GB2488685A - Method of adapting a pavement - Google Patents

Abstract

The method, primarily to facilitate drainage, comprises forming a geometrically regular void in the wearing surface layer 1 of a pavement to expose the bedding layer, covering the bedding with a holding plate that has an aperture to allow a cavity-forming device to be introduced, forming a cavity in the bedding layer through said aperture and placing a cavity-adapting element in the cavity. The walls of the void are preferably lined with a former to inhibit lateral movement of the wearing surface. A surface plate may be placed on the wearing surface. The pavement may comprise modular elements or be formed from a continuous laid medium such as asphalt, concrete or a rubber composition. The cavity may be formed in the bedding layer and a substratum layer and may be adapted with a perforated pipe 13, granular elements or concrete. Also claimed is a pavement adapted according to the method.

Description

METHOD OF ADAPTING A PAVEMENT

FIELD OF INVENTION

This invention relates to pavements and more particularly those which are surfaced either with modular elements such as paving blocks, or with a set, continuous paving medium such as asphalt or concrete. The invention relates to the process of the adaptation of such pavements by geometrically regularly opening the surface zone, allowing the provision of deep cavities in the sub-strata, for example for use as local soak-away points to enhance sustainable urban drainage, or for use in locating posts.

BACKGROUND TO THE INVENTION

Despite the considerable utility of hard landscaping, its low ability to handle heavy rainfall has caused public concern. Despite the installation of plumbed drainage systems in such pavements, the low infiltration rate of rain to the underlying soil and the low soaking capacity can lead to severe run-off during heavy rain. This surface water can result in drainage systems and rivers being overwhelmed. Flooding then results.

The block paving industry has been adopting measures to promote sustainable urban drainage. This has been encouraged by UK government bodies such as, in England, The Environment Agency which in conjunction with the Department for Communities and Local Government has published "Guidance on the permeable surfacing of front gardens" (September 2008).

Planning guidelines in England have changed to discourage the use of impermeable pavements in newly built or renovated environments.

Other paving materials are widely used in pavements such as hot or cold asphalt and wet-laid concrete. These are also used for driveways, street walkways, cycle-ways, platforms and roads. Again, rainwater run-off is a potential problem because of their impermeability.

Laying asphalt has proved to be a very widely used medium for the continuous surfacing for pavements. It is more recently available in impermeable and permeable forms. If the permeable form is used, then the permeability of the pavement is dependent on the type of asphalt. The parameter is set.

With modular block pavements and continuous pavements, any given pavement will have a fixed infiltration rate which applies across it, assuming a uniform thickness and uniform sub-strata. It is not readily variable. This means that many old pavements cannot be improved with the present state of the art.

Replacement is expensive and impractical.

Other materials such as epoxy resins and rubber compositions are used as final surfacing on a fine sub-grade, for example to prevent skidding or to act as impact absorbers in playgrounds.

Pavements comprise the wearing course such as paving blocks, set concrete or asphalt and the prepared bedding layer or layers which rest on the land.

Pavements surfaced with a continuous paving medium are different from arrayed pavements where modular elements such as clay or concrete blocks are laid in a closed up pattern. With paving blocks, the pattern is inherently discontinuous because of the separation of the modular elements by gaps.

In contrast, continuous medium pavement surfaces are made by spreading an unset paving composition over a prepared bed to form a continuous surface that then sets. If asphalt, this is finished by rolling or the like. If the surface is wet concrete, it is finished by using a tamping beam or the like.

Whatever the degree of permeability of any continuous pavement, the parameter is set for that laying. The permeability of modular pavements is also set by the choice of blocks.

Both continuous-medium and modular-block pavements are often laid on bedding layers of compacted granulated material that are selected in accordance with the permeability of the paving layer and nature of the pavement. The bedding and any additional sub-grade layers lie on land and form the sub-strata to the pavement.

Modular paving is based on the use of sets of modular blocks laid closed-up in geometrical patterns. Blocks, also known as payers, have top and bottom faces that are principally parallel, allowing for any peripheral round ings. Typically, they are from 5cm to 10 cm thick.

The top surface is the visible, wearing surface. The bottom surface lies on the bedding layer of compacted sand or a light mortar The sidewalls of blocks are generally vertical and often generally planar, though some are convoluted or nibbed, in order to facilitate their laying and sometimes to allow greater permeability of the pavement to rainwater for sustainable drainage. Sometimes the shapes of blocks are geometrically simple though complex interlocking forms are known, as other tessellations.

