Abstract:
Systems and methods for a porous pavement system are described. The porous pavement system includes paver blocks designed to facilitate water seepage between the paver blocks and to permit water storage within the blocks. The paver blocks may be cabled together to create paving units that facilitate installation and maintenance of the pavement system. The porous pavement system provides improved management of stormwater, reducing runoff and facilitating infiltration of stormwater into the subgrade below the paving system.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates in general to the field of paving systems. More particularly, the present invention relates to paver blocks. Specifically, a preferred embodiment of the present invention relates to paver blocks which may be installed individually or as paving units and which provide fluid storage within the paver blocks. 
         [0003]    2. Discussion of the Related Art 
         [0004]    As is known to those skilled in the art, paving systems historically create a surface impervious to rain. The water that falls on the paved surface runs off the edge of the paving surface rather than being absorbed into the ground beneath the paved surface. It is recognized that an increasing number of paved surfaces and the subsequent stormwater runoff from these paved surfaces contributes to lowered water tables and rising stream levels. Thus, it is a previously recognized problem with paving systems that stormwater runoff needs to be managed. 
         [0005]    Historically, it was known in the prior art to manage stormwater using a curb and gutter system to guide the stormwater into sewer systems. More recently the stormwater has been guided into detention basins to allow the water to be absorbed closer to the paved surface. Needless to say, it is desirable to provide a porous pavement system allowing the stormwater to drain through the paving system and to be absorbed into the ground under the paving system, minimizing the need for any additional stormwater management system. 
         [0006]    However, such a porous pavement system has not been fully met without incurring various disadvantages. For example, U.S. Pat. No. 5,797,698 and U.S. Pat. No. 6,939,077 disclose paving elements designed to allow water to drain between adjacent paving blocks. While these paver blocks, as disclosed, allow stormwater to drain down the sides of the block, they are still susceptible to one of the major drawbacks of existing porous pavement systems: they are totally dependent on the aggregate subgrade and the underlying soil for infiltration. Sandy or rocky soils have more cracks and fissures that allow the water to filter into and away from the surface, but heavy, clay soils do not drain quickly and require a longer retention time prior to the water entering the soil. 
         [0007]    Another unsatisfactory, previously recognized approach to solving the problem of being dependent on the subgrade and soil for infiltration involves the use of underground storage systems. These storage systems are made of plastic and have several feet of aggregate dumped on top of them. A disadvantage of this approach is the inability to clean out the underground storage systems once they are filled with sedimentation and particulates from stormwater runoff. Therefore, a preferred solution will manage the stormwater runoff to improve infiltration of the water into any type of soil and, if it becomes necessary, will allow for sedimentation to be cleaned out from the water storage system. 
       SUMMARY AND OBJECTS OF THE INVENTION 
       [0008]    Consistent with the foregoing and in accordance with the invention as embodied and broadly described herein, a paver block and a porous pavement system are disclosed in suitable detail to enable one of ordinary skill in the art to make and use the invention. 
         [0009]    In one embodiment of the invention, a paver block includes an upper surface and a lower surface opposite the upper surface. The upper and lower surfaces are connected by a plurality of sides. At least one of the sides includes a drainage spacer that extends along at least a portion of the side. At least one of the lower surface and the plurality of sides has a cavity at least partially enclosed by the paver block. The cavity allows fluid to be stored within the paver block, and the volume of the cavity is at least two percent of the volume of the paver block. 
         [0010]    In another embodiment of the invention, the cavity extends along the lower surface of the paver block. The width of the cavity is between 25 and 50 percent of the width of the lower surface, and the height of the cavity is between 25 and 50 percent of the height of one of the sides of the paver block. 
         [0011]    In still another embodiment, the cavity extends along one of the sides of the paver block. The height of the cavity is between 25 and 50 percent of the height of one of the sides, and the width of the cavity is between 20 and 50 percent of the width of the upper surface of the paver block. 
