Abstract:
Systems and methods directed to a precast pervious concrete panel. Each pervious concrete panel has a plurality of layers of concrete mixture, wherein the aggregate used in each layer may be a different size. The panels have slots at predetermined locations allowing installation of a joint connector; either dry or with a bonding material thereby allowing connection of multiple panels into a solid slab. Multiple pervious concrete panels can be combined with a collection system allowing collection/reuse of water passing through the panels. Precast pervious concrete panels can be used as inserts in ready mix or cast in place concrete frames allowing for easy replacement of the pieces.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of pending U.S. Divisional patent application Ser. No. 14/296,776, filed 5 Jun. 2014, which claims the benefit of pending U.S. patent application Ser. No. 13/915,954, filed 12 Jun. 2013, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/658,625, filed 12 Jun. 2012; U.S. Provisional Patent Application Ser. No. 61/659,726, filed 14 Jun. 2012; and U.S. Provisional Patent Application Ser. No. 61/761,564, filed 6 Feb. 2013, all entitled, “Precast Pervious Concrete Panels.” 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Pervious concrete is a type of concrete that is highly porous to allow water, for example from precipitation, to pass through the concrete. The use of pervious concrete will reduce runoff from a site and route the runoff into the earth or into a collection system. As such, the use of pervious concrete is consistent with ecologically sustainable construction practices. Pervious concrete may be used for parking lots, sidewalks, driveways, and roadways, as a few non-limiting examples. 
         [0003]    The porous nature of pervious concrete is achieved by the materials that are put into the concrete. Specifically, pervious concrete is a mix of course aggregate, cement, water, chemicals and little to no sand. This mixture creates an open-cell structure in the concrete, which allows water to filter though the pervious concrete. 
         [0004]    Pervious concrete has historically been used in a “ready mix” fashion, delivered to a jobsite and poured into an on-site form. Pervious concrete is unique in many ways including the long cure time to reach maximum strength; the cure time required to reach full strength is typically 28 days or longer. The pervious concrete material must be covered to reduce moisture loss and temperature controlled during the cure time. During this cure time the product does not provide maximum protection and is prone to dilution from water, cracking from stressing or reduced ultimate strength due to temperature. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention relates to pervious concrete, and more particularly to precast pervious concrete panels. The panels comprise elements such as at least one lifting member or pocket to promote easier lifting for transporting the panel and at least one aperture for insertion of a connector used to join panels together. 
         [0006]    Furthermore, the present invention may be used in association with non-pervious surfacing material as part of a drainage system. 
         [0007]    It is further contemplated by the present invention that various ratios of sand and various aggregate sizes may be used for applications requiring different strength characteristics. 
         [0008]    One aspect of the present invention provides a preformed pervious concrete panel comprising a top surface; a first pervious concrete layer comprised of a first aggregate having a first maximum aggregate diameter and extending for a first depth downward from the top surface; a second pervious concrete layer comprised of a second aggregate having a second maximum aggregate diameter and extending for a second depth downward from the first aggregate layer; and the first maximum aggregate diameter is different than the second maximum aggregate diameter. 
         [0009]    Another aspect according to the present invention is to have the first aggregate maximum diameter in the range of about one-quarter inch, three-eighth inch, one-half inch, or three-quarter inch. 
         [0010]    Yet another aspect of the present invention is to have the second maximum aggregate diameter in the range of about one-quarter inch, three-eighth inch, one-half inch, or three-quarter inch. 
         [0011]    A further aspect of the proposed preformed pervious concrete panel is to provide the first maximum aggregate diameter in the range of about one-quarter inch and the second maximum aggregate diameter in the range of about three-eighth inch. 
         [0012]    The preformed pervious concrete panel may also have the first maximum aggregate diameter in the range of about three-eighth inch and the second maximum aggregate diameter in the range of about one-half inch. 
         [0013]    Another aspect of the present invention provides a preformed pervious concrete with a top surface; a first pervious concrete layer, a second pervious concrete layer, and a third pervious concrete layer; the first pervious concrete layer comprising a first aggregate having a first maximum aggregate diameter and extending for a first depth downward from the top surface; the second pervious concrete layer comprising a second aggregate having a second maximum aggregate diameter and extending for a second depth downward from the first pervious concrete layer; the third pervious concrete layer comprising a third aggregate having a third maximum aggregate diameter and extending for a third depth downward from the second pervious concrete layer; and the first maximum aggregate diameter, the second maximum aggregate diameter, and the third maximum aggregate diameter are different from each other. 
