Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-11-12
2001-11-06
Ball, Michael W. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S091000, C156S293000, C052S745210
Reexamination Certificate
active
06312541
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to repairing concrete and, more particularly, relates to a method and apparatus for joining concrete sections together.
2. Discussion of the Related Art
Over time, cracks can develop within concrete structures which, if left unrepaired, can result in failure of the structure. To prevent such an occurrence without having to replace an entire slab, damaged slabs are often repaired by cutting a damaged section away from a preexisting concrete section, and by pouring new concrete in its place. However, new concrete does not always bond perfectly with the preexisting concrete, and cracks can propagate in the joint between the two sections.
Previous methods have been implemented to repair concrete structures and maintain the mechanical connection between a new concrete section and a preexisting concrete section. One repair method involves first removing defective concrete and drilling holes in the preexisting concrete using a rotary impact hammer drill. An adhesive is then placed into the holes, and reinforcing bars are inserted such that the bars extend beyond the outer wall of the preexisting concrete and are generally perpendicular to the joint between the preexisting concrete section and the gap defining the area where the new concrete is to be poured. The new concrete is then poured adjacent the preexisting concrete such that the ends of the reinforcing bars extend into the new concrete and bond with the new concrete when it cures. Therefore, when the new concrete cures, it will be joined to the preexisting concrete via the reinforcing bars.
Additionally, when attaching external fixtures to preexisting concrete sections, holes are drilled using, e.g., a standard rotary drill, and anchors are either bonded or friction-fitted within the holes. The external fixtures are then mounted onto the anchors.
Several disadvantages are associated with these methods of repair and attachment. For example, drilling multiple holes into the existing concrete is a slow and labor intensive process. Additionally, the vibrations associated with the drilling can cause an entire section of concrete to fail. Moreover, once a hole is drilled, it must be subsequently cleaned of dust and concrete particles in order to permit the adhesive to bond to the concrete. In addition, cracks can form over time in the joint between the new section and the preexisting concrete. As moisture seeps down these cracks, a metallic reinforcing bar will rust, corrode, and subsequently fail, thereby necessitating further repair. Additionally, a phenomenon known in the industry as “burping” may occur, whereby air pockets become trapped within the hole once the reinforcing bar is installed, thereby preventing at least a portion of the adhesive from bonding with the reinforcing bar. This can lead to premature failure of the reinforced joint.
In another type of concrete structure, for example a parking garage structure, a concrete driveway is disposed above T-shaped concrete beams that are typically joined together by metal clips. As cracks form in the concrete, however, moisture seeps into the supports and corrodes the metal clips, ultimately causing them to fail. One previous method of repairing this type of structure involved welding or bolting a supplemental joining apparatus to both supports, thereby retaining them together. This method, however, is expensive and labor intensive. Additionally, the repair is aesthetically unappealing. Another method of repair involved cutting through the concrete to access and replace the failed metal clip. Again, this process is labor intensive and expensive.
The need has therefore arisen to provide an improved method and apparatus for repairing and/or adding external fixtures to concrete structures that retains the integrity of the preexisting concrete, that is not labor intensive, that does not corrode over time, and that resists premature failure.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore a first object of the present invention to provide a method and apparatus for repairing and/or attaching external fixtures to concrete that is not as labor intensive as previous repair systems.
It is a second object of the invention to provide an insert for repairing concrete that will not corrode over time.
It is a third object of the invention to provide an insert of a shape that allows the insert to mate with a slot within a preexisting section of concrete as opposed to a bore and that therefore does not require drilling holes into the existing concrete.
It is a fourth object of the invention to provide an insert that comprises cavities and/or texture to increase its bonding capabilities and resist premature failure.
It is a fifth object of the invention to provide a method and apparatus for repairing concrete while minimizing the risk of damaging the preexisting concrete during the repair process.
It is a sixth object of the invention to provide a method and apparatus for repairing two adjacent preexisting sections of concrete.
In accordance with a first aspect of the invention, the concrete to be replaced is removed by one of many known methods. A slot is then formed in the preexisting concrete, preferably with a diamond blade circular saw, in the surface that is adjacent and faces the area where the new concrete is to be added. Once the slot is created, an adhesive, preferably an epoxy compound, is inserted within it. A generally flat insert is then placed within the slot and is retained in place once the adhesive dries. A substantial part of the insert is exposed and extends from the preexisting concrete such that it will become immersed in newly poured concrete. The insert then bonds with the new concrete as it cures, thereby joining the two sections of concrete together.
In accordance with an alternate embodiment of the invention, the insert may comprise a threaded extension, extending generally perpendicular to the wall of concrete in which the insert is placed, that may be attached to a reinforcing bar or bars of a preexisting section of concrete, thereby joining the two concrete sections together. Alternatively, the insert may be installed into a preexisting concrete section, and the threaded extension may be used to support external fixtures, for example lights, while using the preexisting concrete as an anchor for the external fixtures.
In accordance with a second aspect of the invention, the insert is formed from a composite material such that moisture seeping into the joint between the new concrete and preexisting concrete will not corrode the insert.
In accordance with a third aspect of the invention, the insert may be a generally flat elongated object with an arcuate outer edge that is preferably configured to mate with the slot in the preexisting concrete. The generally flat insert also presents a relatively large exposed surface area to increase bonding with the adhesive and new concrete.
In accordance with a fourth aspect of the invention, the insert may have a textured exterior to help lock the insert in place when the adhesive and new concrete dry. Additionally, internal cavities may be created within the insert to permit the epoxy (on one end) and concrete (on the other end) to flow and cure within the cavities, thereby further strengthening the insert's retention in the concrete structure. The cavities also function to permit air to escape when the insert is set into the slot in the concrete to permit maximum bonding between the adhesive and the insert and to minimize the risk of premature failure.
In accordance with a fifth aspect of the invention, the slot within the preexisting concrete may be created with a circular diamond saw blade. As a result, dust and particles that are created during the cutting process are automatically ejected by the rotating diamond blade. The lack of significant vibration reduces the risk of damaging the existing concrete while creating the slot.
In accordance with a sixth aspect of the invention, an insert is usable to join two preexisting sections
Ball Michael W.
Nilles & Nilles S.C.
Piazza Gladys
LandOfFree
Method and apparatus for repairing concrete does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for repairing concrete, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for repairing concrete will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2617612