The most common blocks are approximately rectangular parallelepipeds and cast from concrete. The dimension of the top face is typically 20cm by 10cm nominal. They are commonly from 5cm to 10cm thick with any pavement usually having just one thickness.

They are often laid in stretcher-bond, herringbone or basket weave patterns on prepared beds such as compacted coarse sand that is Scm -10cm thick.

Sometimes soldier courses are used at the edges. Often the bedding course is laid on a sub-base of 10cm coarser fill, which might lie on further base courses on top of the sub-grade i.e. the prepared land.

Official standards reflect common methods for the making of blocks and the laying of block pavements.

Modular paving blocks are commonly made from cementitious compositions. Blocks can differ in material, texture, colour, shape, dimensions and thickness. The blocks are generally entirely solid, though some kinds of blocks that have through-apertures are known. The apertures are later filled with soil and usually seeded with grass seeds. These very open blocks are often used to boost the performance of lawns for example to allow cars to be supported. In practice, most blocks are used for hard landscaping such as pavements and walkways, and for roads.

Paving blocks are typically laid in a close-packed formation. Spacing between neighbouring blocks is often governed by the provision of vertical nibs or projections on the sidewalls. A nib on one wall will bear on the main wall of another block. This prevents the main faces of the blocks mutually chafing while also providing a space of set gap width for a filling with sand or dry mortar The gaps are functional in that they allow rainwater to permeate through the pavement into the bedding layer A soak-through process is desirable because it reduces the likelihood of surface run-off to drains and, in times of heavy rainfall, the consequent overloading of underground drainage systems. This promotes environmentally sustainable drainage.

Despite the presence of the coarse sand in the gaps, the paved surface can have a lower soaking capacity for rain than is desirable. Even though sand can be free draining, fine particulate debris, moss or plants can reduce the permeability The dispersal rate is low.

Associated with such modular pavements but not part of their modularity can be found U-shaped drainage channels for example cast of concrete or plastic. These might have slotted covers to catch rainwater. Such channels are for conducting water away from the pavement via conduits linked to underground drainage pipes. They are part of a designed drainage system leading offsite to discharge points for example into rivers, commonly by public systems. They are specially designed not to allow water to soak into the adjacent ground. Their walls and bases form an impermeable barrier leading to the drain, preventing local soaking.

The paving industry has seen the introduction of concrete block permeable paving (CBPP) in recent years. Here, alterations, some proprietary, have been made by block makers, to the position of the side walls so that in the modular pavement, there are wider gaps, leading to greater permeability to rain. An example of this is disclosed by D B Comfort, J M Moyes, P A Taylor and C D Downson in W02006046063. This has been commercialised by Brett Landscaping Ltd as "T-flow" paving. It has gaps where three blocks intersect, in the form of an equal arm "V'. The width of a "T-flow" arm is about 5mm.

These wider gaps can also clog with debris, moss or plants such as weeds.

Block pavements have edges. Sometimes kerbstones are cut to keep blocks in position for example around where a tree might be later planted. The contained area might then be filled with soil. Alternatively gravel might be used as a filling.

Concrete kerbing requires a suitable base and their installation is disruptive.

Kerbstones are generally deeper than paving blocks and normally laid on a concrete foundation. This is a common but rather inconvenient process.

Kerbstones restrict the ability of rainwater to shed into the adjacent soil.

There is increasing public awareness of the need to have new technical approaches with a view to facilitating sustainable drainage of hard landscaping and thereby mitigating the possibility of flooding.

It is desirable to have new approach to pavement construction, especially to enhance the ability of the paved area to allow rainwater to pass into the substrata.

It is an object of the present invention to provide a new technical solution to this environmental challenge.

DESCRIPTION OF THE INVENTION

According to the present invention there is provided a method of adapting a pavement, said method comprising a) forming a geometrically regular void in the wearing surface layer of said pavement, thereby exposing bedding for said layer, b) covering said exposed bedding with a holding plate that has an aperture to allow a cavity-forming device to be introduced, said plate acting as a support for the bedding layer surrounding said aperture, c) forming though said holding plate aperture, by means of a cavity-form ing device, a cavity in at least the bedding layer of said pavement, and thereafter d) placing cavity-adapting means in said cavity, such that said pavement is thereby adapted by said cavity-adapting means.