         [0014]    Another aspect of the present invention is to provide the first maximum aggregate diameter in the range of about one-quarter inch, three-eighth inch, one-half inch, or three-quarter inch. 
         [0015]    A further aspect of the invention is to provide the second maximum aggregate diameter in the range of about one-quarter inch, three-eighth inch, one-half inch, or three-quarter inch. 
         [0016]    Yet another aspect of the invention is to provide the third maximum aggregate diameter in the range of about one-quarter inch, three-eighth inch, one-half inch, or three-quarter inch. 
         [0017]    The first maximum aggregate diameter may be in the range of about one-quarter inch, the second maximum aggregate diameter may be in the range of about three-eighth inch, and the third maximum aggregate diameter may be in the range of about one-half inch. 
         [0018]    Further, the first maximum aggregate diameter may be in the range of about three-eighth inch, the second maximum aggregate diameter may be in the range of about one-half inch, and the third maximum aggregate diameter may be in the range of about three-quarter inch. 
         [0019]    Yet another aspect of the present invention is to provide a method for producing a pervious concrete panel having a plurality of pervious concrete layers, the method comprising the steps of providing a first concrete mixture comprising a first aggregate having a first maximum aggregate diameter; providing a second concrete mixture comprising a second aggregate having a second maximum aggregate diameter; wherein the first maximum aggregate diameter is different than the second maximum aggregate diameter; laying the second concrete mixture to a second depth; and laying the first concrete mixture on top of the second concrete mixture to a first depth. 
         [0020]    The method may further comprise the steps of providing a third concrete mixture comprising a third aggregate having a third maximum aggregate diameter; wherein the third maximum aggregate diameter is different than the first and second maximum aggregate diameters; and laying the third concrete mixture to a third depth prior to laying the second concrete mixture, whereby the second concrete mixture is laid on top of the third concrete mixture. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a perspective view of a precast pervious concrete panel being formed in a containment vessel. 
           [0022]      FIG. 2  is a perspective view of a precast pervious concrete panel according to the present invention. 
           [0023]      FIG. 3  is a perspective view of two precast pervious concrete panels of  FIG. 2  being joined in according to the present invention. 
           [0024]      FIG. 4  is a perspective view of an insert which may be used with the present invention. 
           [0025]      FIG. 5  is a perspective view of the insert of  FIG. 4  incorporated in a precast pervious concrete panel according to the present invention. 
           [0026]      FIG. 6  is a side view of a water collection system incorporating three of the precast pervious concrete panels of  FIG. 2 . 
           [0027]      FIG. 7  is a top plan view of a concrete system incorporating conventional concrete and one or more of the precast pervious concrete panels of  FIG. 2 . 
           [0028]      FIG. 8  is a cross sectional view of a portion of the system of  FIG. 7 . 
           [0029]      FIG. 9  is a side perspective view of a precast pervious concrete panel having a hollow core according to the present invention. 
           [0030]      FIG. 10  is an exploded perspective view of a system incorporating two of the precast pervious concrete panel of the present invention and a connector member connecting the panels. 
           [0031]      FIG. 11  is an alternative arrangement of a hollow core according to the present invention. 
           [0032]      FIG. 12  is an alternative connector member for connecting the panels. 
           [0033]      FIG. 13  is an exploded perspective view of a system incorporating two of the precast pervious concrete panel of the present invention and the connector of  FIG. 12  connecting the panels. 
           [0034]      FIG. 14  is a segmented cross-sectional view of the pervious concrete panel of  FIG. 2  along line  14 - 14 . 
           [0035]      FIG. 15  is an alternative embodiment of the segmented cross-sectional view shown in  FIG. 14 . 
           [0036]      FIG. 16  is an alternative embodiment of the segmented cross-sectional view shown in  FIG. 14 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0037]    Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. 
         [0038]      FIG. 1  shows a precast pervious concrete panel  10  being formed in a containment vessel  20 . In this manner, the precast pervious concrete panel  10  can be formed and cured in a controlled environment in lieu of pouring wet cast concrete at a jobsite with uncontrolled environment. It should be understood that while a square containment vessel  20  is shown, the containment vessel  20  and thus the panel  10  may be formed in any shape desired, including, but not limited to, square, rectangular, circular, or elliptical forms. In this manner, the invention allows the pervious concrete to be made into standard sizes or shapes and produced in a controlled environment thereby ensuring better quality, strength and consistency. 
