Abstract:
A prefabricated paving slab includes specialized combinations of substantially vertical passages and cavities to enable “drop in” installation. The paving slab may include retractable coupling rods aligned using spacers having seating surfaces and alignment surfaces. Cavities of the paving slab, each configured for receiving a coupling rod, preferably are arranged in orientation(s) and pattern(s) selected for receiving and transferring the stresses of loads travelling in a pre-determined direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the benefit of U.S. Provisional Application Ser. No. 62/275,093, filed Jan. 5, 2016, and entitled BLOW-OUT DOWEL; the entirety of which is hereby incorporated herein by reference, to the extent permitted by law. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field 
         [0003]    The present invention relates to apparatus, systems and methods for preparing and installing modular pavement. The present invention more particularly relates to improved pre-fabricated, modular paving apparatus, systems and methods for preparing and installing same. 
         [0004]    2. Discussion of Related Art 
         [0005]    It is known to join adjacent modular pavement slabs to enable load transfer between the slabs. For example, U.S. Pat. No. 5,586,834 to Tsuji (“Tsuji”) discloses a simple arrangement in which a reinforcing bar (5) is installed by centering it between long and short cavities (4, 9) of respective adjoining slabs. The bar (5) may be centered by pulling a flexible hauling member (13) through a guide passage (11) and horizontal hole (9) in the short cavity slab to move the bar (5) from the long cavity (4). Once the bar (5) is centered between the slabs, the long and short cavities may be grouted by a filler charging device connected via apertures adjacent the ends of the cavities. (Tsuji, FIG. 1 and cols. 3-4) 
         [0006]    Existing systems may, however, lead to haphazard and imprecise assembly, as well as ineffective load transfer. It is desirable to provide apparatus, systems and methods for improved coupling of adjacent modular pavement slabs. 
         [0007]    This background discussion is intended to provide information related to the present invention which is not necessarily prior art. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    Embodiments of the present invention address problems and limitations of the prior art by providing a pavement apparatus and system configured specifically to improve the quality and ease of positioning coupling means. Embodiments of the present invention further provide improved load distribution and design efficiency through configurations—including patterns and locations—of a plurality of coupling means distributed across at least one pavement apparatus. 
         [0009]    According to one aspect of the present invention, a system for coupling a pavement slab to an adjacent receiving structure is provided. The system includes a substantially horizontal first cavity in the slab terminating along a side of the slab. The system also includes a substantially horizontal second cavity in the receiving structure terminating along a side of the receiving structure, the side of the receiving structure being adjacent to the side of the slab in an installed configuration. The system also includes a coupling rod having a first portion received within the first cavity and a second portion received within the second cavity. The system also includes a spacer having a seating surface configured to receive a lower surface of the coupling rod and an alignment surface for positioning in alignment with a landmark segment of the slab. 
         [0010]    A second aspect of the present invention concerns a pavement slab for coupling to a substantially identical adjacent structure. The slab includes opposite first and second faces extending in a first direction, the first direction being parallel to a direction of load progression. The slab also includes opposite third and fourth faces extending in a second direction substantially orthogonal to the first direction. The slab also includes a first plurality of cavities configured to receive coupling rods, each of such cavities having a length defined in the second direction and a diameter defined orthogonally to the second direction, with each of such cavities terminating in one of the first and second faces. The slab also includes a second plurality of cavities configured to receive coupling rods, each such cavity having a length defined in the first direction and a diameter defined orthogonally to the first direction, and each such cavity terminating in one of the third and fourth faces. Preferably, each of the first plurality of cavities is at least as distant from the third and fourth faces in the first direction as the length of a longest cavity of the second plurality of cavities. 
         [0011]    In regard to a third aspect of the present invention, a method for installing adjacent pavement slabs method is provided. The method includes aligning a plurality of cavities spaced along a side of a first slab with a corresponding plurality of cavities spaced along a side of a receiving structure. The method further includes adjusting the position of a plurality of coupling rods, each of the plurality of coupling rods being at least partially within one of the plurality of cavities and at least partially within one of the corresponding plurality of cavities. Preferably, the adjustment of the position of each of the plurality of coupling rods is effected using at least one spacer for each of the plurality of coupling rods. Further, each spacer preferably includes a seating surface configured to receive a lower surface of the coupling rod and an alignment surface for positioning in alignment with a landmark segment of the first slab. 
         [0012]    In regard to a fourth aspect of the present invention, a system is provided for coupling a pavement slab to an adjacent receiving structure. The system includes a substantially horizontal first cavity in the slab terminating along a side of the slab and a substantially horizontal second cavity in the receiving structure terminating along a side of the receiving structure, the side of the receiving structure being positioned adjacent to the side of the slab. The system also includes a coupling rod having a first portion received within the first cavity and a second portion received within the second cavity in an installed, extended configuration. The system also includes a first passage positioned along a lateral axis at least partially above a first end of the coupling rod in the installed, extended configuration. The system also includes a second passage positioned along a lateral axis at least partially above a second end of the coupling rod in the installed, extended configuration. The system further includes a third passage positioned along a lateral axis at least partially above the first end of the coupling rod in an uninstalled, retracted configuration. The first cavity is preferably configured to accommodate substantially the entire length of the coupling rod and the second cavity is configured to accommodate approximately one half of the entire length of the coupling rod. 