In a preferred embodiment, the method of adapting a pavement can comprise a) forming a geometrically regular void in the wearing surface layer of said pavement, thereby exposing bedding for said layer, b) lining the walls of said void with a former in order to inhibit lateral movement of said wearing surface layer into said void, c) covering said exposed bedding with a holding plate that has an aperture to allow a cavity-forming device to be introduced, said plate acting as a support for the bedding layer surrounding said aperture, d) forming though said lined void and said holding plate aperture, by means of a cavity-forming device, a cavity in at least the bedding layer of said pavement, and thereafter e) placing cavity-adapting means in said cavity, such that said pavement is thereby adapted by said cavity-adapting means.

The cavity can be deep, passing beyond the bedding layers, perhaps a metre or so. The cavity-adapting means can enable a cavity to be used variously as a reservoir for water for a soak-away point, to enable the placing of poles or pillars, or for other adapted purposes.

With a modular concrete block pavement (in which the wearing surface is formed of closed-packed modular elements), the void can be created by removing one modular block (or two or more adjacent modular blocks) from within the body of the pavement, thus exposing the bedding. The void that is created is then lined, perhaps temporarily, with an open-topped and open-based former to keep the adjacent blocks in position.

The walls of the former correspond to the peripheral walls of the block so that it and one block (or two or more adjacent blocks) can be exchanged without affecting the position of the surrounding blocks.

With a continuous laid pavement in which the wearing surface is a continuous paving layer, typically concrete or asphalt, a geometrically regular hole is created for example by a rotary drill such as with a hole or core saw, or with a scribing bit. The inner debris is removed and the void lined with a liner to hold the walls from displacement. The hole can also be created by inserting the former in a larger hole and making good the pavement to the edge of the former.

Holes can also be created in deep gravel in this way.

The former can project above the wearing plane of the pavement. The former can project into and below a bedding layer such as of sand, in order to act as a retaining wall for the sand or other such bedding medium.

The cavity is then created by introducing, into the lined void, the cavity-form ing device such as a rotary auger or a soil punch. The cavity spoil is removed. The cavity can be of any depth, typically up to one metre but, in some cases, more should the ground conditions permit.

Once the cavity is formed, it can be used for various purposes such as a soakaway, to hold a post or pillar, to hold compost for a plant or to hold wet concrete which, when set, acts as a deep foundation.

The lining former used during cavity formation can be replaced with a permanent lining former, perhaps of different material, during the process of adaptation.

The method can be used on a given pavement once or repeatedly. Often the voids will be formed at regular intervals, for example, in a block pavement, by taking out each N-th block to create a regular array of adaptation points.

In particular, in one embodiment of the present invention, there is provided a method of adapting a modular block pavement, said method comprising forming though a modular void formed by a peripherally disposed plurality of such blocks when so laid and when a defining surface of said void is held by holding means, an elongate cavity in underlying sub-strata, said elongate cavity being formed by a cavity-making device, and thereafter placing cavity-adapting means in said cavity, such that said pavement is thereby adapted by said cavity-adapting means.

The exposed bedding layer is covered with a holding plate that has an aperture to allow the cavity-forming tool to be introduced. The plate should be retained against movement while cavity formation is in progress and while the tool is being removed. At this time, the plate acts as a support for the surrounding bedding layer to prevent undue disturbance. The holding plate can be attached to the former and the former attached to a surface plate so that the surface of the blocks around the void is protected from the operation.

The method offers the facility readily to adapt a modular block pavement at an individual point or at multiple points for example to create soak-away points.

The cavities can be also used for other purposes such as for accepting posts.

The modularity of loose-laid block pavements allows the loose-laid modules i.e. blocks, to be readily removed by lifting. The pattern of laying is conducive to the removal of a number of blocks at regular intervals, for example along the edge of a path or drive so creating a number of regularly separated voids.

The method can also be used with modular flagstones.

The method offers scope to pavement owners to create a substantial increase in soakaway capacity with relatively little local disturbance. For example, so long as ground conditions permit, the introduction of a one-metre deep cavity of 7.5cm diameter, lined by a perforated pipe, in a block pavement, using blocks of 20cm long by 10cm wide by 6.5cm deep, creates over 4 litres of instant soakaway capacity at that point. If one hundred blocks are removed in a pavement, perhaps one per square metre, the soakaway capacity rises to 400 litres.

The cavity that is created can be used as a soakaway or for another purpose such as to receive wet concrete for a foundation.

In order to preserve the integrity of laying, the block-sized void is held in shape by holding means that support the blocks flanking the void. The holding means i.e. former, can be a hollow box made of metal, plastic, wood or compressed fibre, having the general dimensions of the sidewalls i.e. perimeter, of a block, so that it can be readily inserted into a void and immediately resist any lateral force of displacement of a flanking block. Holding plates that are individual sections can also be used, rather than a box. A holding plate can flank one block's sidewall or a plurality. A former can be 20cm long by 10cm wide and from Scm to 30cm deep, for use with a pavement made of closed-up, loose-laid paving blocks having a nominal wearing surface of 20cm x 10cm.