         [0039]    The precast pervious concrete panels  10  are preferably sized and configured to be connected to one another. The precast pervious concrete panels  10  may be connected using any methods known in the art. One such method is shown in  FIGS. 2 and 3 .  FIG. 2  shows an embodiment of a precast pervious concrete panel  10  according to the present invention. The precast pervious concrete panel  10  has a first surface  11  and a second surface  13  (see  FIG. 14 ), whereby the depth from the first surface  11  through the second surface  13  defines a panel height H. The height H is preferably approximately 6 inches. 
         [0040]    The panel  10  preferably includes one or more slots  18  cut into the panel  10  at predetermined locations along one or more sides of the panel  10 . The slots  18  are preferably sized and configured to accept a connecting member  22 .  FIG. 3  shows a pair of precast pervious concrete panels  10  being connected to one another. As shown in  FIG. 3 , it should be understood that two adjacent precast pervious concrete panels  10  should each have corresponding slots  18  to accept a connecting member  22 . The number of slots  18  and connecting members  22  may be as few or as numerous as desired. 
         [0041]    The connecting member  22  may take any form known in the art and may be made of any material known in the art. In the illustrated embodiment of  FIG. 3 , the connecting member  22  has a generally oval shape and is made of Korlath. The joint between the precast pervious concrete panels  10  may be dry fitted or a bonding material, such as epoxy, may be used to secure the adjacent precast pervious concrete panels  10 . If used, the bonding material may be used along the entire joint or only at the locations of the slots  18  and connecting members  22 . 
         [0042]    A panel of strip material  24  may be provided under one or more joints between adjacent precast pervious concrete panels  10 . The use of the strip material  24  under the joints will reduce stress concentration at the joint connection by dissipating the load bearing, ensure debris is not pinched between panels  10 , and allow the panels  10  to slide easily together. If used, the strip material  24  may take any form known in the art and may be made of any material known in the art. In the illustrated embodiment the strip material  24  is generally rectangular and is made of Korlath. 
         [0043]    As shown in  FIG. 2 , each precast pervious concrete panels  10  may also include one or more lifting members  26 . In the embodiment shown in  FIG. 2  the lifting members  26  take the form of steel cable loops. However, the lifting members  26  may take any form known in the art, and may be attached to the precast pervious concrete panel  10  using any means known in the art. 
         [0044]    For example, as shown in  FIGS. 4 and 5 , it is contemplated that the lifting members  26  may take the form of one or more receptacles embedded in the precast pervious concrete panel  10 . The receptacle may take any form known in the art including, but not limited to a female connector  28  sized and configured to have a male member (not shown) threaded into the female connector  28 . The male member may take any form known in the art and may be used to lift the precast pervious concrete panel  10 . Although any number of such lifting members may be utilized, it is contemplated that in one embodiment four female connectors  28  would be embedded in each precast pervious concrete panel  10 . The precast pervious concrete panel  10  could then be lifted by a male member threaded into the female connector  28 . 
         [0045]    As shown in  FIG. 6 , one or multiple precast pervious concrete panels  10  can be combined in a collection system allowing collection/reuse of water passing through the precast pervious concrete panels  10 . In such a system a means of collecting water, such as a cistern  30 , is placed beneath the precast pervious concrete panels  10 . The cistern  30  may be placed directly underneath the panels  10  or may be separated from the panels  10  by a drainage material  34  such as gravel as shown in  FIG. 6 . As shown in  FIG. 6 , if desired, the collection system may include a pump  32  to take water from the cistern  30  to distribute the collected water to a desired location. 
         [0046]    It is further contemplated that the precast pervious concrete panels  10  may be formed using any means known in the art. For example, and not by way of limitation, the precast pervious concrete panels could be formed on a slip-forming or extruder machine. This would produce a precast pervious concrete panel  10  with multiple hollow channels  12  running through the panel  10  as shown in  FIG. 9 . This would reduce weight of the panels and material consumption by approximately 20-40%. 
         [0047]    It is further contemplated that precast pervious concrete panels  10  may be used as inserts to be used in combination with traditional concrete or asphalt as shown in  FIG. 7 . It is further contemplated that traditional concrete or asphalt may be used as inserts to be used in combination with precast pervious concrete panels  10 , in  FIG. 7 . In this manner, conventional concrete  40  could be cast in place, leaving space to insert the precast pervious concrete panels  10 . Preferably, conventional concrete  40  would be cast with a ledge  42  so that the precast pervious concrete inserts  10  could sit on the ledge  42  as shown in  FIG. 8 . This would reduce costs as compared to using pervious concrete alone, and would increase drainage as opposed to using only conventional concrete. The precast pervious concrete panels  10  could be placed in a decorative pattern or arrangement if desired. To that end, if desired, the precast pervious concrete panels  10  could be integrally colored. 