         [0013]    This summary is provided to introduce a selection of concepts in a simplified form. These concepts are further described below in the detailed description of the preferred embodiments. 
         [0014]    This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
         [0015]    Various other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0016]    Preferred embodiments of the present invention are described in detail below with reference to the attached drawing figures, wherein: 
           [0017]      FIG. 1  is a top schematic view of a modular pavement system according to an embodiment of the present inventive concept and indicating a direction of anticipated load progression, the system including four slabs each having first and second pluralities of cavities and coupling rods in an, extended installed configuration; 
           [0018]      FIG. 2  is a top schematic view of a slab of  FIG. 1  having a middle segment of a top surface of the slab removed to reveal a portion of an exemplary internal reinforcement grid; 
           [0019]      FIG. 3  is a top view of the slab of  FIG. 2  illustrating a plurality of prestress tendons and indicating a direction of anticipated load progression; 
           [0020]      FIG. 4  is a sectional side view taken through the middle segment of the slab of  FIG. 2  and further illustrating the exemplary internal reinforcement grid and relative positioning of receiver ports; 
           [0021]      FIG. 5  is a side view of the slab of  FIG. 2  illustrating a first face including two groupings of a first plurality of cavities and relative positioning of receiver ports; 
           [0022]      FIG. 6  is a top schematic view of a slab of  FIG. 1  illustrating the first and second pluralities of cavities with intersecting substantially vertical passages; 
           [0023]      FIG. 7  is another side view of the first face of  FIG. 5 , additionally illustrating associated vertical passages of the two groupings of the first plurality of cavities as well as two of the second plurality of cavities (and associated vertical passages); 
           [0024]      FIG. 8  is a side view of the slab of  FIG. 2  illustrating a fourth face including half of the second plurality of cavities (and associated vertical passages) along with relative positioning of receiver ports; 
           [0025]      FIG. 9  is a sectional side view of a long cavity of a slab (and associated vertical passages) and a coupling rod in an uninstalled, retracted configuration; 
           [0026]      FIG. 10  is a sectional side view of a slab including an underlying grout layer, the slab having a long cavity aligned with a corresponding short cavity of an adjacent receiving structure and a coupling rod in an installed, extended configuration; 
           [0027]      FIG. 11  is an elevated perspective view of a slab according to an embodiment of the present inventive concept lying on a truck bed for delivery and having coupling rods partially inserted into male (long) cavities along first and fourth faces of the slab; 
           [0028]      FIG. 12  is an elevated perspective view of the slab of  FIG. 11  with coupling rods fully inserted and with strips of pre-cut joint filler material being prepared for application to the first and fourth faces prior to installation of the slab; 
           [0029]      FIGS. 13-14  are elevated perspective views of the slab of  FIG. 11  in the process of being lifted and re-positioned by a crane from the truck bed via hauling cables connected to lift lugs (not shown) embedded within receiver ports of the slab; 
           [0030]      FIG. 15  is an elevated schematic view of three slabs aligned for installation; 
           [0031]      FIG. 16  is an elevated side sectional view of adjacent substantially identical slabs, the left slab including a male (long) cavity being aligned with a female (short) cavity of the right slab and housing a coupling rod in an uninstalled, retracted configuration, and a passage of the right slab housing a spacer; 
           [0032]      FIG. 17  is an elevated side sectional view of the slabs of  FIG. 16  with the coupling rod having been extended into the female cavity of the right slab using a pipe auger such that a lower surface of the coupling rod rests on a seating surface of the spacer; 
           [0033]      FIG. 18  is an elevated side sectional view of the slabs of  FIG. 17  including an additional spacer housed in a passage of the left slab on which a first end of the coupling rod rests; 
           [0034]      FIG. 19  is an elevated side sectional view of the slabs of  FIG. 18  illustrating the coupling rod being adjusted using the spacers; 
           [0035]      FIG. 20  is an elevated side sectional view of the slabs of  FIG. 19  including a plug inserted into the passage of the left slab; 
           [0036]      FIG. 21  is an elevated side sectional view of the slabs of  FIG. 20  illustrating the grouting of portions of the horizontal cavities and passages of the left and right slabs using a grouting nozzle; 
           [0037]      FIG. 22  is an elevated side sectional view of the slabs of  FIG. 21  after removal of the plug and grouting nozzle; 
           [0038]      FIG. 23  is an elevated schematic view of a slab during addition of an underlying grout layer using a grouting nozzle pumping grout through a receiver port and grouting port (not shown); and 
           [0039]      FIG. 24  is an elevated schematic view of four slabs midway through finishing installation steps, namely illustrating partial completion of patching remaining surface holes (such as upper segments of passages and receiver ports) using the grouting nozzle (not shown). 