The use of holding means i.e. a former, is usually necessary during repeat operations to avoid the inconvenience of adjacent blocks displacing.

The base of the void created by the removal of one or more blocks i.e. the bedding layer, can be covered with a plate. This can have a circular or other shaped aperture to allow the cavity-forming tool to pass through and so preserve the bedding layer from undue disruption except where cavity formation occurs.

Thus, a defining surface of the void can be the base i.e. bedding, of the void and the holding means can be a steel, plastic or wooden plate which is located on the bedding so that it is not unduly disturbed around the cavity during cavity formation.

The above method can be extended by first removing a block from a section of intact block pavement, thereby creating a modular void, and then inserting holding means.

The method enables both mature pavements and new pavements to be adapted.

The basic method can also be extended by first laying the block pavement using holding means that is a mod ularly shaped wall former to create the modular void when the pavement is laid around it. This enables the block-sized voids to be created during the laying of a pavement whether on first laying or when there is local lift-and-relaying procedure for the blocks.

Subject to ground conditions, the elongate cavity can be formed by augering the sub-strata using an auger, by drilling the sub-strata using a core drill, or by punching the sub-strata using a punch. The cavity is likely to be cylindrical. Care must be taken when withdrawing the material from the ground when the cavity is being formed, so that the bedding layer is not unduly disturbed outside the area of the cavity.

Thus, an apertured ground-plate liner for the base of the void and to hold the bedding, can be inserted with flanges extending over the surface of the pavement. If wide lateral plates are employed, the lateral flanges can be held by the operator's weight and the augering cleanly done through the aperture in the bedding liner.

The flanges can instead be in the form of a surrounding plate, so that the soil can be collected without staining the adjacent paving material. This plate can also act as a platform.

A surround plate with an open central section that is the size of a block and with walls extending from there on the plate to form a hollow block with a surround can be used as a template for repeated operations.

This means that once the first void is present, the box section of the template can be fitted into the void to hold the adjacent blocks against displacement. The first void is formed either by removal of a block from an existing pavement or by locating the template on the bedding where void is to be present and placing blocks in closed-up manner around it, in accordance with the laying pattern of the pavement at that place.

The template can act as a platform and surface to collect the spoil, so allowing the underlying blocks to remain clean. Once one cavity is created, the template can be positioned in another void to allow further cavity formation, and the process repeated as necessary over the area of the pavement. Once the template is removed, each void is then lined with a permanent former.

The use of the template streamlines the process of repeated cavity formation over a pavement. For example, in a pavement measuring lOOm by 2m and consisting of 50 blocks per square metre, if two blocks per square metre are removed, this means 400 cavity forming operations. If the reservoir capacity of a soakaway cavity is 4 litres, the pavement is provided with 1600 litres of potential rain sump capacity. This water is dispersed in association with the pattern of soakaway placement, and is normally straightforwardly achievable, if necessary in stages! The alternative method of installing a large sump of 1600 litres capacity would require major engineering work.

In loam or wet clay soil, the process of block removal and cavity formation takes a short time, only several minutes. The cavity can then be immediately lined with a permeably capped perforate tube or charged with gravel, so creating a local soakaway.

The depth of the cavity can be at least equal to the depth of the paving blocks, or at least double, at least treble, at least four times, at least ten times or more. Thus, if the sub-grade (ground) which supports the sub-base and bedding layer for the pavement is soil, a cavity can be a metre or more deep.

The cavity-adapting element for the cavity will vary according to the intended purpose. Thus, the adapting means for the cavity can be granular material such as gravel or coarse sand, to allow a soakaway point. The former-mod ified void can also be charged with gravel or coarse sand.

The cavity-adapting means can at least comprise wet concrete, for example if a post or pole is being inserted in it or if a local foundation is being created for example for a seat. The wet concrete can be filled to the top of the bedding layer and allowed to set. A paving block can be laid on that to disguise the underlying support.

A fastener such as an eyelet, threaded stud, peg, threaded socket, etc., can also be set into the wet concrete to allow an article to be fastened to it when the concrete has set.

The adapting means for the cavity can be a tube, for example to receive a pole or post.

The tube can be smooth walled or of concertina section and it can be perforate, for example made of mesh.