         [0012]    In another embodiment, the upper surface joins the plurality of sides at a rounded edge, and the angle, alpha, between at least one of the sides and a vertical plane is less than about three degrees. In yet another embodiment, the cavity of the paver block is arched, and in still another embodiment, the cavity of the paver block has sufficient volume to store at least an inch of rain that falls on the upper surface of the block. 
         [0013]    In one embodiment, the paver block includes an upper surface and a lower surface opposite the upper surface. The upper and lower surfaces are connected by a plurality of sides. At least one of the sides includes a drainage spacer that extends along at least a portion of the side. A first side of the paver block contains at least one aperture and a second, opposing side contains at least one aperture. Each of the apertures on the first side has a corresponding aperture on the second side and a fluid passage is defined between each of the corresponding apertures. The volume of the at least one fluid passage is at least two percent of the volume of the paver block and allows fluid storage within the paver block. 
         [0014]    In still another embodiment of the invention, a porous pavement system includes a plurality of paver blocks. Each of the plurality of blocks may be, but is not limited to, one of the embodiments of paver blocks described above. A cable runs through a plurality of ducts. Each duct is contained within one of the plurality of blocks. The cable-connected blocks may then be installed as a single paving unit. 
         [0015]    These and other aspects and objects of the present invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the present invention, is given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    A clear conception of the advantages and features constituting the present invention, and of the construction and operation of typical mechanisms provided with the present invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting, embodiments illustrated in the drawings accompanying and forming a part of this specification, wherein like reference numerals designate the same elements in the several views, and in which: 
           [0017]      FIG. 1  is a top view of a first embodiment of a paver block; 
           [0018]      FIG. 2  is a sectional view taken along  2 - 2  of  FIG. 1 ; 
           [0019]      FIG. 3  is an end view of a first embodiment of a paver block; 
           [0020]      FIG. 4  is a side view of a first embodiment of a paver block; 
           [0021]      FIG. 5  is an end view of a second embodiment of a paver block; 
           [0022]      FIG. 6  is a top view of a first embodiment of a paving unit; 
           [0023]      FIG. 7  is a sectional view taken along  7 - 7  of  FIG. 6 ; 
           [0024]      FIG. 8  is a top view of a first embodiment of a porous paving system; 
           [0025]      FIG. 9  is a bottom view of a grout joint connecting two paving units; 
           [0026]      FIG. 10  is a sectional view taken along  10 - 10  of  FIG. 9 ; and 
           [0027]      FIG. 11  is an exemplary embodiment of lifting a paving unit. 
       
    
    
       [0028]    In describing the preferred embodiments of the invention which are illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word “connected”, “attached”, or terms similar thereto are often used. They are not limited to direct connection but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art. 
       DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0029]    The present invention and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments described in detail in the following description. 
       1. System Overview 
       [0030]    In basic form, the invention is a porous paving system made up of paver blocks. These blocks may be installed individually or, alternately, cabling may be passed through ducts in the blocks and multiple paver blocks may be installed in a single unit. The paver blocks are designed to facilitate water drainage down the sides of the block. In addition, the paver blocks include a cavity allowing for the storage of fluid within the paver block. This results in a porous paving system that provides for stormwater storage within the paving system unlike conventional paving systems. 
       2. Detailed Description of Preferred Embodiments 
       [0031]    Specific embodiments of the present invention will now be further described by the following, non-limiting examples which will serve to illustrate various features of significance. The examples are intended merely to facilitate an understanding of ways in which the present invention may be practiced and to further enable those of skill in the art to practice the present invention. Accordingly, the examples should not be construed as limiting the scope of the present invention. 