       
    
    
       [0040]    The drawing figures do not limit the present invention to the specific embodiments disclosed and described herein. 
         [0041]    The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the preferred embodiments. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0042]    The present invention is susceptible of embodiment in many different forms. While the drawings illustrate, and the specification describes, certain preferred embodiments of the invention, it is to be understood that such disclosure is by way of example only. There is no intent to limit the principles of the present invention to the particular disclosed embodiments. 
         [0043]      FIG. 1  illustrates a system of four pavement slabs  100 , with each such slab  100  being coupled to two neighboring slabs  100 . Each slab  100  includes opposite first and second faces  102 ,  104  extending in a first direction D generally corresponding to a direction of anticipated load progression that, in the illustrated embodiment, is the direction of anticipated travel for vehicles. Each slab  100  also includes opposite third and fourth faces  106 ,  108  extending in a second direction generally perpendicular to the first direction D. 
         [0044]    Each slab  100  has four groupings of cavities belonging to a first plurality of cavities  110 —two groupings along each of the first and second faces  102 ,  104 . In the depicted embodiment, rotating the groupings along the first face  102  one hundred eighty degrees (180°) generates the configuration seen along the second face  104 . The first plurality of cavities  110  alternate between two lengths L 1 , L 2  defined in the second direction and have a uniform diameter defined orthogonally to the second direction. 
         [0045]    Each slab also has a second plurality of cavities  112  along the third and fourth faces  106 ,  108 . The second plurality of cavities  112  are evenly spaced along substantially the entire lengths of the third and fourth faces  106 ,  108 —preferably about twelve inches (12″) center-to-center—and also alternate between two lengths L 1 , L 2 , where such lengths are defined in the first direction D. The diameters of cavities  112  are defined orthogonally to the first direction D. 
         [0046]      FIG. 1  also illustrates coupling rods  114  along the inner faces of slabs  100  in an extended, installed configuration. 
         [0047]    Preferably, cavities having length L 1  (that is long, male cavities) are configured to accommodate at least the entire length of a coupling rod, for example while in an uninstalled, retracted position. Cavities having length L 2  are preferably configured to accommodate at least approximately half the entire length of a coupling rod. Enabling a fully retracted position using cavities of length L 1  enables an installer to drop a slab  100  into place flush against adjacent structures prior to extending coupling rods for engagement and installation. This provides for easier installation, removal and replacement of slabs adjacent surrounding structures, without the requirement of disturbing or moving the surrounding structures. Embodiments including only cavities of shorter length L 2  may lack this advantage. Cavities  110  are evenly spaced from one another within each grouping of four, preferably about twelve inches (12″) center-to-center, with some additional space between groupings and along the edges of the slabs  100 . 
         [0048]    Preferably, cavities  110 ,  112  are cylindrical and have diameters determined according to the following formula: 
         [0000]    
       
         
           
             
               
                 d 
                 cav 
               
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                 ( 
                 inches 
                 ) 
               
             
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                             Distance 
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                             center 
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                           top 
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                           surface 
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                           of 
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                            
                           slab 
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                             ( 
                             inches 
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                 8 
               
             
           
         
       
     
         [0049]    Preferably, the diameters of the coupling rods  114  are determined by taking the value for cavity diameter (d cav ) determined by the above formula and subtracting one inch (1″). 
         [0050]    Preferably, L 1  is determined by the length of the coupling rod plus the internal diameter of a third vertical passage described below, minus an inset depth sufficient to preclude environmental deterioration, typically 2″ or less. Preferably, L 2  is determined according to similar principles. 
         [0051]    It is possible to perform the foregoing and other dimensional calculations in connection with varying embodiments in alternative order(s) according to known mathematical principles, and/or to vary same according to factors and considerations commonly considered in similar design applications, without departing from the spirit of the present inventive concept. 
         [0052]    In the illustrated embodiment, no cavity  110  is closer to a third face  106  or a fourth face  108  than a distance equal to the length of the longest cavity of the second plurality of cavities  112  (in this case L 1 ) and, in fact, each is removed from such faces  106 ,  108  by an even greater distance. It is foreseen that yet more distance may be added to this separation without departing from the spirit of the present inventive concept (i.e., at least about twice the length of the longest cavity of the second plurality of cavities  112 , or two times L 1 ). This separation improves the integrity of the slabs  100  by ensuring there is significant pavement material between adjacent cavities. Moreover, in embodiments where cavities  110 ,  112  are located at approximately the same depth within the slabs  100 , this separation ensures no two cavities will intersect, which could interfere with structural integrity and/or grouting/finishing processes such as those described herein. 
