1. Technical Field
The following relates generally to roadway construction and repair, and more particularly, to the formation, installation and system for replacing and/or intermittent repair of a pre-fabricated pavement slab, and the slab so formed.
2. State of the Art
Many of our vital utilities such as water, sewer, storm and gas lines, telephone and other communication cables, heating and cooling lines are buried underground to keep them out of harm's way and protected from the elements. While many of these were wisely installed outside of highway pavement areas, to facilitate access for repair or replacement purposes, many more were not because there were no available alternative locations.
Under-pavement utilities are particularly common in cities where there is no other space to locate them.
Repair of under-pavement utilities inherently involves removal and replacement of the pavement above the utility. The process typically involves sawing the existing pavement along the boundaries of the trench, removal of the pavement and the earth below it, repair of the utility, backfilling the excavated material and finally, restoring the pavement to its original condition.
Acceptable restoration of pavement over utility trenches in heavily traveled areas, such as city intersections, has been an age-old problem. Not only is the backfilling process often done hastily but the pavement is frequently replaced with “flexible” asphalt pavement. When the poorly-compacted backfill settles, the pavement follows leaving “classic” bumps at such locations.
A proper restoration of concrete pavement that has been removed for utility repair requires insertion of load transfer dowels to transfer load across joints between adjacent slabs of the new concrete pavement. Properly inserting dowels in replacement pavement is a laborious and time consuming process that is sometimes omitted in heavily traveled areas, in the interest of limiting repair time, which omission may result in a concrete “patch” that may, and often does, settle as the newly installed backfill over the utility settles.
An alternative to sawing the pavement for a “specific” trench directly over the utility is to remove entire pavement slabs that have been placed in the general vicinity of the desired trench. This is done by cutting the dowels in the existing joints around the slab or slabs that are to be removed to free it up for removal. Once removed, the utility may be repaired. Prior to installing new cast-in-place pavement the current practice is to drill holes for new dowels in the edges of the surrounding existing pavement with a drill or other boring device. The current practice is to drill holes for the new dowels slightly offset from the original dowels which were cut in half in the removal process and remain in the existing pavement. This time-consuming process is necessary since it is extremely difficult to remove the half of the original, typically solid, steel, dowel. This practice also compromises the structural integrity of the edges of the existing pavement because holes for dowels now exist at 6 inch rather than at 12 inch centers.
Accordingly, there exists a need in the industry for a precast pavement slab and a method of installing the slab that solves these and other problems.
The following relates to roadway construction and repair, and more particularly, to the formation, installation and system for replacing and/or intermittent repair of existing concrete pavement or of a previously-placed pre-fabricated pavement slab, and the slab so formed.
A first general aspect relates to a connector for placement in adjacent pavement slabs, the connector being configured to couple the adjacent slabs. The connector comprises a dowel having an axial opening therethrough, and engagement components fixedly coupled to the dowel within the opening, wherein a portion of the dowel is embedded in one pavement slab and a remaining portion of the dowel is embedded in an adjacent pavement slab.
Another general aspect relates to a first engagement component that may be positioned in the opening such that the first engagement component resides in the portion of the dowel that is embedded in the one pavement slab. A second engagement component may be positioned in the opening such that the second engagement component resides in the remaining portion of the dowel that is embedded in the adjacent pavement slab.
Another general aspect relates to the engagement component being a threaded bolt nut.
Another general aspect relates to the dowel being a cylindrical steel bar having the opening therethrough.
Another general aspect relates to the engagement component being fixedly attached to the opening.
Another general aspect relates to a system for installing and removing a connector in adjacent pavement slabs, wherein the system comprises a connector having an axial opening therethrough and engagement components fixedly coupled to the connector within the opening. The system further comprises a pavement slab, wherein a portion of the connector is embedded in the pavement slab and a remaining portion of the connector is exposed, and an adjacent pavement slab having an interconnection slot, wherein under the condition that the adjacent pavement slab is positioned adjacent the pavement slab, a joint is established therebetween and the interconnection slot covers the remaining portion of the exposed connector. The system further comprises a binder material, the binder material being inserted into the interconnection slot to bind the remaining portion of the connector to the adjacent pavement slab.