The tube can be offset from the upper cavity to emerge in a nearby void rather than the void over the cavity that can be filled with a paving block.

The cavity-adapting means can be a container that can have a modular horizontal cross-section when installed. This can act as a sump. The cavity can be filled with material such as a growing medium for a plant or wet concrete. The tube or sump container is provided with a cap that is perforate if surface water is to be permitted to enter.

The holding means can be removed once the cavity is formed and a further former such as a walled former having walls matching the sidewalls of a block can be introduced.

As well as the cavity being adapted, the void can be adapted by using void-adapting means. If the cavity is charged with wet concrete up to the top of the bedding layer and this concrete sets, a modular block, perhaps differentiated by colour from the others, can be used to re-instate the pavement at that point. This block is supported by the concrete foundation and is thus more load bearing.

In other cases, the void can be adapted by being charged with wet concrete if the cavity is also filled with wet concrete. This concrete sets to create a plain foundation or for a base for a post, pole or tube set into the concrete when wet In other cases, the void can be filled with gravel if the cavity is filled with gravel or has a soak-tube. In other cases, the void can be filled with a drainage block of modular block dimensions, which can allow surface water to drain through it and down to gravel or a soak-tube underneath.

In other cases, the void can be filled with a growing medium with the cavity similarly filled to allow planting of a plant.

Sets of identically adapted points at regular intervals can work in harness for example to create an array of soak-away points, an array of foundations, an array of posts or an array of plants. The arrays can be one or two-dimensional and members regularly spaced. The process of adaptation is subject to ground conditions and where favourable very versatile.

If the fill for the void is gravel or a growing medium, the permanent former prevents the blocks at the side of the void from displacing laterally and weakening the integrity of the pavement.

Complementing the use of the method for modular paving, the method can be used on continuously laid pavements where the medium, rather than being a concrete or other kind of modular block or modular slab, is continuous such as laid and set asphalt or laid and set concrete.

Here the regular void is created in the layer of set asphalt, set concrete etc., but the process of adaptation of the cavity and void is the same as with the modular blocks as previously described: this teaching is hereby applied to continuous pavements such as of asphalt or a concrete medium.

In particular, in this further embodiment of the invention, there is provided a method of adapting a pavement surface formed from a continuous paving medium laid on a bedding layer, said method comprising forming though a regular aperture formed in said medium and when the defining surface of said aperture is lined by holding means, an elongate cavity in underlying sub-strata, said elongate cavity being formed by a cavity-making device, and thereafter placing cavity-adapting means in said cavity, such that said pavement is thereby adapted by said cavity-adapting means.

Loose asphalt can be laid manually or by a laying machine. Wet concrete can be laid by machine or manually. They are then allowed to set before the pavement can be used.

The regular aperture or void that is created in the continuous surface is of a regular geometrical horizontal cross-section when incorporated in a horizontal pavement. It can be circular, square, rectangular or the like. It can be more complex such as a series of circles on the circumference of a circle.

As the regular aperture has a geometrically regular, cross-section on the wearing surface, the aperture is aesthetically pleasing relative to relative to randomly broken paving medium.

The aperture can be readily lined with a matching cylindrical former if the asphalt or concrete is cut by a core drill. The aperture in an existing pavement can also be formed by a heated core-forming mandrel that can have a square, rectangular, circular or other geometrically regular, cross-section and loosen the asphalt with heat. It can also be formed by chain drilling. Sawing can also be used.

For example, a core of set asphalt or set concrete can be cut by a powered coring saw, the core material removed for disposal and holding means inserted, preparatory to cavity formation. Preferably, the gap between the wall of the core and the liner is less than 2cm, and more preferably less than 1cm.

The method of the invention also envisages forming the aperture in or through an epoxy anti-slip layer on top of a layer of asphalt or concrete.

The method offers the ready facility to adapt an asphalt or concrete pavement at an individual point or at multiple points for example to create soak-away points. The method has two important steps. These are the creation of the regular aperture in the paving medium and thereafter forming a narrower cavity in sub-strata below that aperture.

In other embodiments beyond use as soak-away points, a cavity can be also used for other purposes such as for accepting a post or being filled with wet concrete to form a miniature pier when set.

The method of cavity formation can be repeated along a pavement for example at regular intervals to form an array that can be linear or two-dimensional. The density of the array can be varied across the pavement in accordance with surface water infiltration or other needs.

The continuous paving medium can be laying asphalt, wet concrete or gravel for creating a continuous pavement which can be used for the method. A modular paving block can be a flagstone, A former can be a plain liner, a template former i.e. having a surface plate, or a secondary former replacing the primary former.