         [0053]    The cavities illustrated in  FIG. 1  alternate between long and short lengths L 1 , L 2 , generally corresponding respectively to male and female functionality in receiving coupling rods  114  between them. It is foreseen that embodiments may alternatively employ a first slab face having cavities exclusively of uniform, male, length and a second, opposite slab face having cavities exclusively of uniform, female, length, without departing from the spirit of the present inventive concept. It is further foreseen that embodiments may alternatively employ a slab face with approximately half of its cavities forming a first grouping of adjacent cavities of uniform, male, length and the remaining cavities forming a second grouping of adjacent cavities of uniform, female, length, without departing from the spirit of the present inventive concept. In the embodiments described in the preceding sentence, the cavities in each grouping are preferably evenly spaced from one another, with the first grouping preferably occupying approximately one half the length of the face and the second grouping occupying approximately the second half of the length of the face. 
         [0054]    In the embodiment illustrated in  FIG. 1 , there are fifty percent (50%) more cavities  112  and corresponding coupling rods  114  than there are cavities  110  with corresponding coupling rods  114 . This design is optimized in this manner to respond to predominant load progression in the first direction D, which places additional stresses on the interfaces between faces  106 ,  108  that are not felt to the same degree at the interfaces between faces  102 ,  104 . However, it is envisioned that other groupings, spacing, cavity lengths and diameters and the like may be utilized without departing from the spirit of the present inventive concept. For example, groupings may also be used for cavities  112 ; for example a grouping may be located below anticipated wheel paths in the case of load progression involving vehicle travel. 
         [0055]    Cavities  110 ,  112  (and also the substantially vertical passages discussed below that are formed integrally with and/or intersect with cavities  110 ,  112 ) may be hollows formed within slabs  100 , or may be fabricated from material(s) suitable to be embedded into and/or bonded to, concrete and other cementitious materials. Where fabricated, such material(s) may be molded and placed into a concrete precast form before the main body of the slab  100  itself is poured or formed around them. Typically, suitable materials include steel (both plain and with various coatings and surface treatments), fiberglass, and carbon fiber. 
         [0056]    The main body of the slabs  100  may be composed of reinforced (or unreinforced) geopolymer, plastic, hollowcore, fiberglass, carbon fiber, foamed concrete, pervious concrete or similar material, or other suitable materials. The slabs  100  may further include an internal reinforcement system such as, for example, a series of alternating layers of steel rebar or fiberglass or carbon fiber reinforcement materials embedded within the concrete. The internal reinforcement system improves the ductility and/or tensile strength of the paving apparatus. For example,  FIG. 2  illustrates an example of an internal reinforcement grid  116  comprising a lattice of epoxy-coated rebar embedded within the slabs  100 . The slabs  100  may further include post tension tendons or strands (see  FIG. 3 ), which may slow the development of cracks along the main body of the slabs  100 . Still further, the upper periphery of the slabs  100  may be shaped to include a chamfer  117 , as generally illustrated in  FIG. 2 . 
         [0057]    Referring more generally to  FIGS. 2-5 , the slabs  100  further include receiver ports  118  having receiver lugs (not shown) embedded therein. The receiver lugs may be secured to the internal reinforcement grid  116  and/or be sufficiently embedded in the main body of the slabs  100  to permit lifting thereby without damaging the integrity of the main body of the slabs  100 . Alternatively, the receiver lugs may include flanges or the like positioned along portions of a bottom  120  of the slab, permitting the force of lifting to be distributed thereacross. The receiver lugs are configured for attachment to a crane or hoist for lifting (see  FIG. 14 ). 
         [0058]    Receiver ports  118  are spaced across a top surface  119  of each slab  100  to enable balanced lifting. As illustrated, for example, a slab  100  having a length (SL) and width (SW) has four receiver ports  118 . Each receiver port  118  is separated from its adjacent corner along a length axis by twenty percent (20%) of the total length of the slab (PL), and likewise is separated from its adjacent corner along a width axis by twenty percent (20%) of the total width of the slab (PW). Receiver ports  118  may further provide fluid communication with a bottom  120  of the slab  100  via a grouting port  122 . The grouting port  122  may include a hollow sheath centered on the lower terminus of the pickup (e.g., a PVC sheath). It is foreseen that the grouting ports  122  may comprise other materials, or may simply be defined by the main body of the slabs  100  themselves, without departing from the spirit of the present inventive concept. 
         [0059]    Exemplary receiver ports useful with embodiments of the present invention are described in United States Patent Publication No. 20150010354A1 to Sylvester, filed Sep. 4, 2014 (the “&#39;354 Publication”), which is hereby incorporated herein by reference in its entirety. Exemplary ports described therein may be referred to as “access ports.” For example, it is foreseen that such receiver ports may provide access to additional components, such as sensors, in accordance with the teachings of the &#39;354 Publication, without departing from the spirit of the present inventive concept. It is still further foreseen that alternative means for moving and securing coupling rods in a lateral direction may be employed with embodiments described herein, again in accordance with the teachings of the &#39;354 Publication, without departing from the spirit of the present inventive concept. 