Another general aspect relates to a first engagement component being positioned in the opening such that the first engagement component resides in the portion of the connector that is embedded in the pavement slab, and a second engagement component being positioned in the opening such that the second engagement component resides in the remaining portion of the connector that is within the interconnection slot of the adjacent pavement slab.
Another general aspect relates to, wherein under the condition that the pavement slab and the adjacent pavement slab are cut along the joint, the connector is cut into a first half and a second half, wherein the first half of the connector contains the first engagement component and the second half of the connector contains the second engagement component.
Another general aspect relates to, wherein under the condition that the adjacent pavement slab is vertically moved away from the pavement slab, the axial opening of the first half of the connector is exposed.
Another general aspect relates to an engagement mechanism, wherein the engagement mechanism is configured to reach within the exposed axial opening of the first half of the connector to engage the first engagement component.
Another general aspect relates to the engagement between the engagement mechanism and the engagement component facilitating the removal of the first half of the connector from the pavement slab, leaving a space in the pavement slab, the space being defined by the shape of the removed connector.
Another general aspect relates to the engagement component being a coil bolt nut and the engagement mechanism being a coil bolt. As the coil bolt is threaded through the nut, the distal end of the coil bolt contacts a terminal end of the space, which prevents further axial advancement of the coil bolt, which causes the nut and the first half of the connector coupled thereto to axially retreat from the space.
Another general aspect relates to a full replacement connector being inserted and secured within the space, such that a portion of the full replacement connector is embedded in the pavement slab and a remaining portion is exposed.
Another general aspect relates to a method of vertically removing and replacing a pavement slab, the method comprising, cutting along a joint between a pavement slab and an adjacent pavement slab, wherein the cutting along a joint cuts a connector positioned between the pavement slab and the adjacent pavement slab into two parts, vertically removing the adjacent pavement slab to expose the part of the connector in the pavement slab, removing the part of the connector from the pavement slab, installing a new connector in the place of the part of the connector in the pavement slab; and replacing the adjacent pavement slab.
Another general aspect relates to the step of removing the part of the connector from the pavement slab further comprising inserting an engagement mechanism into a central opening in the part of the connector, engaging an engagement component positioned in the central opening with the engagement mechanism, and operating the engagement mechanism to remove the part of the connector from the pavement slab without damaging the pavement slab.
Another general aspect relates to the step of installing a new connector in the place of the part of the connector in the pavement slab further comprising placing a binder material between the new connector and the pavement slab, and inserting the new connector into a space created in the pavement slab by the removal of the part of the connector from the pavement slab.
Another general aspect relates to the step of replacing the adjacent pavement slab further comprising removing the part of the connector from the adjacent pavement slab, cleaning out an interconnection slot in the adjacent pavement slab, and replacing the adjacent pavement slab by placing the adjacent pavement slab with the newly cleaned-out interconnection slots over the new connector in the pavement slab.
Another general aspect relates to the step of the replacing the adjacent pavement slab further comprising installing a new pavement slab in the place of the adjacent pavement slab, wherein the new adjacent pavement slab is configured to couple to the new connectors of the pavement slab.
Another general aspect relates to the step of the engaging an engagement component positioned in the central opening with the engagement mechanism further comprising threading the engagement mechanism into the threads of the engagement component until the engagement mechanism engages the pavement slab and causes the engagement component to axially withdraw down the threads of the engagement mechanism, which in turn causes the part of the connector, which is fixedly coupled to the engagement component, to remove from the pavement slab without damaging the pavement slab.
The foregoing and other features, advantages, and construction of the present disclosure will be more readily apparent and fully appreciated from the following more detailed description of the particular embodiments, taken in conjunction with the accompanying drawings.
Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members.
A detailed description of the hereinafter described embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures listed above. Although certain embodiments are shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of the appended claims. The scope of the present disclosure will in no way be limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc., and are disclosed simply as an example of embodiments of the present disclosure.
