Patent Abstract:
A structure comprising at least one concrete tile having a bottom major surface, side edges, and a top major surface. A unitary body of concrete is cured about the concrete tile and supports a bottom major surface of the concrete tile. The unitary body is also cured about at least some of the side edges of the at least one concrete tile.

Full Description:
RELATED APPLICATIONS  
       [0001]     This application is a divisional of application Ser. No. 11/353,271, filed Feb. 13, 2006; which is a divisional of U.S. application Ser. No. 10/810,015 filed on Mar. 26, 2004, now U.S. Pat. No. 7,000,361, issued Feb. 21, 2006. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to concrete paving.  
         [0003]     The technology for providing concrete paving that has surface features has become an important field of endeavor with the advent of Americans with Disabilities Act (ADA) current guidelines requirement for detectable warnings on walking surfaces. These detectable warnings must be a grid of raised truncated domes with a diameter of 23 mm (0.9 in) at the base and 10 mm (0.4 in) at the top, a height of 5 mm (0.2 in) and a center-to-center spacing between nearest neighbors of 60 mm (2.35 in).  
         [0004]     A number of different technologies have evolved to create the detectable warnings. First there is a polymer molded product that is about 5 mm (0.1875 in) thick and is provided in the form of tiles having flanges that extend downwardly by 3.5 cm (1.375 in). To install this product, the flanges are pressed into wet concrete. This material is light, and therefore easy to bring to the worksite. It may form a strong bond with the concrete that it is applied onto. Moreover, the fact that it is applied onto wet concrete is a great advantage, as it can be applied at the same time as the concrete is poured, unlike some other methods that are described below. The general term for this type of product is a “wet set” plastic tile.  
         [0005]     A number of other surface feature-bearing elements exist, including: precast concrete blocks, on the order of 5 cm (2 in) thick, brick pavers, glue down plastic elements, glue down rubber mat and hot applied mat. Unfortunately, for each one of these options, the installer must first pour a concrete substrate, wait 28 days for the concrete to thoroughly set, and then return to apply the surface-feature bearing elements. This has been heretofore necessary for any product that had a thickness of more than a few millimeters, as the surface-feature bearing element would otherwise protrude upwardly above the surrounding surface. Precast concrete blocks have had the particular problem that they are so heavy that if set into wet concrete such a block would press down so heavily as to push the wet concrete up around the sides of the concrete block. Any glue down product must be adhered to a finished substrate in order to gain a strong adhesion. Moreover, brick pavers must be laid on an even finished surface. Because they are supported by a substrate that is already solid at the time of installation, all of these products tend to have substantially planar bottom surfaces.  
         [0006]     In a separate sequence of developments, prestressed concrete has been available for many years, with improvements gradually being made to the production process and the resultant product. A relatively recent advancement is described in U.S. Patent Application Publication 2002/0059768 (“the application”), which is incorporated by reference as if fully set forth herein. The application describes a method for producing a thin, lightweight prestressed concrete panel by balancing the tendons about a center plane of the panel. There appears to be no suggestion in the application that the panels thereby produced could be beneficially used as paving tiles.  
         [0007]     Moreover, at first assessment, it would seem to many of those familiar with the technology of concrete installations that the use of this type of panel for paving would be limited to applications in which a substrate of cured concrete first must be provided. This appears to be how the previously available concrete blocks and all of the adhered paving elements have been installed. Moreover, the added expense of using prestressed concrete for applications in which there is not a structural requirement to do so, would not appear practical.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention may take the form of a structure that includes at least one concrete tile having a bottom major surface, side edges, and a top major surface. A unitary body of concrete is cured about the concrete tile and supports a bottom major surface of the concrete tile. The unitary body is also cured about at least some of the side edges of the at least one concrete tile.  
         [0009]     The foregoing and other objectives, features and advantages of the invention will be more readily understood upon consideration of the following detailed description of the preferred embodiment(s), taken in conjunction with the accompanying drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of a shovel guide tool according to a preferred embodiment of the present invention.  
         [0011]      FIG. 2  is a side of the shovel guide tool of  FIG. 1  being positioned above an expanse of formable material, according to a step of a preferred method of the present invention.  
         [0012]      FIG. 3  is a side view of the elements shown in  FIG. 2  with the shovel guide tool pressed into the formable material, according to a further step of a preferred method of the present invention.  
         [0013]      FIG. 4  is a side view of the elements of  FIG. 3 , also showing a shovel being moved along the shovel guide tool, according to a further step of the preferred method of the present invention.  
         [0014]      FIG. 5  is a side view of a finished concrete installation, which may be a result of the method partially shown in  FIGS. 2, 3  and  4  and is in itself a preferred embodiment of the present invention.  
         [0015]      FIG. 6  is a greatly enlarged partial side view of the finished concrete installation of  FIG. 5 .  