         [0060]    Turning now to  FIGS. 6-8 , a slab  100  is illustrated in additional detail. Each of cavities  110 ,  112  of length L 1 , i.e., the longer male cavities, intersects with a first substantially vertical passage  124  nearer the edge of the slab  100 . Each of cavities  110 ,  112  of length L 2 , i.e., the shorter female cavities, intersects with a second substantially vertical passage  126  near the edge of the slab  100 . First and second substantially vertical passages  124 ,  126  assist in alignment, including by housing spacer devices (otherwise referred to as “dowel hangers” or “dowel chairs”) described in additional detail below. First and second substantially vertical passages  124 ,  126  may also provide points of ventilation during filler or grouting processes. 
         [0061]    Each of cavities  110 ,  112  of length L 1 , i.e., the male cavities, also intersects with a third vertical passage  128  adjacent its internal terminus. The third vertical passages  128  may assist in the extension of coupling rods  114  from male cavities. In an embodiment, a snake or pipe auger (see  FIG. 17 ) is extended through the third vertical passage  128  to urge the coupling rod  114  in a telescoping movement into the female cavity of an adjacent slab, i.e., a cavity having length L 2 . 
         [0062]    Turning now to  FIGS. 9-10 , a slab  100  is illustrated in additional detail sectioned through a substantially horizontal cavity housing a coupling rod  114 .  FIG. 9  illustrates slab  100  in an uninstalled, retracted configuration with third vertical passage  128  at least partially above an interior first end  130  of coupling rod  114 . In a preferred embodiment, however, the third vertical passage  128  is only minimally above the coupling rod  114 —the coupling rod  114  is instead preferably offset toward the side of the slab  100 , only partly extending across the width of the third vertical passage  128 . A second end  132  of the coupling rod  114  is essentially flush with the outer face of the slab  100  in the uninstalled, retracted configuration. 
         [0063]    Also depicted in  FIGS. 9-10  is a joint filler  134 , which is preferably pre-cut and attached to the outer face of at least one of the slabs  100  prior to placing two slabs  100  next to each other for coupling, as will be described in additional detail below with reference to  FIG. 12 . The joint filler may comprise any material to facilitate joint sealing, force transfer, installation and/or removal of the slabs. Suitable materials include rubber, plastic, or polymer compounds, such as a recycled tire product. These materials preferably form a “compression garment” or “bumper” around the slab. They may be applied in strips as described herein to either or both of two adjacent structures or slabs, preferably prior to installation. The material can extend the full depth of the slab and joint and substantially exclude water by fitting tightly against its neighboring structures. 
         [0064]      FIG. 10  illustrates sections of two slabs  100  having outer faces sitting essentially flush against one another.  FIG. 10  also illustrates a coupling rod  114  extended laterally into an installed position, with first end  130  being at least partially below first vertical passage  124 , and second end  132  being at least partially below second vertical passage  126  and near a stopping surface  133 . While passages  124 ,  126 ,  128  are preferably vertical as illustrated, it is foreseen that they may be oriented other than substantially vertically without departing from the spirit of the present inventive concept. For example, passage  128  may permit access to a pipe auger, and passages  124 ,  126  may permit access to spacer devices, even if oriented other than substantially orthogonal to the substantially horizontal top surfaces  119  of the slabs  100 . 
         [0065]      FIGS. 9-10  illustrate the coupling rod  114  as centered within the male and female cavities, though in practice such centering preferably results, in the present inventive concept, from using spacers substantially according to the description below. The illustrated coupling rod  114  is substantially cylindrical, as are the surrounding/enclosing cavities, and the coupling rod  114  has been adjusted for an optimal pre-determined separation—in this case approximately 12.77 mm or about half an inch (0.5″)—between a lower surface  136  of the coupling rod  114  and a lower inner surface  138  of the cavity. Essentially the same separation is also seen between an upper surface  140  of the coupling rod  114  and an upper inner surface  142  of the cavity, and is preferably also present around substantially the entire perimeter of the coupling rod  114 . 
         [0066]    Turning to  FIGS. 11-24 , a method of installing pavements slabs  100  is described by progressive illustration.  FIG. 11  illustrates a plurality of coupling rods  114  as they are being slid into male cavities  110 ,  112  along faces  102 ,  108  of a slab  100 .  FIG. 12  illustrates applying pre-cut joint filler material  134 —which includes apertures aligned with cavities  110 ,  112  to permit movement of coupling rods  114  therethrough—to faces  102 ,  108 . The foregoing insertion and attachment steps are shown occurring on the bed of a truck, and preferably on a truck that includes a mobile crane, but it is envisioned that such steps may occur in a variety of locations, for example during fabrication and prior to transport to the installation site, without departing from the spirit of the present inventive concept. 
         [0067]      FIGS. 13-14  illustrate attaching a crane to receiver ports  118  and lifting the slab  100  toward at least one receiving structure for alignment therewith and positioning adjacent thereto, preferably on a prepared grade surface.  FIG. 15  illustrates three aligned and adjacent slabs  100  in position for beginning the coupling process. 
