socket member—the socket member in the example illustrated in FIG. 21—and engaging the mounting lip in the side passage 27.
A corner channel 58 runs along the outer lower corners of each of the spigot and socket members, similar in dimensions to the distal channel 67 of the closing flange 66, for receiving a corner gasket 59 of swellable material. The swellable material is made to swell by contact with water after setting of the concrete of the adjoining slabs. The gaskets have a coating designed to be eliminated by the setting of the concrete, exposing the material for contact with water, thereby effecting sealing of the joint against transport of water across the expansion joint.
The form setter 160 shown in
On each of the elevation element and mounting portion there is provided a washboard face 156. The washboard face comprises a plurality of ridges and valleys of substantially V shaped cross section running laterally across, the washboard face of the mounting element being of complementary configuration to the washboard face of the elevation element. The mounting portion also includes a pair of edge flanges 157 each of which has a distal lip 159 of larger dimension. The elevation element includes complementary edge slots 158 of equivalent spacing and dimensions to the edge flanges. Each edge slot and has a complementary basal expansion of similar configuration to the distal lip.
The distal lip is of larger dimension than the remainder of the edge flange so that when the mounting element is mounted to the elevation element, it snaps into place at a selected relative axial displacement, or elevation along the elevation element. When so placed, the mounting element is held against sliding axially along the elevation element by virtue of the engagement of the complementary configurations of the opposed washboard faces on each of the mounting element and elevation element. In other words, the ridges of the washboard face of one of the elements engage with complementary valleys of the washboard face of the other element.
In use, the casting elements of the present invention may be used in casting slabs of concrete to provide an expansion joint, including, if required, on site nailing or fixing the casting elements to the remainder of the form work. For longer joints, lengths of the casting elements may need to be joined. A small amount of sealant adhesive, normally a formulation in the form of a paste which can set to form the sealant itself, may be applied to one end of each section of pre-cut sealant to which it would bond, to provide for joining casting elements end-to-end. The expandable tape is provided to overlap the tape of the adjoining casting element to facilitate a continuous seal along conjoined sections of expansion joint. This then becomes a screed rail. Expansion and construction joints received very little longitudinal movement. The use of the invention can provide for the concrete being available for use about 48 hours after completion as against at least one month for conventional methods.
In order to install the casting elements of the present invention, the key former is connected to one of the expansion joint members, usually the socket member, but not necessarily so. The displaced portion has its convex side directed into the casting and away from the other expansion joint member. In order to set the form at the appropriate elevation above the base of the concrete casting, the mounting portion is fixed to the expansion joint member which is not attached to the key former and once the elevation of the form work is set, the mounting element may be attached to the support base by clipping into place so that the respective washboard faces of each element engage. At the same time, the lower lip of the key former is engaged in a lower clip 61 extending from the base of the elevation element in the opposite direction from that of the support strut. The casting elements according to the invention permit, inter alia, the key former to be precisely located at a desirable position, a screed rail for accurate forming of the upper surface of the slab, and a straight edge to the casting.
The concrete slab may be cast with the casting elements in place, and remain embedded in the concrete. The hydrophilic strip is coated with a temporary coating which when dissolved permits moisture to be absorbed, thereby causing the hydrophilic strip to expand into the expansion joint to seal same. The dissolution or disintegration of the coating may occur as a result of exposure to water after setting of the concrete, and/or as a result of the exposure to water used in the concrete mixture which ultimately sets to form the slab. It will be appreciated that expansion joints may be formed using the casting elements of the present invention without a key former.
Although the invention has been described with reference to a range of specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in other forms within the broad scope and ambit of the invention as herein set forth and defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008905398 | Oct 2008 | AU | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/AU2009/001376 | 10/19/2009 | WO | 00 | 4/18/2011 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2010/043003 | 4/22/2010 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3296762 | Thom | Jan 1967 | A |
| 3421267 | Reiff et al. | Jan 1969 | A |
| 3474589 | Cheatwood | Oct 1969 | A |
| 4904111 | Weisbach | Feb 1990 | A |
| 5918428 | Hough | Jul 1999 | A |
| 6598364 | Jones et al. | Jul 2003 | B1 |
| 7845131 | Hough | Dec 2010 | B2 |
| 20080072504 | Hough | Mar 2008 | A1 |
| Number | Date | Country |
|---|---|---|
| 200189350 | Nov 2001 | AU |
| 19722028 | Dec 1998 | DE |
| 1187498 | Apr 1970 | GB |
| 1485950 | Sep 1977 | GB |
| 2006057411 | Mar 2010 | JP |
| WO9001600 | Feb 1990 | WO |
| WO2007021078 | Feb 2007 | WO |
| Entry |
|---|
| International Search Report and Written Opinion completed Feb. 23, 2010 and mailed Mar. 9, 2010 by the Australian Patent Office in counterpart international application No. PCT/AU2009/001376. |
| International Preliminary Report on Patentability issued Apr. 19, 2011 by the International Bureau of WIPO in counterpart international application No. PCT/AU2009/001376. |
| Number | Date | Country | |
|---|---|---|---|
| 20110225919 A1 | Sep 2011 | US | |
| 20130232901 A2 | Sep 2013 | US |