A void-making tool or device can be a core drill. A cavity-making tool or device such as a rotary auger. Cavity-adapting means can be a pipe. Void-adapting means can be a modular drainage block.

Also in accordance with the invention there is provided a pavement such as comprising modular blocks or a continuous paving medium adapted according to said method.

A modular block pavement or a continuous laid pavement can be adapted by forming though a former-lined void, an elongate cavity in underlying sub-strata, said elongate cavity being formed by a cavity-making tool, and thereafter placing cavity-adapting means in said elongate cavity, such that said pavement is thereby adapted by said cavity-adapting means.

The process is undertaken without the use of the lining former. This operation can best be achieved if the bedding layer or sub-strata are firmer than soil and so less likely to break down outside the immediate cavity area and destabilise the adjacent paving medium Once the cavity has been formed, the void can be permanently lined with a former to hold the medium in position. The former engages with the walls of the flanking medium to stabilise it. If the former is of deep-wall section, it can be used to support the sand in the bedding layer against displacement into the sub-void.

The former can have the shape of the sidewalls of the geometrically regular void or can be a cross-member. The purpose of the former is to resist any force of lateral displacement of medium surrounding the void so maintaining the laying.

This method for block pavements can be extended either by first removing a block from a section of intact block pavement, thereby creating said modular void, or by first laying said block pavement so as to create a modular void.

For this embodiment of the method, the depth of the cavity, the method of its formation, the tools and other components, and the nature and use of the cavity-adapting means are as described with the initially described method of the invention.

The method described herein is not restricted to the removal of single blocks at particular points in a block pavement. The method can be used when a group of neighbouring blocks is removed or not first laid, such as two, three, four, five, six, seven or eight blocks, so creating a modular void of larger dimensions than a single block.

Multiple blocks of different nature including shapes or sizes can be removed or not installed, so creating more complex wall shapes for the voids.

The method is very versatile and allows block pavements to be adapted readily to a variety of purposes.

The features of the inventions can be used in any combinations that are suitable for the end purpose.

Some aspects of the invention will now be illustrated by reference to S drawings without limitation of the scope of the invention.

DESCRIPTION OF THE DRAWINGS

Figure 1 represents a view from above of the wearing surface of an adapted modular block pavement having three soak-away points.

Figure 2 represents a vertical cross-section of the pavement of Figure 1, with a paving block removed preparatory to the creation of a soak-away point.

Figure 3 follows from Figure 2, showing the augering of the strata to create a cavity.

Figure 3A is a cross-sectional view of the former of Figure 3.

Figure 4 follows from Figure 3, showing a ducted soakaway point.

Figure 5 follows from Figure 3, showing a gravel-filled soak-away point with a tubular chamber.

Figure 6 follows from Figure 3, showing a concrete foundation in the cavity, again adapting the pavement.

Figure 6A is a cross-sectional view of the former of Figure 6.

Figure 7 follows from Figure 3, showing an anchored eyelet set in concrete, as a fastening point.

Figure 8 follows from Figure 3, showing a tubular support inset into the cavity.

Figure 9, following from a larger cavity than Figure 3, shows the presence of a modular sump.

Figure 10 represents a view from above of the wearing surface of a continuous asphalt or continuous concrete pavement having three soakaway points.

Figure 11 represents a vertical cross-section of the pavement of Figure 10, with a core removed preparatory to the creation of a soak-away point.

Figure 11 A is a cross-sectional view of the former of Figure 11.

in Figure 1, the wearing surface of a modular pavement is formed from a closed-up loose-laid array of paving blocks that are approximately rectangular parallelepipeds (1, only one block numbered for clarity). The pavement is adapted by the insertion of three soakaway points (2,3,4).

At point 2, there is a soak-away container (5) and tube (6) as will be later described, with the perforated cover removed to illustrate the position of the tube.

At point 3, an identical soak-away point has a perforate cover (7) in place.

At point 4, there is gravel infill (8).

Figure 2 shows a cross-section at the start of the making of the soakaway points 2,3,4 along the line X-Y.

The blocks are on a bed (9) of compacted coarse sand on a compacted bed of coarse aggregate. A flanged hollow former (10) is in place. This has the main horizontal cross-sectional area of the removed block and its sidewalls support adjacent blocks to stop them entering the void created by the removed block. The former (10) also cuts into the sand layer to retain it. The former has a base (11) for compressing the top of the bedding layer (9). This base has a substantial circular aperture in the centre to allow the auger bit to pass through.