         [0068]      FIG. 16  illustrates detail from a cross-sectional view of a coupling rod  114  in retracted, uninstalled position within a male cavity, with first end  130  at least partially below third vertical passage  128 . A first spacer  144 , illustrated in its dowel chair embodiment, is shown inserted into second vertical passage  126  of the receiving structure (illustrated as another slab  100 ). Spacer  144  includes a seating surface  146  that is partially curved and configured to receive lower surface  136  of the coupling rod  114 . Spacer  144  also includes an alignment surface  148  comprising a projection that is positioned just below the top of second vertical passage  126 . In this configuration, the portion of the top surface  119  of the slab  100  that is adjacent the second vertical passage  126  serves as a landmark segment  150  of the slab  100  for alignment with spacer  144 . 
         [0069]      FIG. 17  illustrates a step of expressing or urging coupling rod  114  partially from the male cavity and partially into the female cavity laterally in a telescoping movement using snake or pipe auger  152 . Preferably, the approximate middle of the lateral length of the coupling rod  114  is extended to an installed position centered on a seam  154  between the slabs  100 , with a portion remaining inside the male cavity and another portion of roughly equivalent length inside the female cavity. In the illustrated extended position, the second end  132  of the coupling rod  114  does not quite reach stopping surface  133 . Nonetheless, stopping surface  133  in this embodiment still serves to stop the coupling rod during extension by snake  152  if it is even moderately overextended beyond its final intended position for installation. Coupling rod  114  is illustrated in this instance, however, in the proper extended position for engagement with second vertical passage  126  at least partially above the second end  132  of the coupling rod  114 , and with lower surface  136  of the coupling rod resting on seating surface  146  of spacer  144 . It is foreseen that a coupling rod may alternatively be flush against a stopping surface in its final extended, installed configuration, which may help to ensure proper lateral positioning of the coupling rod during installation, without departing from the spirit of the present inventive concept. 
         [0070]    Snake  152  comprises an elongated, narrow member configured for insertion through third vertical passage  128  and for pressing against end  130  to move coupling rod  114  laterally in a telescoping action for expression from the male cavity. Snake  152  preferably comprises a composite material such as a metal wire sheathed in rubber, but may also be formed of a mostly homogenous material having properties sufficient to perform the functions described herein. Snake  152  should be configured so that it is rigid enough to be capable of urging coupling rod  114  to telescope within the cavities while also exhibiting enough flex to form a shifting bend  156 ; the shifting bend  156  moves along the length of the snake  152  as snake  152  is pushed and pulled through the male cavity  152 , such that shifting bend  156  remains at the juncture between the male cavity and third vertical passage  128 . Snake  152  additionally preferably has an enlarged head  158  having a wider diameter than the main body of snake  152 , shaped, for instance, to help prevent the snake  152  from deflecting away from the center of the end  130  of the coupling rod  114  and becoming lodged between coupling rod  114  and an interior surface of the male cavity. 
         [0071]      FIG. 18  illustrates a subsequent step of the method of installation described herein in which snake  152  has been removed following proper horizontal or lateral positioning of the coupling rod  114  within the cavities. A second spacer  160  illustrated as a dowel chair in this embodiment is inserted through first vertical passage  124 . Second spacer  160  is constructed similarly to spacer  144 , with a seating surface  162  comprising a curved projection for receiving a segment of the lower surface  136  of the coupling rod  114 . Second spacer  160  also has an alignment surface  164  comprising a projection that is positioned just below the top of first vertical passage  124 . In this configuration, the portion of the top surface  119  of the slab  100  that is adjacent the first vertical passage  124  serves as landmark segment  166  of male cavity-slab  100  for spacer  160 . 
         [0072]    It should be noted that the separation of seating surfaces  146 ,  162  from alignment surfaces  148 ,  164  along the rigid spacers  144 ,  160  is specifically configured for centering the coupling rod  114  vertically within the cavities by taking into account the depth of the passages below the landmark segments  150 ,  166 , and of the diameters of the cavities and the coupling rod  114 , in a manner apparent to one of ordinary skill in the art upon reviewing the Figures. In a preferred embodiment, the centers of the cavities are positioned at approximately the vertical midpoint of the slabs. The spacers  144 ,  160  may be aligned to achieve a pre-determined degree of separation by manual manipulation (i.e., pulling the spacers up by hand in a substantially vertical direction) and/or manipulation using robotic or machine-assisted means. 