As a preface to the detailed description, it should be noted that, as used in this specification and the appended claims, the singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.
Referring to the drawings,
The top surface 9 of the slab 10 may have a roughened astro-turf drag finish, while the sides 11a and 11b, the ends 11c and 11d, and bottom surface 7 of the slab 10 have a substantially smooth finish. The side 11a or the side 11b may be a first edge and the end 11c or the end 11d may be a second edge. The bottom surface 7, the sides 11a and 11b, and the ends 11c and 11d of the slab 10 come together to form a chamfer 15,
Referring to
Embodiments of the invention include a connector 12 that may comprise a transverse slippable connecting dowel. The dowel may also be referred to as a fastener, connector, key, peg, pin, bar, pole, pipe, conduit, rebar or rod. The connectors 12 may comprise reinforcing steel, such as stainless steel. Each connector 12 may be of standard dimensions, approximately 14-18 inches in length and 1.25-1.5 inches in diameter. The structural capacity of the connector 12 is such that it is sufficient to sustain vertical stresses and loads applied thereto from thermal curling of the pavement slabs and vehicle traffic on the slab 10 and existing pavement 50. In other words, the structural capacity of the connector 12 is sufficient enough to prevent slab 10 and existing pavement 50 from displacing vertically relative to each other in response to the stresses and loads applied thereto. The slippable connectors 12 are mounted truly parallel to the longitudinal axis L of the slab 10 or existing pavement 50 to allow adjacent slabs 10 to expand and contract without inducing unwanted damaging tensile stresses in the slabs 10. The connectors 12 are preferentially mounted such that approximately half of the connector 12 is embedded within the existing pavement 50 and half of the connector 12 extends from the end of the pavement 50 in which the connector 12 is embedded, as depicted in
As depicted in
However, before the insertion of the slab 10 between the vertical edges of the existing roadway 50, selected portions of the roadway 50 must have been cut and removed to reveal the ground there below. A saw, such as a concrete cutting saw may be used to cut vertically down into the existing roadway 50. The existing roadway 50 is cut to dimensions slightly larger than the dimensions of the slab 10 that is to be placed in the existing roadway 50. Thereafter the roadway material within the cut section of the roadway is removed. Once removed, the ground below the removed portion of the roadway 50 can then be dug up to reveal the damaged utility that needs to be repaired. Repairs are performed on the utility and the repaired sections are backfilled. The subgrade 26 is prepared over the backfilled section. The slab 10 may thereafter be vertically placed between the cut vertical edges of the roadway 50.
To install the slab 10, the connectors 12 may first need to be installed/embedded along the edge of the existing roadway 50 to match interconnection slots 14 in the slab 10. If so, a hole may be drilled within the existing roadway 50, using carbide tipped drill bits, or other similar tools. Thereafter, the connector 12 may be inserted within each hole, along with a binder material 17, such as an epoxy resin, a cement-based or epoxy grout, a polymer foam, etc., as depicted in
The binder material 17 used to bind the connector 12 within the drilled hole in the roadway 50 may be, for example, an epoxy resin, such as Anchor Bond 700 or Anchor Fast #221 from Superior Industries, Inc, or the Sikadur® line of epoxy products from Sika Corporation. However, the binder material may be any commercial epoxy resin that has physical properties and characteristics that allow the binder material to be moldable enough to completely fill the annular space between the drilled hole and the slippable dowel thereby fully encasing the dowel such that it cannot move vertically in the existing pavement 50 when vertical loads are imposed on top surfaces of existing pavement 50 and slabs 10. By virtue of the bond breaker film, applied to the connector 12 prior to insertion of the connector 12, the connector 12 may be removed from existing pavement 50 or slabs 10 without damaging the connector 12 or the pavement 50 or slabs 10. In other words, when mechanical force is exerted to remove the connector 12 from the roadway 50 or from slabs 10, as will be described in greater detail below, the binder material remains in place as an integral part of existing pavement 50 or slabs 10 while the connector 12 is removed.