         [0032]    Turning initially to  FIGS. 1-4 , a preferred embodiment of a paver block  20  used in a porous paving system  100  is depicted. The paver block  20  is generally comprised of an upper surface  25 , a lower surface  30 , a plurality of sides  35 , and a cavity  40 . It is contemplated that the paver block  20  could be of any shape known to one of ordinary skill in the art, including, but not limited to, a square, a rectangle, and a hexagon. A preferred embodiment is illustrated in  FIG. 1  where the paver block  20  has two flat sides  35   a, b  and two stepped sides  35   c, d . Additionally, the paver block  20 , may be manufactured in a variety of heights, H 1 , widths, W 1 , and depths, D 1 , with a preferred minimum block size being at least 12 inches wide, 12 inches deep, and 5 inches high. The paver block may be manufactured out of any material known to one of ordinary skill in the art, but is preferably a concrete block. At least one drainage spacer  45  extends at least partially along one of the sides  35   a - d  of the paver block  20 . In the preferred embodiment, two drainage spacers  45  extend vertically along the entire height, H 1 , of one of the sides  35   a - d  of the paver block  20 . In addition, at least one, and preferably all, of edges  50  between the upper surface  25  and each of the sides  35   a - d  will be rounded, creating seepage down the sides of the block. 
         [0033]    A cavity  40  allows fluid storage within the paver block  20 , and is especially designed to contain stormwater that has drained down the sides of the paver block  20 . The cavity  40  may be partially or wholly defined by the paver block  20 . The cavity  40  may be designed in a wide variety of shapes and sizes to allow for fluid storage within the paver block  20 . In a preferred embodiment of the cavity  40 , illustrated in  FIG. 3 , the cavity  40  is an arch extending along the entire bottom surface  30 . Another embodiment of the cavity  40  is shown in  FIG. 5  wherein the cavity  40  is a fluid passage  65  extending entirely through the paver block  20 . A further embodiment of the cavity  40 , not illustrated, may include multiple fluid passages  65  extending through the paver block  20 . Still another embodiment of the cavity  40 , not illustrated, may be an arch extending along the side  35   a - d  of the paver block. The aforementioned examples disclose several embodiments for the cavity  40 , but the structure of the cavity  40  could be any shape or size capable of storing fluid within the block such as, but not limited to, a square or rectangular cavity extending across the bottom, side or through the paver block  20 . 
         [0034]    The paver block  20  is designed to balance fluid storage and structural integrity. Preferably, the volume of the cavity  40  allows for at least the first inch of stormwater that falls on the top surface  25  of the paver block  20  to be stored within the cavity  40  of the paver block  20 . This stored water subsequently filters out of the cavity  40  into the aggregate subgrade  135  and soil below the paving system  100 . 
         [0035]    The paver blocks  20  may be installed individually to create a porous paved surface. Alternately, multiple blocks may be installed as a single paving unit  115  to increase speed and efficiency of installation of the porous pavement system  100 . To permit installation as a single paving unit  115 , each paver block  20  includes holes or ducts  110  passing through the paver block  20 . Each duct  110  is sized to allow a cable  105  to pass therethrough, and is preferably one inch in diameter. In addition, the sides  35   a - d  of the blocks through which the ducts  110  pass will have some angle, alpha, between the side  35   a - d  and a vertical plane. It is desirable to minimize this angle as much as possible, but the angle allows some flexibility between blocks in a paving unit  115 . It is desirable to keep this angle, alpha, less than 3 degrees and preferably between 1 and 2 degrees. 
         [0036]    Referencing  FIG. 6 , the paving unit  115  is constructed by passing at least one cable  105  through multiple paver blocks  20 . It is contemplated that the paving unit  115  will be of varying widths, W 3 , and lengths, L, to accommodate the desired application, including, but not limited to, pathways, driveways, parking lots, and roads. Preferably the paving unit  115  is about 8 feet wide and may extend from 8 to 60 feet in length. Based on its application, the paver block may accommodate either pedestrian or vehicular traffic. The paver block  20  is preferably designed to accommodate a load of up to 4000 pounds per square inch. 
         [0037]    Referencing  FIGS. 8 and 9 , multiple paving units may be installed either adjacent to each other or in an end-to-end configuration. When two paving units  115  are installed adjacent to each other, the paver blocks  20  along the side of a paving unit  115  are staggered such that the side blocks of the first paving unit  115  interweave with the side blocks of the second paving unit  115 , creating a continuous paved surface. In addition, the ducts  110  of the paver blocks  20  in the first paving unit  115  align with the ducts  110  of the paver blocks  20  in the second paving unit  115 , allowing an interlocking cable  120  to pass therethrough, securing the first paving unit  115  to the second paving unit  115 . 