         [0073]    It is also foreseen that other types of spacers may be employed for optimizing separation of coupling rods from cavities, without departing from the spirit of the present inventive concept. For example, a spacer may have a seating surface of greater surface area than the projections illustrated in  FIGS. 11-24  and/or that is configured to receive a more permanent and/or greater load from the coupling rod. Such a spacer may also comprise an alignment surface configured for alignment with a different landmark segment, for example with a lower inner surface of one or both cavities, and that may also be configured to bear a load received from the coupling rod by the spacer along the seating surface. Such a spacer may also perform adjustment of the coupling rod by insertion through a different orifice or passage, for example by insertion through seam  154  between the slabs  100 . Such a spacer may still further be aligned with the coupling rod and/or landmark segment by “feel”—such as by feeling for a position in which the alignment surface and/or seating surface settle into proper contact relationship(s) respectively with the landmark segment and/or coupling rod—as well as or as an alternative to, visual alignment/adjustment, without departing from the spirit of the present inventive concept. Spacers may also employ various projections including notches or other structures as a part of their alignment surfaces, preferably where such structures are configured to be complementary with and to engage a structure of the landmark segment for purposes of resting the spacer on the landmark segment. An exemplary projection includes a nib  174  is illustrated in  FIG. 22 , it being understood that the portion of the landmark segment  166  that receives the nib  174  is preferably formed with a notch shaped to substantially complement the shape of nib  174 . A nib may alternatively be formed in the landmark segment and the receiving notch in the projection without departing from the spirit of the present inventive concept. Moreover, it is foreseen that alternative spacers may be inserted into horizontal cavities at pre-determined locations, and may therefore present seating surfaces in proper locations within such cavities so that the step(s) of adjusting the coupling rods may merely involve navigating the coupling rods into position to rest on such seating surfaces. Such adjustment(s) may additionally require lateral manipulation to ensure centering the coupling rods on the seam. In any case, it is preferable that such degrees of separation as are described herein be pre-determined, thus requiring minimal measurement and calculation “on site”; provided that it is foreseen that the seating and alignment surfaces of particular embodiments may be adjustable to suit on site conditions without departing from the spirit of the present inventive concept. 
         [0074]    Spacers  144 ,  160  are illustrated in  FIG. 19  after adjustment of the coupling rod  114 , namely after the rod  114  is manipulated—i.e., through lifting the spacers  144 ,  160  until alignment surfaces  148 ,  164  are level with landmark segments  150 ,  166 —so that coupling rod  114  is vertically centered within male and female cavities. In this preferred embodiment, the separation between the outer cylindrical surface of coupling rod  114  and the inner cylindrical surface of the cavities is ideally 12.7 mm all around. 
         [0075]    To enable uniform separation from all portions of the inner surface of a cylindrical cavity, it is foreseen that the spacer may employ additional seating surfaces for receiving side surface(s) of coupling rods, and corresponding alignment surfaces for toward-and-away adjustment (from the perspective of  FIG. 10 ) of the spacers and coupling rods (i.e., along a z-axis). 
         [0076]    As an alternative to employing such additional seating surfaces and alignment surfaces to achieve proper separation from the cavity along the sides of the coupling rod, it is foreseen that a seating surface intended to aid in adjustment along the y- or vertical-axis may also be used to aid in adjustment and separation along the z-axis. For example, seating surfaces of embodiments of the dowel chair disclosed herein include a projection  146 . This projection may alternatively be formed to comprise a first segment along its middle configured to receive and hold the lower surface  136  of the coupling rod  114 , and may also comprise second and third segments on opposite sides of the first middle segment. The second and third segments may be spring-loaded or similarly biased for extension away from one another and toward opposite sides of the surrounding cavity. The length of extension of the second and third segments may be adjusted so that when the spacer&#39;s seating surface projection is raised vertically to the pre-determined height for proper vertical (y-axis) separation within the cavity as described in detail elsewhere herein, it also holds the coupling rod  114  in a center of the cavity along a z-axis. The collapsible nature of the second and third segments of the projection may further assist the installer when attempting to lower the spacer below the pre-determined height for vertical separation, for example in order to initially catch and seat the coupling rod prior to vertical alignment. 
         [0077]    Returning to  FIG. 19 , after the vertical alignment step, alignment surfaces  148 ,  164  have additionally been brought into contact (not shown) with and made to rest upon portions of landmark segments  150 ,  166 , so that spacers  144 ,  160  may be released by installers without dropping the coupling rod  114  out of its vertically-centered position. This resting relationship is not clearly discernable from  FIG. 19 , but will be enabled for one of ordinary skill in the art upon review of  FIG. 19  and consideration of the general concept of how a projection might be brought to rest on a flat (top) surface. For example, alignment surfaces  148 ,  164  may comprise spring-loaded projections biased for extension beyond the perimeter of vertical passages  126 ,  124 , and which extend outward to rest on the substantially horizontal landmark segments  150 ,  166  when the spacers  144 ,  160  are raised to the pre-determined, aligned height, i.e., slightly above the top surface of the slab. 
         [0078]      FIG. 20  illustrates the insertion of a plug  168  into first vertical passage  124  without substantially disturbing the vertical position of coupling rod  114  within the male and female cavities. Preferably, the position and upper portion of the body of spacer  160  (and  144 ) is configured to conform to the walls of passages  124 ,  126  in an installed configuration, such that insertion of plug  168  minimally disturbs the position of coupling rod  114  upon insertion. 