Figure 3 follows Figure 2 as the cavity is being created by the powered auger (12), with the shaft of the auger passing through the base plate aperture.

The flanges at the side stabilise the steel former (10) and can be stood on by the operator so that the former remains in place when the auger is inserted and later withdrawn with spoil. The base plate of the former prevents the bedding layer from being unduly disrupted by the augering process.

The former is then withdrawn ready for re-use in another position.

Figure 3A shows the former (10) which has a surface plate portion (1 OA) for protecting the pavement surface, a wall portion (1 OB) for inhibiting lateral movement of the adjacent blocks into the void, a base portion (11)for compressing the top of the bedding layer and a projecting wall portion (lOG) of the former to retain the bedding medium.

Figure 4 follows from Figure 3 and shows a tube (13) and forming cavity insert (14) which has been provided. The tubular section (13) is perforate to allow drainage of water and the cap (14) is perforate. The cap also has sidewalls so acts as a former, preventing the lateral displacement of blocks into the void.

Figure 5 follows from Figure 3, as a different variant. Here a perforate tube (15) having a hollow block shaped capping member (16) has been inserted into the cavity. The vertical sidewalls of the capping member (16) act as a former, the void they subtend is filled with gravel (17), and this is made flush with the wearing surface.

Figure 6 follows from Figure 3, where a former with a base (18) has been installed and the cavity and volume contained by the walls of the former have been charged with wet concrete that has been allowed to set so forming a foundation pier (19).

In another embodiment (not shown), a group of regularly spaced and identical piers is installed in the block pavement. The void can be filled with concrete or asphalt while permanently unlined.

The pier can be used for supporting a heavy object.

Figure 6A shows the former (18) which has a wall portion (1 8A) for inhibiting lateral movement of the adjacent blocks into the void, a base portion (18B) for compressing the top of the bedding layer and a projecting wall portion (1 8C) of the former to retain the bedding medium.

Figure 7 follows from Figure 3, where the base former (18) is installed and the cavity filled with wet concrete (20) in a manner similar to Figure 6 except that an eyelet fastener (21) is embedded in the wet concrete to act as an anchoring point when set, for example for a canopy, marquee or animal.

Figure 8 follows from Figure 3, where a collar-like former (22) is introduced into the void. This has a collar portion suitable for receiving a tube (23). A post (24) which has a sign (25) is inserted into the tube and later removed and replaced with another (not shown).

In Figure 9, the cavity is formed by a multiple augering process within the lateral confines of the void, so that a cavity of modular horizontal cross-section is created. After suitable bedding with coarse sand, a sump device (26) having a matching modular cross-section is inserted to the bedding depth. The sump device has a removable perforate cap (27) to allow water to collect.

In Figure 10, analogous to Figure 1, the wearing surface (28) of pavement is formed of continuously laid asphalt or continuously laid concrete. The pavement is adapted by the insertion of three soakaway points (29, 30, 31).

At point 29 which is partially constructed, the core has been formed in the pavement with a wide diameter rotary "tank cutter" scriber or a core drill. Core drills having diameters of 10cm are routinely used in the construction industry to core brick and concrete.

The spoil has been removed and the cylindrical aperture has been permanently lined with a former (32). The cavity is next created within the area defined by the former, by augering into the substrata and a perforated tube (33) is then inserted to the depth of augering, as a soakaway chamber.

At point 30, a similar soakaway point to 29 has the former (32) acting as the housing for a soak block cap (34).

At point 31, a similar soakaway point to 29 has a former (32) and a gravel infill (35).

It is also possible to create an irregular cavity and then to introduce a former and make good the surround so that the template can be introduced and cavity formation then undertaken.

This process of cavity formation can also be done in thick gravel where the former is introduced and the gravel made good around it. The deep cavity is then created as described.

Figure 11 shows a cross-section at the start of the making of the soak-away point 29 along the line A-B The continuous asphalt or continuous concrete (28) is on a bed of compacted open aggregate (36) on a compacted bed of coarser aggregate (37).

A flanged template former (38) is in place. This has a matching main horizontal cross-sectional area to the removed core to allow it to fit. The sidewalls support the adjacent asphalt to prevent it entering the aperture created by the removed core. The former (38) also cuts into the sand layer to retain it. The former has a base for compressing the bedding layer. This base of the template has a substantial circular hole in the centre to allow the auger bit to pass through. The base of the template holds the sides of the bed.

The deep cavity is then formed. The template is removed after augering and a permanent former (32, Figure 10) is inserted. The process then follows that as described for a modular pavement in Figures 3 to 9.