         [0038]    When the blocks of two paving units  115  are installed in an end-to-end configuration, a preferred joining method is depicted in  FIG. 9 . The cables  105  of the first paving unit  115  are tucked into the cavities  40  of the paver blocks  20  at the end of the second paving unit  115 . Likewise, the cables  105  of the second paving unit  115  are tucked into the cavities  40  of the paver blocks  20  at the end of the first paving unit  115 . A sheath  125  is laid into the gap between the two paving units  115 , desirably using a very narrow veneer plastic sheath. Preferably, the plastic sheath  125  is only ten to twelve inches wide and eight to ten mils thick. This sheath prevents grout from entering the cavities  40  of the paver blocks  20  at the end of either paving unit  115  and additionally isolates the cables  105  from the grout. Finally, grout is poured between the two paving units  115  to form a joint  130 . The grout may be of any type known to one of skill in the art and suitable for the application, but is preferably a pervious concrete or small aggregate grout. 
         [0039]    Each paving unit is preferably installed as a single unit. Referring to  FIG. 11 , an exemplary paving unit  115  is being lifted using a crane, but installation may be performed by any means known to one skilled in the art, such as a forklift. Further, if cleaning of the cavities  40  of the paver blocks  20  becomes necessary, the paving unit  115  may be subsequently lifted out, the cavities  40  and subgrade  135  cleaned of debris, and the paving unit  115  reinstalled. 
         [0040]    In another embodiment, each duct is about 2.75 inches from the bottom of each block. Each paving unit may extend from about 8 feet to about 60 feet in length. In a further embodiment, the cavities in each of the plurality of blocks has sufficient volume to store at least one inch of rain from the upper surface of the plurality of blocks in the paving unit. The stored rain water then filters into the subgrade under the paving unit. 
         [0041]    In yet another embodiment of the invention, the cable may be, but is not limited to, one of the following materials: polyester, stainless steel, and galvanized steel. The paving unit, after having been installed, may subsequently be lifted as a single unit to allow cleaning of the cavities of each of the paving blocks if necessary. The paving unit may further be reinstalled as one unit once cleaning of the cavities is complete. In still another embodiment, the cavities of each of the paving blocks may be cleaned while the paving unit remains installed. 
         [0042]    In another embodiment, a first paving unit may be installed adjacent to a second paving unit. The blocks along the edges of the first paving unit and the second paving unit interweave. In yet another embodiment, a cable may alternately pass through a duct of the first paving unit and a duct of the second paving unit to interlock the first and the second paving units. 
         [0043]    In a final embodiment, two paving units may be installed such that an end of the first paving unit is positioned next to the end of the second paving unit. A sheath may be used, preferably an 8 to 10 mil thickness plastic, to line the area between the two paving units and prevent grout from entering the cavities on the plurality of blocks. A grout joint may seal the area between the two paving units. The grout joint may consist of, but is not limited to, pervious concrete or small aggregate. 
         [0044]    Although the best mode contemplated by the inventors of carrying out the present invention is disclosed above, practice of the present invention is not limited thereto. It will be manifest that various additions, modifications and rearrangements of the features of the present invention may be made without deviating from the spirit and scope of the underlying inventive concept. 
         [0045]    Moreover, the individual components need not be formed in the disclosed shapes, or assembled in the disclosed configuration, but could be provided in virtually any shape, so as to provide a paver block with a cavity capable of storing fluid. Furthermore, all the disclosed features of each disclosed embodiment can be combined with, or substituted for, the disclosed features of every other disclosed embodiment except where such features are mutually exclusive. 
         [0046]    It is intended that the appended claims cover all such additions, modifications and rearrangements. Expedient embodiments of the present invention are differentiated by the appended claims.