         [0079]      FIG. 21  illustrates injection of filler or grout  170  into male and female cavities using a grouting line/nozzle  172  inserted into third vertical passage  128 . Filler  170  substantially occupies the space around the coupling rod  114  in the male and female cavities following completion of the grouting process. To complete the grouting process, plug  168  is inserted into vertical passage  124  (i.e., the “proof port”) and grout is pumped through the male cavity and into the female cavity until grout pushes up through vertical passage  126  (i.e., the “exhaust port”) to a point about two inches (2″) from the top surface  119 . Vertical passage  126  is then plugged and grouting is pumped until it pushes up through vertical passage  124  to a point about two inches (2″) from the top surface  119 .  FIG. 22  illustrates the system of  FIG. 21  with the grouting line/nozzle  172  removed from the third vertical passage  128  following completion of this grouting process. 
         [0080]    It is foreseen that filler other than grout may be used without departing from the spirit of the present inventive concept; provided, however, that it is preferred to use a grout such as one comprising grease and epoxy or a similar mixture that provides a distributed, non-permanent (i.e., more easily removable than the material making up main body of the slab  100 ) contact area in support of the coupling rod  114 . 
         [0081]    It is foreseen that the steps for positional adjustment of coupling rods within male and female cavities, and for grouting such cavities, will be repeated for all of the cavities  110 ,  112  (see  FIG. 1 ) in many installation scenarios.  FIG. 23  illustrates an additional finishing step, preferably undertaken after all such cavities have been grouted. This additional finishing step includes inserting grouting line/nozzle  172  into at least one of the receiver ports  118  to inject grout or other filler through receiver ports  118 , through underlying grouting ports  122 , and across bottom surfaces  120  of slabs  100  to generate one or more underlying grout layer(s)  174 . Where such underlying grout layer(s)  174  are formed prior to grouting cavities  110 ,  112 , grout layer(s)  174  may more easily adjust the leveling of the slabs  100  to bring them to a final installed height and/or grade and/or otherwise assist in optimizing the interfaces between the slab bottoms  120  and the ground. Such an ordering of grouting steps may be preferred in certain installation settings, such as where the grade is particularly difficult. In most applications, however, it is preferable that cavities  110 ,  112  are grouted first to preserve the relative position of the slabs  100 , followed by application of the grout layer(s)  174  for long term stability. 
         [0082]      FIG. 24  illustrates yet another finishing step in which the grouting line/nozzle (not shown) has been used to patch some of the remaining surface holes (such as upper segments of vertical passages and receiver ports), it being understood that those remaining visible in  FIG. 24  are preferably also filled prior to completing installation. 
         [0083]    Although the above description presents features of preferred embodiments of the present invention, other preferred embodiments may also be created in keeping with the principles of the invention. Furthermore, these other preferred embodiments may in some instances be realized through a combination of features compatible for use together despite having been presented independently in the above description. 
         [0084]    The preferred forms of the invention described above are to be used as illustration only and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention. 
         [0085]    In this description, references to “one embodiment”, “an embodiment”, or “embodiments” mean that the feature or features referred to are included in at least one embodiment of the invention. Separate references to “one embodiment”, “an embodiment”, or “embodiments” in this description do not necessarily refer to the same embodiment and are not mutually exclusive unless so stated. Specifically, a feature, structure, act, etc. described in one embodiment may also be included in other embodiments, but is not necessarily included. Thus, particular implementations of the present invention can include a variety of combinations and/or integrations of the embodiments described herein. 
         [0086]    In this description, references to an “installed” configuration shall mean that a coupling rod has at least been extended from a male cavity to occupy an adjacent female cavity and has reached an approximate final lateral position therein in preparation for finalizing installation; provided, however, that an “installed” configuration can also refer to a configuration that has been subjected to additional steps such as vertical positioning of the coupling rod, grouting and/or other steps described herein. 
         [0087]    Furthermore, directional references (e.g., top, bottom, left, right, front, back, up, down, etc.) are used herein solely for the sake of convenience and should be understood only in relation to each other. For instance, a component might in practice be oriented such that faces referred to as “top” and “bottom” are sideways, angled, inverted, etc. relative to the chosen frame of reference. 
         [0088]    It is also noted that, as used herein, the terms axial, axially, and variations thereof mean the defined element has at least some directional component along or parallel to the axis. These terms should not be limited to mean that the element extends only or purely along or parallel to the axis. For example, the element may be oriented at a forty-five degree (45°) angle relative to the axis but, because the element extends at least in part along the axis, it should still be considered axial. Similarly, the terms radial, radially, and variations thereof shall be interpreted to mean the element has at least some directional component in the radial direction relative to the axis. 
         [0089]    It is further noted that the term annular shall be interpreted to mean that the referenced object extends around a central opening so as to be generally toroidal or ring-shaped. It is not necessary for the object to be circular, nor does the object have to be continuous. Similarly, the term toroidal shall not be interpreted to mean that the object must be circular or continuous. 
         [0090]    The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention set forth in the following claims.