         [0016]      FIG. 7  is a partial side view of the finished concrete installation of  FIG. 5 , which is enlarged relative to  FIG. 5 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     A first preferred method of the present invention is a method of removing a predetermined area and depth of wet concrete ( FIG. 2 ), or other formable material, from an expanse of the wet concrete  10 . This is most typically done for the purpose of setting a tile of matching area and thickness (see below). This method makes use of a shovel guide tool  12 , comprising a set of shovel guides  14 , in the form of ribs. A depth and area indicator  16 , is in the form of a rectangular frame having handles  17 . Indicator  16  has a bottom surface that is at a height  18  ( FIG. 2 ) above the tops of shovel guides  14  that is substantially equal to the predetermined depth. The shovel guide tool  12  is pushed into the wet concrete  10  until the bottom surface of the depth indicator  16  is level with the top surface of the wet concrete  10 , thereby pushing the top surface of the shovel guides  14  to the predetermined depth.  
         [0018]     A shovel  20  ( FIG. 4 ) is pushed into the wet concrete until it encounters the top surfaces of the shovel guides  14  and is run along these top surfaces until it is at least partially filled with wet concrete  10 . The shovel  20  is emptied at a location away from the shovel guide tool  12 . The shoveling process is continued until the area indicated by the area indicator  16  is cleared of wet concrete  10  down to the top surfaces of the shovel guides  14 .  
         [0019]     At this point a depression of predetermined depth and area has been created in the wet concrete. In a preferred embodiment guide tool  12  is constructed to create a depression of exactly the right area and depth to accommodate a concrete tile  30  ( FIG. 5 ). Tile  30  may have a width of about 0.6 meters (approximately 2 feet) and may be either about 0.6, 0.75 or 0.9 meters (approximately 2, 2.5, or 3 feet) long. In a preferred method a 3 mm (⅛ in) coat of mortar is applied to the bottom of tile  30  immediately prior to installation. Tile  30  is then placed into the depression created and concrete  10  is compacted and finished about it. Additional wet concrete  10  may be added to help retain a set of wedge sections  32  ( FIG. 4 ) of tile  30 .  
         [0020]     The above described process creates a structure in which tile  30  is supported from the bottom and contacted on the sides by wet concrete  10 . After concrete  10  has cured, this structure is set, with tile  30  being similarly supported and contacted by cured concrete. In a preferred embodiment, tile  30  defines pores  34  ( FIG. 6 ), some of which are at least partially filled with concrete  10 . Also, the bottom surface of tile  30  is indented with a set of furrows  36  ( FIG. 7 ) that facilitate the formation of an interlocked bond with the underlying concrete  10 . The structure created, in which tile  30  is supported and held in place by surrounding concrete  10  is of particular strength. Moreover, it is very resilient to compression and shear, as may be encountered by a concrete installation when trucks either pass by the installation or pass at least partially over the installation.  
         [0021]     Tile  30  may have surface features, such as a grid of truncated domes  40  ( FIG. 4 ). As noted in the background section, domes  40  serve as detectable warnings, and are mandated by the ADA guidelines for various installations including: curb cuts, train station platforms, hazardous vehicular crossings and reflecting pool edges. In some instances a grid having a width of 0.9 meter (@ 3 ft) is required, instead of the standard 0.6 meters (@ 2 ft). Under the current guidelines, domes  40  must have a diameter of 23 mm (0.9 in) at the bottom and 10 mm (0.4 in) at the top, a height of 5 mm (0.2 in) and a center-to-center spacing of 60 mm (2.35 in) between nearest neighbors. Tiles, similar to tile  30 , may be used for other purposes. Among these are adding strength to a concrete paved area; adding a colorful design to an area; adding artistic surface protrusions; and having a set of surface features or a surface shape that facilitates water drainage.  
         [0022]     In one preferred embodiment, tile  30  is of a make generally described in U.S. Patent Application Publication 2002/0059768, which has been incorporated by reference. In an alternative preferred embodiment a concrete paving tile of a differing construction is used. In one preferred embodiment a set of tendons are added that place the bottom half of paving tile  30  under more compressive stress than the top half. As paving tile  30  is supported by concrete material  10 , this unequal compressive stress is, in some instances, beneficial.  
         [0023]     In many types of installations it is beneficial to have a thicker layer of concrete material underneath and supporting tile  30  than elsewhere. In a curb cut installation, wet concrete  10  is formed to a sloping grade prior to the installation of tile  10 , rather than being level.  
         [0024]     In a preferred embodiment, tiles  30  are cast in 0.6 m (2 ft) by 2.4 m (8 ft) by 2.22 cm (0.875 in) sections and are cut in the shop into 0.6 m by 0.6 m, 0.75 m or 0.9 m (2 ft, 2.5 ft or 3 ft) sections. In addition, because tiles  30  are substantially uniform in cross section they may be cut at the job site to accommodate local features. For example, a vault box or a bollard may be accommodated by cutting the tile  30  into an accommodating shape. This task may be difficult or impossible if using tiles that cannot be modified from the standard, factory provided shapes. Such tiles appear to include the wet set plastic tiles and the concrete blocks described in the background section.  
         [0025]     The terms and expressions that have been employed in the foregoing specification are used as terms of description and not of limitation. In particular, the term concrete, wherever it is used in this application, refers to any cementitious material generally used in construction, for example a mixture of cement and sand, commonly known as “mortar” is considered to be “concrete” in this application. There is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.

Technology Classification (CPC): 8