US 3683760 A
An improved process for effecting setting of porous settable material, such as dry-mix concrete, by infusing liquid into a mass thereof confined in a form. Conduit structure, having one or more primary fluid channels and a plurality of secondary fluid channels by which liquid may be distributed through the porous material to pass therethrough via capillary action, is positioned in contact with the porous mass. The conduit structure in the preferred embodiment comprises corrugated paperboard. The process may be employed in erecting wall sections or laying substantially continuous slabs, such as runways or roadways. The process is utilizable in conjunction with concrete or other settable materials which employ liquid binders in the setting thereof.
Description (OCR text may contain errors)
United States Patent Silva PROCESS OF INFUSING LIQUID INTO SETTABLE POROUS MATERIAL  Inventor: Ronald L. Silva, Green Gulch Ranch, Star Ranch, Sausalito, Calif. 94965 221 Filed: Oct. 1,1969 21 Appl.No.: 862,850
 US. Cl. ..94/24, 264/33, 264/34, 264/317, 264/333, 264/D1G. 44  Int. Cl. ..B28b 1/00, EOlc 7/14  FieldofSearch ..264/70,33,35,317,333, DIG. 43, 264/D1G. 44, 3 I 34; 25/32; 94/24, 1
 References Cited UNITED STATES PATENTS 1,180,472 4/ 1916 Clark ..264/DIG. 43 1,368,756 2/1921 Ross ..264/D1G. 43 1,694,588 12/ 1928 Finley et a1. ..94/24 X 2,123,243 7/1938 Janert ..25/32 X 3,359,875 12/ 1967 Reider ..94/24  3,683,760 51 Aug. 15,1972
Attorney-Flehr, Hohbach, Test, Albritton & Herbert  ABSTRACT An improved process for effecting setting of porous settable material, such as dry-mix concrete, by infusing liquid into a mass thereof confined in a form. Conduit structure, having one or more primary fluid channels and a plurality of secondary fluid channels by which liquid may be distributed through the porous material to pass therethrough via capillary action, is positioned in contact with the porous mass. The conduit structure in the preferred embodiment comprises corrugated paperboard. The process may be employed in erecting wall sections or laying substantially continuous slabs, such as runways or roadways. The process is utilizable in conjunction with concrete or other settable materials which employ liquid binders in the setting thereof.
7 Claims, 16 Drawing Figures PATENTEDAUB 15 mm 3.683; 760
SHEET 2 OF 5 /NVi/V roe PO MLD L, 5/; v4 .5? Fidw W m I|Y,w I14 V 17 H H 6 w /M @W/ BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a process of infusing liquids into a settable mass of porous material, such as a mass of concrete, positioned within a retaining form of predetermined contour. More particularly, this invention relates to the field of infusing liquids into a settable mass by employing conduit structure through which a liquid may be introduced to essentially all areas of a mass of settable material to be distributed through such mass by capillary action upon emission thereof from the conduit structure.
Still more particularly, this invention relates to the field of setting panels or sections or continuous slabs of settable material by first positioning a mass of dry material within a form in contact with conduit structure in engagement with the mass and thereafter utilizing the conduit structure to introduce a liquid binder to all areas of the mass for distribution therethrough by capillary action.
The invention is described herein primarily with respect to an improved process for setting concrete panels, sections or slabs but has utility in setting any porous mass utilizing a liquid binderto set the same. Exemplary reference hereinafter to procedures for producing concrete is not intended to be limiting upon the broader aspects of this invention utilizing other settable materials.
2. Description of the Prior Art Most commonly, concrete slabs, panels or sections are formed by mixing cement, sand and aggregate with quantities of water prior to positioning the wet mixed mass in a form for setting. Such procedure has inherent and well known drawbacks, including segregation of the various components of the mass due to their different constituencies during mixing and pouring. Such segregation results in a panel or slab which is less than fully effective. That and other problems inherent with a wet mixed and poured concrete, well known in the trade, have in recent time focused attention on dry pour processes for casting concrete. That is, attempts have been made heretofore to mix cement, aggregate and sand in forms or molds while still dry and thereafter to add water thereto which is dispersed through the mass via capillary action to effect binding of the constitutuents.
However, prior to this invention, so far as is known, no effective device or procedure was known to insure proper and effective distribution of the liquid binder, at low cost, into the mass so that uniform liquid distribution throughout the mass was insured. For example, at tempts heretofore to utilize compacted sand conduit columns surrounded by a settable dry-mix mass have proved generally ineffective, as have attempts to use canvas hoses, metal spirally wound hollow cable, and the like, as fluid distribution conduits.
The present invention, while utilizing the basic concept heretofore known of infusing a dry settable mass with a liquid binder, effects such infusing by utilizing readily available, inexpensive and expendable materials as the conduit structure. Such conduit structure possesses the ability to effectively distribute the liquid binder to all portions or areas of the dry-mix mass so that effective infusing and thorough wetting of the mass is insured.