Each interconnection slot 14 may be sized to accommodate the connectors 12 extending from the roadway 50 or positioned on the support 15 on the subgrade 26. Once the connectors 12 are accommodated within the slot 14, the slot 14 is filled around the connectors 12 with a binder material 28, such as grout 28,
With reference again to
In an alternative configuration, the interconnection slot 14 may run through the entire thickness T of the slab 10, such that the interconnection slot 14 may be open to not only the bottom surface of the slab 10 but also the top surface thereof, as depicted in
The slab 10 is placed within the replacement area such that the bottom surface 7 (surface 7 is not labeled in any of the figures) of the slab 10 contacts the subgrade 26 uniformly so as not to disrupt the subgrade 26 or damage the slab 10. During placement, the slab 10 is lowered substantially vertically to the exact location required to match the existing roadway 50, or adjacent slabs 10. Care is taken to insure the interconnection slots 14 are lowered over the connectors 12 extending from the ends and sides of the adjacent roadway 50 or placed on the supports 15 on the subgrade. In particular, as depicted in
In addition, instead of preformed slabs 10, a new pavement may be poured over a framework of connectors 12 placed upon supports 15 that have been placed at predetermined intervals along the subgrade 26. In this way, the new pavement may encompass the connectors 12 and the connectors 12 may be positioned at regular intervals in the new pavement. Thereafter, a preliminary cut may be made in the new pavement over the connectors 12 to a depth not to cut the connectors 12, so as to establish a seam along which the new concrete may crack, if needed. Yet, having the connectors 12 below the seam provides sufficient support to transfer an applied shear load, i.e., from traffic, slab curling or settling, evenly across the seam. Then, in the future, should portions of the roadway, i.e., new pavement, need repair, a deeper cut may be made along the chosen seam to cut the connectors 12 to allow removal of the damaged portion of the roadway, as described herein, to allow removal of the connectors 12, as described herein, and to allow the removed roadway to be replaced by one or more prefabricated slabs 10, as described herein.
After these slabs 10 have been placed in the roadway 50 according to the description above, it may become necessary to remove these slabs 10 for repair of utilities underneath them. Under the condition that one or more of these installed slabs 10 must be removed for any number of reasons, such as, but not limited to, repair or replacement of the utility in the ground below the slab 10, the connectors 12 between the slab 10 and the roadway 50, or between adjacent slabs 10, must necessarily be cut by a cutting device, such as a concrete cutter or other similar sawing device, to free the slab 10. Once freed, the slab 10 can be vertically removed, by a crane, excavator, or other vertical lifting device, from its position in the roadway 50 without having to damage, such as by cutting and/or removal, neighboring roadway, slabs, concrete, pavement, etc.
After vertical removal of the slab 10, a replacement slab 10 may then be placed in the vacancy where the slab 10 once was. The replacement slab 10 may be an identically new slab 10 or the very same slab 10 that was just removed from the roadway 50 to conduct the repairs, the replacement of which will be discussed in greater detail below. Regardless of whether a new slab 10 or the very same slab 10 is repositioned in the roadway 50, it is necessary to install new, full-size connectors 12 in the existing roadway 50 surrounding the vacancy, such that the new connectors 12 can reside partially in the roadway 50 and partially within the interconnection slots 14 of the replacement slab 10.
As depicted in
As depicted in
Also, a captive nut may be used which is also known as an insert nut. Captive nuts are threaded inserts with a knurled base that digs into the end of the connector 12a.
Another example of the engagement component 30 would be an externally threaded insert. Externally threaded inserts have threads on the outside and inside of the insert. The insert is threaded into a pre-tapped hole, or some inserts tap their own threads in a drilled or molded hole. It is then anchored by various means. A thin walled solid bushing insert by the trademarked name Time-sert® is locked in by rolling the bottom few internal thread into the base material with a special install driver which will permanently lock the insert in place.
Another example of the engagement component 30 would be a helical insert. Helical inserts, more commonly known by the trademark Heli-coil®, are inserts made of coiled wire. The insert is inserted into a tapped hole that is larger than the desired hole. They are usually over-sized so that they anchor themselves.
