Abstract:
A precast pervious concrete panel is formed in a containment vessel under controlled conditions and allowed to reach an acceptable strength before removal from the containment vessel, thereby producing standard sizes or shapes for installation in the field. Each piece of pervious concrete may include slots cut into the piece at predetermined locations allowing installation of a joint connector; either dry or with a bonding material thereby allowing connection of multiple pieces into a solid slab. A strip material may be used under the slab joints to dissipate load bearing and allow the panels to slide together when picked up by the embedded lifting device. Multiple pervious concrete pieces 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 divisional 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. 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 or “add material,” 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 is typically 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; due to the makeup of pervious concrete, the cure time required to reach full strength is typically 28 days or longer. The pervious concrete material must be covered and controlled during the cure time. During thus 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 invention provides a preformed pervious concrete panel including a concrete mix having an aggregate size in the range of about one-eighth inch to about three-quarters inch and a sand content ratio in the range of zero percent to ten percent, a peripheral surface, a least one lifting member at least partially integrated into the peripheral surface, and at least one aperture located in the peripheral surface. 
         [0009]    The aggregate size may also be in the range of about one-eighth inch to about one-half inch. 
         [0010]    The sand content ratio may also be in the range of 1 percent to 7 percent. 
         [0011]    The sand content ratio may also be zero percent. 
         [0012]    The pervious concrete panel may also include a void ratio in the range of 16 percent to 22 percent. 
         [0013]    The void ratio may also be in the range of 18 percent to 22 percent. 
         [0014]    The at least one ting member may also be a female connector. 
         [0015]    The at least one lifting member may also be a steel cable loop. 
         [0016]    The at least one aperture may extend continuously linearly through the panel. 
         [0017]    Another aspect of the invention provides a pervious concrete system including at least a first and a second preformed pervious concrete panels, each of the preformed pervious concrete panels including a concrete mix having an aggregate size in the range of about one-eighth inch to about three-quarters inch and a sand content ratio in the range of zero percent to ten percent, a peripheral surface, at least one lifting member at least partially integrated into the peripheral surface, and at least one aperture located in the peripheral surface; at least one connector having a first and a second oppositely disposed ends; and wherein the first end of the connector is received in an aperture of a first panel and the second end of the connector is received in an aperture of the second panel, thereby joining the first and second panels. 
         [0018]    The pervious concrete system may also include a piece of strip material placed underneath the panels at the joint. 
         [0019]    The at least one connector may have a hard-stop to provide a gap between the panels. 
         [0020]    Another aspect of the invention provides a method for producing a pervious concrete panel including providing a pervious concrete mix having a an aggregate size in the range of about one-eighth inch to about three-quarters inch and a sand content ratio in the range of zero percent to ten percent, providing a containment vessel having a shape defining the peripheral surface of the panel, providing at least one lifting member, introducing the pervious concrete mix into the containment vessel, forming at least one aperture in the peripheral surface, arranging the lifting member in the mix at a predetermined location in the peripheral surface prior to the mix fully curing, allowing the pervious concrete mix to cure for a predetermined amount of time, and separating the panel from the containment vessel. 
         [0021]    The aggregate size may also be in the range of about one-eighth inch to about one-half inch. 
         [0022]    The sand content ratio may also be in the range of 1 percent to 7 percent. 
         [0023]    The sand content ratio may also be zero percent. 
         [0024]    The method for producing a pervious concrete panel may also include a pervious concrete panel with a void ratio in the range of 16 percent to 22 percent. 
         [0025]    The void ratio may also be in the range of 18 percent to 22 percent. 
         [0026]    Another aspect of the invention provides a method for producing a pervious concrete panel including providing a pervious concrete mix having a an aggregate size in the range of about one-eighth inch to about three-quarters inch and a sand content ratio in the range of zero percent to 10 percent, providing at least one lifting member, forming the panel having a peripheral surface with a continuously moving form, forming at least one aperture in the peripheral surface, arranging the lifting member in the mix at a predetermined location in the peripheral surface prior to the mix fully curing. 
         [0027]    The method for producing a pervious concrete panel may include forming the panel with a slip-forming machine. 
         [0028]    The method for producing a pervious concrete panel may include forming the panel with an extruding machine. 
         [0029]    The aggregate size may also be in the range of about one-eight inch to about one-half inch. 
         [0030]    The sand content ratio may also be in the range of 1 percent to 7 percent. 
         [0031]    The sand content ratio may also be zero percent. 
         [0032]    The method for producing a pervious concrete panel may also include a pervious concrete panel with a void ratio in the range of 16 percent to 22 percent. 
         [0033]    The void ratio may also be in the range of 18 percent to 22 percent. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]      FIG. 1  is a perspective view of a precast pervious concrete panel being formed in a containment vessel. 
           [0035]      FIG. 2  is a perspective view of a precast pervious concrete panel according to the present invention. 
           [0036]      FIG. 3  is a perspective view of two precast pervious concrete panels of  FIG. 2  being joined in according to the present invention. 
           [0037]      FIG. 4  is a perspective view of an insert which may be used with the present invention. 
           [0038]      FIG. 5  is a perspective view of the insert of  FIG. 4  incorporated in a precast pervious concrete panel according to the present invention. 
           [0039]      FIG. 6  is a side view of a water collection system incorporating three of the precast pervious concrete panels of  FIG. 2 . 
           [0040]      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 . 
           [0041]      FIG. 8  is a cross sectional view of a portion of the system of  FIG. 7 . 
           [0042]      FIG. 9  is a side perspective view of a precast pervious concrete panel having a hollow core according to the present invention. 
           [0043]      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. 
           [0044]      FIG. 11  is an alternative arrangement of a hollow core according to the present invention. 
           [0045]      FIG. 12  is an alternative connector member for connecting the panels. 
           [0046]      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. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0047]    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. 
         [0048]      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. 
         [0049]    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  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 previous 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. 
         [0050]    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 . 
         [0051]    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. 
         [0052]    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. 
         [0053]    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 . 
         [0054]    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. 
         [0055]    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 running through the panel  10  as shown in  FIG. 9 . This would reduce weight of the panels and material consumption by approximately 20-40%. 
         [0056]    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 . 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. 
         [0057]    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 . 
         [0058]    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 . 
         [0059]    The profile of the connectors  50  may substantially match the cores of the panes  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. 
         [0060]    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 aggregates typically varying from about ⅛-¾″ in size 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 size 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 size 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. 
         [0061]    A method for producing a pervious concrete panel  10  comprises: providing a pervious concrete mix having a predetermined aggregate size and percentage of sand; providing a means for forming the pervious concrete panel; providing a means for lifting the pervious concrete panel; introducing the pervious concrete mix into the forming means; incorporating the lifting means; and curing the pervious concrete mix. 
         [0062]    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.