Figure hA shows the former (38) which has a surface plate portion (38A) for protecting the pavement surface, a wall portion (38 B) for inhibiting lateral movement of the adjacent blocks into the void, a base portion (38C) for compressing the top of the bedding layer and a projecting wall portion (38D) of the former to retain the bedding medium.

Though subject to suitable subsoil conditions, the process is very versatile.

It allows previously impermeable pavements to be provided with soakaway capacity.

The drawings illustrate a number of beneficial and relatively simple adaptations of continuous asphalt, continuous concrete or modular element (such as concrete blocks or flagstone) pavements.

Claims (2)

1. CLAIMSI A method of adapting a pavement, said method comprising a) forming a geometrically regular void in the wearing surface layer of said pavement, thereby exposing bedding for said layer, b) covering said exposed bedding with a holding plate that has an aperture to allow a cavity-forming device to be introduced, said plate acting as a support for the bedding layer surrounding said aperture, c) forming though said holding plate aperture, by means of a cavity-forming device, a cavity in at least the bedding layer of said pavement, and thereafter d) placing cavity-adapting means in said cavity, such that said pavement is thereby adapted by said cavity-adapting means.
2. 2 The method of adapting a pavement according to Claim 1, by a) forming a geometrically regular void in the wearing surface layer of said pavement, thereby exposing bedding for said layer, b) lining the walls of said void with a former in order to inhibit lateral movement of said wearing surface layer into said void, c) covering said exposed bedding with a holding plate that has an aperture to allow a cavity-forming device to be introduced, said plate acting as a support for the bedding layer surrounding said aperture, d) forming though said lined void and said holding plate aperture, by means of a cavity-forming device, a cavity in at least the bedding layer of said pavement, and thereafter e) placing cavity-adapting means in said cavity, such that said pavement is thereby adapted by said cavity-adapting means 3 The method of any of Claims 1 and 2, in which said former has a wall which projects beyond said surface layer.4 The method of Claim 3, in which said projecting wall projects into and below said bedding layer, thereby acting as a retaining wall for said bedding.The method of any above Claim, and also placing a surface plate on said wearing surface layer, so that the surface of said pavement around said void is protected during cavity formation.6 The method of any of Claims 1 to 5, in which said pavement is formed of close-packed modular elements, by removing such an element to create said geometrically regular void.7 The method of any of Claims 1 to 5, in which said pavement is formed of close-packed modular elements, by removing multiple elements to create said geometrically regular void.8 The method of any of Claims 1 to 8, in which said pavement is formed of a continuous laid medium, by forming said geometrically regular void in the surface layer of said pavement by using a geometric hole cutter.9 The method of Claim 8, in which said medium is asphalt.The method of Claim 8, in which said medium is concrete.11 The method of Claim 8, in which said medium is a rubber composition.12 The method of any of Claims 1 to II, in which said cavity is formed in a bedding layer and a substratum layer under said bedding layer.13 The method of any of Claims 1 to 12, in which said cavity forming device is an auger.14 The method of any of Claims Ito 12, in which said cavity forming device is a drill.15 The method of any of Claims I to 12, in which said cavity forming device is a punch.16 The method of any of Claims I to 16, in which said cavity is cylindrical.17 The method of any of Claims 1 to 16, in which said cavity-adapting means at least comprises a pipe.18 The method of Claim 17, in which said pipe is perforated.19 The method of any of Claims I to 16, in which said cavity-adapting means at least comprises granular material.The method of any of Claims 1 to 19, in which said cavity-adapting means at least comprises wet concrete which sets in said cavity.21 The method of Claim 20 and incorporating a fastener into the wet concrete to allow an article to be fastened to it when said concrete has set.22 The method of Claim 21, and, when said concrete has set, fastening an article to said fastener.23 The method of any of Claims 1 to 22, in which the depth of said cavity is at least equal to the depth of said wearing surface layer.24 The method of any of Claims 2 to 23, and replacing said lining former with a further former.The method of any of Claims 1 to 24, and adapting said void with void-adapting means.26 The method of any of Claims 1 to 25 and thereafter repeating said method at another place on said pavement.27 The method of any of Claims 1 to 25, and thereafter repeating said method at regular intervals to create a regular array of adaptation points.28 A pavement adapted according to the method of any of Claims I to 27.29 A pavement of Claim 28, in which said pavement comprises a continuous paving medium.30 A pavement of Claim 28, in which said pavement comprises close-packed modular elements.