Another example of the engagement component would be a press fit insert. Press fit inserts are internally threaded and have a knurled outer diameter. They are pressed into a plain hole with an arbor press.
Embodiments of the connector 12a may further include a plurality of engagement components 30 that are welded, or otherwise fixedly secured, such as by press fit, compression fit, or friction fit, within the opening 13, wherein each of the engagement components 30 is fixed at a distance from a corresponding distal end of the connector 12a. Embodiments of the connector 12a further include the engagement component 30 being fixedly secured directly to each distal end of the connector 12a.
Embodiments of the connector 12a include the engagement component 30 being secured, or otherwise coupled, to the connector 12a before insertion of the connector 12a in the existing pavement 50 or in the pre-fabricated slab 10. Embodiments of the connector 12a include the engagement component 30 being secured, or otherwise coupled, to the connector 12a after the connector 12a has been cut and remains inside the existing pavement 50 or in the pre-fabricated slab 10. Under conditions that the engagement component 30 is secured, or otherwise coupled, to the connector 12a before insertion of the connector 12a in the existing pavement 50 or in the pre-fabricated slab 10, securing the engagement component 30 within the axial opening 13 at a distance from the end of the connector 12a may prevent concrete, grout, or foam from entering the axial opening 13 and contaminating the engagement component 30, such as the threads of the component, during the embedding of the connector 12a in the existing pavement 50 or in a pre-fabricated slab 10. Moreover, embodiments of the connector 12a include a cap 31 that may be releasably coupled to the connector 12a to prevent ingress of contaminants within the axial opening 13. The cap 31 may be attached to the interior surface, the edge surface, or the outer surface of the connector 12a, or any combination of such, so long as the cap 31 can releasably detach from the connector 12a upon the application of mechanical force.
Embodiments of the invention include the connector 12a being coated with a coating, or bond breaker, which may be placed on the connector 12a prior to insertion within the existing pavement 50. A bond breaker is necessary to prevent the physical bond between the connector 12a and the pavement 50 without reducing the functional interaction between the connector 12a and the pavement 50. In other words, the bond breaker is not thick enough and does not have deterrent properties that would diminish the physical connection between the pavement 50 and the connector 12a. The connector 12a must fit securely and snugly within the pavement 50 so that the connector 12a can adequately transfer and sustain vertical shear loads, such as from vehicle traffic and thermal curling that act on the pavement 50 and that act between the slab 10 and the existing roadway 50. If the connector 12a is not snugly fit or secured within the pavement 50, the connectors 12a will not perform their designed function adequately. The bond breaker also allows the connector 12a to axially displace within the pavement 50 due to thermal expansion. However, as mentioned above, the bond breaker does not diminish the functional interaction between the connector 12a and pavement 50. The bond breaker may be an oil, petroleum or paraffin-based product, such as, but not limited to, Form Oil, such as is known in the art. The bond-breaker may also include paraffin-based products, spray oils, lite-oils, petroleum grease, or the like. The bond breaker may be applied to the connector 12a to assist the removal of the connector 12a, at a later time, should the connector 12a need to be removed, as will be discussed below. Examples of Form Oil include, but are not limited to, Mag 1 from Northern Tool+Equipment or CON-REL-EZE from Petro-Canada.
As depicted in
Once the connectors 12a are inserted in the existing roadway 50, a pre-fabricated slab 10 may be placed over the connectors 12a in the roadway 50, the slots 14 are filled with a binder material 28 such that it structurally connects the pre-fabricated slab 10 with the existing roadway 50, as depicted in
With reference to
Hereinafter, a description of the process of removing a pre-fabricated slab 10, which has been previously installed according to the description above, will be described. As depicted in
Further in reference to
With regard to the solid connector 12, embodiments of the connector 12 include the connector 12 having a shallow bore, or hole, drilled therein, after the connector 12 has been cut in half, such that the gripping means described above may grip and adhere to the shallow bore and provide that the gripping means may thereafter axially advance the connector 12 out of the roadway 50 without damaging or altering the structural integrity of the slab or roadway. The bond breaker, described above, that was previously applied to the connector 12 may facilitate in the removal of the connector 12 from the roadway 50. Boring the solid connector 12 to create a hole is laborious and removal of connector 12 by inserting conventional bolt extractor means in the bored hole is unreliable and time consuming. Thus, a hollow opening 13, such as that pre-configured in connector 12a is advantageous to the removal of the connector 12a.