         [0048]    It is further contemplated that the precast pervious concrete panels  10  could be reinforced using any means known in the art including, but not limited to, embedding rebar, fibers or mesh in the precast pervious concrete panels  10 . 
         [0049]    It is further contemplated that the precast pervious concrete panels  10  may be connected in a manner as shown in  FIG. 10 , with further reference to  FIG. 13  illustrating various aperture and connector shapes. It is contemplated that a first precast pervious concrete panel  10  having at least one first aperture  12  could be connected to a second precast pervious concrete panel  10  having at least one second aperture (hidden). The first and second apertures may be formed in the first and second panel using any means known in the art. For example, and not by way of limitation, the first and/or second apertures could be a hollow core extending through the first and/or second panels respectively. It is further contemplated that the first and/or second apertures could be formed in the first and/or second panels. It is contemplated that a connector  50  having a first end  52  sized and configured to fit within and engage the first aperture  12  and a second end  54  sized and configured to fit within and engage the second aperture (hidden) may be utilized to connect the first and second panels  10 . It is further contemplated that the connector may include a hard stop  56  such that the first end  52  of the connector  50  will slide into the core of the first panel  10  until it reaches the hard stop  56 , the second end  54  of the connector  50  will slide into the core of the second panel  10  until it reaches the hard stop  56 . The hard stop  56  will preferably create a gap between the first and second panels. Furthermore, the size of the panel will determine the number of connectors  50 , where there could be as few as one or as many as there are apertures in each panel. Additionally, a panel may incorporate apertures of a variety of different shapes or combinations of different shapes. As a non-limiting example,  FIG. 11  further illustrates a panel  10  having oval apertures  14  along with circular apertures  16 . 
         [0050]    The profile of the connectors  50  may substantially match the cores of the panels  10 ; they may be round or any other shape used to make the panel&#39;s core. For example, the connector  50  in  FIG. 10  has a “teardrop” shape and the connector  50  in  FIGS. 12 and 13  has a rectangular shape. The connectors  50  can be hollow or solid and are preferably made of a non-corrosive material, including but not limited to plastic or metal. 
         [0051]    As outlined above, pervious concrete is a mix of course aggregate, cement, water, and little to no sand. It is further contemplated that the precast pervious concrete panels  10  may be cast using any combination of such materials known in the art. However, it is contemplated that the pervious concrete mixture may be designed to meet the specified strength and permeability of the intended application. Typically, the stronger the precast pervious concrete panel  10 , the more material required which reduces the permeability, therefore each application may have a unique mix. The mixes will be classified based off their aggregate size and their sand content. Preferably the pervious concrete material will have a range of aggregate typically varying from about ⅛-¾″ in diameter and sand content ratios up to 10%. For example, a mix for a sidewalk or patio according to the present invention may utilize an aggregate with a diameter in the range of about ⅛″-⅜″ and include up to approximately 7% sand content. This mixture would provide a minimum strength of 3,500 psi, an 18-22% void ratio, and infiltration rates exceeding 500 inches/hour. Alternatively, a mix for a highway shoulder or parking stall may employ an aggregate with a diameter in the range of about 5/16″-½″ and up to approximately 7% sand content. This mixture would provide a minimum strength of 4,000 psi, a 16-20% void ratio, and infiltration rates exceeding 500 inches/hour. 
         [0052]    It is further contemplated that it may be desirable to provide a pervious concrete panel including multiple layers, such that the aggregate size for each layer may be independently selectable from the aggregate size in the other layers in the pervious concrete panel. 
         [0053]      FIGS. 14-16  illustrate various aggregate layering embodiments according to the present invention. For the following discussion, the first surface  11  is also referred to as the top surface and the second surface  13  is also referred to as the bottom surface. It should be understood that the various diameters of aggregate disclosed herein are preferable diameters, but the invention should not be construed as being limited to only those diameters. 
