Patent Application
20140369750
1. Field of the Invention
This invention relates to a moisture (i.e., water) impermeable grout containment sheet and to a method including the step of locating the sheet within an excavation so as to lie between a (e.g., concrete) panel that has been lowered into the excavation and grout that has been pumped below the panel. The group containment sheet and method have particular application during roadway construction or repair where a plurality of concrete panels are laid in excavations formed in a road bed and connected to one another to support vehicular traffic.
2. Background Art
As new communities are built, it is essential to have a roadway system to link each community with neighboring communities. Therefore, a series of highways and freeways are constructed to support vehicular traffic. A common technique for building such roadways is to lay a number of heavy concrete panels or slabs end-to-end and side-by-side one another. All of the panels must be held in place relative to one another and connected together to establish a smooth and continuous driving surface. The foregoing is often accomplished by first grading a road bed and cutting excavations therein within which the concrete panels are laid.
Once the concrete panels are located within the excavations, grout is typically pumped below the panels to retain the panels above the road bed. However, with the heavy panels sitting on top, the grout has been known to migrate underneath adjacent panels located within a single excavation or within adjacent excavations. Such migration can adversely affect the stability and level of the concrete panel relative to other panels. Moreover, the water with which the grout is mixed can sometimes seep into and be absorbed by the road bed below the panel. What is even more, the grout lying below the panel within the excavation is susceptible to the negative effects of being exposed to too much water. Such additional water may originate as rain water and/or ground water from the road bed. Until it is completely cured and hardened, which could take up to seven days or more, grout which becomes either too dry or too wet may become brittle or weakened and lose its maximum structural integrity and load-bearing ability.
Therefore, what would be desirable is a means to prevent the grout that is pumped between a concrete and and the road bed upon which the panel is laid from migrating away from the panel as well as losing its moisture and becoming too wet throughout the road construction project.
Briefly, and in general terms, a grout containment sheet and method are disclosed having particular application, for example, during roadway construction or repair when excavations are cut into a road bed and (e.g., precast concrete) panels are laid inside the excavations to be connected end-to-end and/or side-by-side. Prior to laying a panel within an excavation, a moisture (i.e., water) impermeable (e.g., polyurethane) grout containment sheet is positioned inside the excavation to cover at least the bottom thereof. The grout containment, sheet must be sufficiently strong to prevent water from passing therethrough.
The panel is lowered into the excavation so as to lie upon the grout containment sheet. In order to hold the panel in place within the excavation, grout or a similar adhesive bonding material is pumped below the panel such as, for example, by way of filler tubes which run through the panel. Thus, the grout containment sheet lies between the grout and the road bed above which the panel is located. By virtue of the foregoing, the grout containment sheet establishes a containment envelope around the grout throughout the construction project to prevent the grout from migrating away from the panel. At the same time, the grout containment sheet creates a barrier that prevents the grout from both drying out as a consequence of the moisture of the grout being absorbed by the road bed and from becoming too wet as a consequence of being exposed to rain water and ground water. Accordingly, the maximum strength, structural integrity and load-bearing characteristics of the grout upon which the panel is laid and supported can be maintained.
Shown and described herein are a water-impermeable grout containment sheet and a method for using the sheet with a solid (e.g., concrete) panel or slab where the panel is transported to and laid upon the sheet after the sheet is first located inside an excavation that is cut into a solid surface. By way of example, the grout containment sheet and method herein disclosed have particular application during roadway construction and/or repair where a plurality of concrete panels are laid inside one or more excavations so as to be connected end-to-end and/or side-by-side one another. In this same regard, the system and method are also advantageous to facilitating the removal of a panel from its excavation should such removal be required during subsequent roadway maintenance and repair.
Turning to the drawings,
In accordance with a preferred embodiment of this invention, a moisture (i.e., water) impermeable grout containment sheet 20 is laid inside the excavation 10 so as to completely cover the bottom thereof. It is important that the grout containment sheet 20 be long enough to initially extend upwardly and over top of the road bed 15 so that the sheet will not be pulled entirely inside the excavation 10 when a heavy panel is laid upon the sheet. The grout containment sheet 20 may be carried to the construction site, for example, on a roll of continuous sheet material which is cut to size. Depending upon the size of the excavation 10, it may be necessary to add one or more additional containment sheets (not shown) which overlap one another in end-to-end alignment. By way of example only, the water-impermeable grout containment sheet 20 has a thickness of at last 6 mils. The sheet 20 which covers the bottom of the excavation 10 must be manufactured from a material (e.g., polyurethane) that is strong enough to support a load (e.g., a concrete panel) located inside the excavation 10 and prevent water from passing through the sheet.
With the grout containment sheet 20 laid inside the excavation 10 and covering the bottom thereof, and referring now to
Accordingly, it may be appreciated that the water-impermeable grout containment sheet 20 lies between the grout 30 and the bottom of the excavation 10 that has been cut into the solid surface (i.e., road bed 15) to receive the (e.g., concrete) panel 25. By virtue of the foregoing, the containment sheet 20 establishes a liner or barrier to prevent the grout bonding material 30 from migrating away from the panel 25 and flowing below an adjacent panel 35. To this end, portions of the sheet 20 are pulled upwardly to create a peripheral fold (designated 22 in
What is even still more, the grout containment shed 20 facilitates a removal of the panel 25 from the excavation 10 for subsequent repair or replacement. By spraying or coating the bottom of the panel 25 at the time of construction with a conventional liquid bond breaker, the panel can be titled out of the excavation 10 so as to be either replaced with a different panel or cleaned, repaired and returned to the excavation. In this case, the grout 30 will adhere to the grout containment sheet 20 so as to permit a relatively easy separation of the panel 25 from the grout 30 which remains inside the excavation.
As previously explained, a plurality of panels, like those designated 25 and 35, which have been lowered into respective excavations or a single continuous excavation, like that designated 10, can be connected, such as by means of dowel bar couplers (designated 40 in