Embodiments of the connector 12a include the connector 12a being removed by an engagement mechanism 34 that may be inserted into the axial opening 13 until the engagement mechanism 34 engages the engagement component 30 or the engagement surface. The engagement component 34 may be any device that corresponds to and is configured to releasably attach to the engagement component 30 or engagement surface within, or on, the connector 12a. For example, the engagement mechanism 34 may be a loop fixedly coupled within the opening 13 that may be engaged by the engagement component 30, which may be a hook. Further in example, the engagement mechanism 34 may be a spring-loaded anchor that expands when permitted, whereas the engagement component 30 may be a surface, such as a stepped ridge within the opening 13, i.e., the opening 13 having a smaller initial diameter and a larger trailing diameter, with the stepped ridge defined by the sudden change between diameters. Once the spring-loaded anchor is passed by the stepped ridge into the larger diameter, the anchor expands and is prevented from retreating out of the opening 13, thus securing the anchor within the opening 13. After which, the engagement mechanism 34 may be operated to apply axial force to the connector 12a to remove the connector 12a from the opening 13. The bond breaker previously applied to the connector 12a during installation may assist in the removal of the connector 12a.
In embodiments of the connector 12a, engaging the engagement component 30 or engagement surface comprises removably coupling the engagement mechanism 34 to the engagement component 30 or to the engagement surface, such that axial force may be applied to the connector 12a to remove the connector 12a from the slab 10 or roadway 50. In embodiments of the connector 12a, by operating the engagement mechanism 34, the engagement mechanism 34 may releasably engage the engagement component 30 or engagement surface, to thereby apply axial force to the connector 12a to remove the connector 12a from the existing slab 50. Embodiments of the connector 12a may include the engagement mechanism 34 being, for example, a threaded bolt that corresponds to the threads in engagement component 30 or on the internal surface of the opening 13, such that rotational force applied to the engagement mechanism 34 provides axial force to the internal surface of the opening 13, through the engagement of the corresponding threads on both the engagement mechanism 34 and the opening 13. Embodiments of the connector 12a may include the engagement mechanism 34 being, for example, a long coil-thread bolt that corresponds to the threads of the engagement component 30, such that rotational force applied to the engagement mechanism 34 provides axial force to the engagement component 30 through the engagement of the corresponding threads on both the engagement mechanism 34 and the engagement component 30.
As depicted in
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Once the binder material 28 has been removed from the interconnection slots 14 and from the accompanying ports 16, the removed, and now clean, slab 10 may be reinstalled in the roadway 50 from which it was taken. In other words, the removed slab 10 may be placed back in the portion of the roadway 50 from which it was removed. As described above and with reference again to
As depicted in
If after the adjacent slabs 10 are set in place, it becomes necessary to remove one or more of the adjacent slabs 10, a cut is made along the seam, or joint 32, created between the adjacent slabs 10 when assembled, to free the slab 10 from the adjacent slabs 10. As depicted in
The above-described configuration provides for the quick and easy installation and replacement of the pre-fabricated slabs 10, by way of the efficient replacement of connectors 12a, which significantly reduces the time to completion of the repair, while at the same time reducing the labor expense.
While this disclosure has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the present disclosure as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the present disclosure, as required by the following claims. The claims provide the scope of the coverage of the present disclosure and should not be limited to the specific examples provided herein.
This application claims priority to U.S. Provisional Patent Application to Smith entitled “PRE-FABRICATED PAVEMENT SLAB, PAVEMENT SLAB SYSTEM, AND METHOD OF INSTALLING AND REMOVING SAME,” Ser. No. 61/557,393, filed Nov. 8, 2011, the disclosure of which is hereby incorporated entirely herein by reference.
Number | Date | Country | |
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61557393 | Nov 2011 | US |