         [0054]      FIG. 14  illustrates a first embodiment  100  of a cross-section of the pervious concrete panel  10  along the line  14 - 14  of  FIG. 2 . The cross-section is comprised of a concrete mixture  116  with a similarly dimensioned aggregate  112  throughout the entire height H of the pervious concrete panel  10 . The aggregate  112  is preferably comprised of aggregate selected from a group having aggregate with a maximum aggregate diameter  114  substantially in the range of about ¼″, ⅜″, ½″, or ¾″. 
         [0055]      FIG. 15  illustrates a second embodiment  200  of the cross-section of the pervious concrete panel  10  along the line  14 - 14  of  FIG. 2 . The cross-section is comprised of a first pervious concrete layer  210  having a first concrete mixture  216  with a first aggregate  212  with a first maximum aggregate diameter  214  and extending downward from the top surface  11  for a first depth A, and a second pervious concrete layer  220  comprised of a second concrete mixture  226  having a second aggregate  222  with a second maximum aggregate diameter  224  and extending downward for a second depth B from the first pervious concrete layer  210 , whereby the sum of the first depth A and the second depth B equals the height H. 
         [0056]    In one embodiment, the first depth A is approximately 1 inch and the second depth B is approximately 5 inches. The first and second maximum aggregate diameters  214 , 224  are different and are preferably selected from aggregate having a maximum aggregate diameter of substantially about ¼″, ⅜″, ½″, or ¾″. In the embodiment shown in  FIG. 15 , the second maximum aggregate diameter  224  is greater than the first maximum aggregate diameter  214 , however, the reverse is contemplated. 
         [0057]      FIG. 16  illustrates a third embodiment  300  of a cross-section of the pervious concrete panel  10  along the line  16 - 16  of  FIG. 2 . The cross-section is comprised of a first pervious concrete layer  310  comprised of a first concrete mixture  316  having a first aggregate  312  with a first maximum aggregate diameter  314  and extending downward from a top surface  11  for a first depth A, a second pervious concrete layer  320  comprised of a second concrete mixture  326  having a second aggregate  322  with a second maximum aggregate diameter  324  and extending downward for a second depth B from the first pervious concrete layer  310 , and a third pervious concrete layer  330  comprised of a third concrete mixture  336  having a third aggregate  332  with a third maximum aggregate diameter  334  and extending downward for a third depth C from the second pervious concrete layer  320 . 
         [0058]    In one embodiment, the first depth A is approximately 1 inch, the second depth B is approximately inches, and the third depth C is approximately 2 inches. The first, second, and third maximum aggregate diameters  314 , 324 , 334  are different from each other and are preferably selected from a group having a maximum aggregate diameter of substantially about ¼″, ⅜″, ½″, or ¾″. In the embodiment shown in  FIG. 16 , the third maximum aggregate diameter  334  is greater than the second maximum aggregate diameter  324 , and the second maximum aggregate diameter  324  is greater than the first maximum aggregate diameter  314 ; however, other combinations of pervious concrete layers, each comprising an aggregate mixture having a maximum aggregate diameter different than the maximum aggregate diameters of the aggregate in the other layers, are contemplated. 
         [0059]    A method for producing a pervious concrete panel  10  having a plurality of pervious concrete layers each comprised of aggregate of a different maximum diameter is contemplated. For example, a method to produce the third embodiment  300  of a pervious concrete panel as provided in  FIG. 16  preferably comprises the steps as follows. The first concrete mixture  316 , the second concrete mixture  326 , and the third concrete mixture  336  are provided. 
         [0060]    The third concrete mixture  336  is laid along a surface and compacted to the third depth C, thus forming the third pervious concrete layer  330 . The second concrete mixture  326  is laid onto the third pervious concrete layer  330  prior to the third concrete mixture  336  fully curing. The second concrete mixture  326  is compacted to the second depth B and forms the second pervious concrete layer  326 . The first concrete mixture  316  is laid onto the second pervious concrete layer  320  before the second concrete mixture  326  is fully cured. The first concrete mixture  316  is compacted to the first depth A and forms the first pervious concrete layer  316 . 
         [0061]    The method may further comprise the step of troweling the first concrete mixture  316  to provide a smooth finish on the first layer  310 . 
         [0062]    Additionally or alternatively, the different concrete mixtures  316 , 326 , 336  may be laid in different orders to form multi-layered concrete panels of various characteristics. 
         [0063]    It is contemplated that the second and third concrete layers  326 , 336  may be comprised of the same concrete mixture, thus forming the two layer concrete panel  200  with the first pervious concrete layer  216  and the second pervious concrete layer  226  as shown in  FIG. 15 . 
         [0064]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.