So far as is known, no patents disclose the heretofore known infusion procedures mentioned above.
SUMMARY OF THE INVENTION This invention relates to an improved process for setting a mass of dry settable material, such as concrete, utilizing a liquid binder. More particularly, this invention relates to a liquid infusion procedure for setting a mass of dry porous material positioned and compacted in a form or mold. Still more particularly, this invention relates to a process of infusing liquid, such as water, into a compacted mass of dry-mix porous material, such as cement, sand and aggregate, by utilizing expendable, readily available material as conduit structure for distributing a liquid binder to all areas of the mass so that capillary action may thereafter be utilized to complete the distribution and infusion of liquid throughout the mass. This invention further relates to the resulting slab, section or panel produced with such a procedure and to the improved conduit structure employed therein.
This invention has utility in setting panels or slabs of settable material in the horizontal or vertical orientation and also may be employed in setting a substantially continuous slab such as a concrete roadway or airport runway.
It hasbeen found that standard single or double face corrugated sheet paperboard is highly effective for distributing infusing liquid throughout a mass. of porous material positioned in contact with the paperboard. The longitudinal channels formed by the corrugations of the board form primary liquid distribution channels and one face or both paper faces of the board may be provided with suitable holes in communication with the corrugations, such holes forming secondary fluid channels which extend transversely of the longitudinal primary channels for the purpose of effective liquid distribution.
Because of its low cost and ready availability, corrugated paperboard sheets or rolls are particularly well suited for use in the various aspects of the subject process. However, other materials, such as plastics (Styrofoam, for example) which may be molded into a form corresponding to corrugated paperboard, are well suited for this purpose. Thus, while reference is particularly directed hereinafter to double-faced corrugated paperboard, it should be understood that equivalent structures formed from other materials also are contemplated for use as conduit structures within the framework of this invention.
Similarly, while reference is directed hereinafter to the setting of a porous mass of dry concrete, it should also be understood that this invention has applicability in the setting of other dry porous materials in which liquid binders are employed to hold together the constituent components of such materials. For example, the present procedure could be employed for infusing a binder into other building materials such as sheet rock, gypsum plasterboard or the like.
From the foregoing, it should be understood that objects of this invention include the provision of an improved process for setting a mass: of settable material; the provision of an improved process of infusing liquid into a settable mass of porous material, such as concrete; the provision of a process for setting a mass of settable material in panels or sections of predetermined contour or in substantially continuous slabs; the provision of an improved liquid infusion process employing readily available, inexpensive expendable material as a liquid conduit structure for conducting infusing liquid to all areas of the mass being infused; and the provision of an infusion process utilizing corrugated paperboard as a liquid distribution conduit. These and other objects of this invention will become apparent from a study of the following disclosure in which reference is directed to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view, partly cut away, showing a settable panel being cast vertically in place utilizing a first embodiment of an expendable conduit structure for distribution of infusing liquid into the mass of porous material being set.
FIG. 2 is a top plan view looking in the direction of line 2-2 of FIG. 1.
FIG. 3 is a vertical sectional view taken in the plane of line 33 of FIG. 1.
FIG. 4 is a sectional view corresponding generally to the showing of FIG. 1 illustrating utilization of a modified type of conduit structure.
FIG. 5 is a top plan view of the embodiment of FIG. 4 looking in the direction of line 5-5 of FIG. 4.
FIG. 6 is a vertical sectional view, partly cut away, showing another modification for casting a vertical panel in place within a form.
FIG. 7 is a top plan view looking in the direction of line 7-7 of FIG. 6.
FIG. 8 is a vertical sectional view taken in the plane of line 88 of FIG. 6. FIG. 9 is a top plan view, partly cut away of an arrangement for casting a panel in horizontal orientation.
FIG. 10 is a vertical sectional view taken in the plane ofline 1010 of FIG. 9.
FIG. 11 is a vertical sectional view taken in the plane ofline11l1ofFIG.9.
FIG. 12 is a generally schematic view illustrating a procedure for casting a substantially continuous horizontally oriented slab, such as a concrete runway or roadway.
FIG. 13 is a top plan view illustrating the procedure DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is directed to an improved dry pour procedure for casting concrete and like settable materials in place. In the embodiments specifically disclosed herein, the process utilizes a mass of dry compacted porous concrete formed of conventional concrete mix defined by sand, stone aggregate and cement placed within a rigid form or mold while still dry. Such mass is then infused with a liquid binder, such as water, to effect setting of the material in place. Effective distribution of the water to all areas of the mass is insured by utilizing the improved and readily available conduit structure employed. Capillary action distributes the water discharged into the soluble mass to all areas thereof.
By dry pouring and compacting, segregation of the respective constituents of the concrete, which is frequently encountered with wet poured mix, is obviated. Furthermore, when panels are cast flat, the panels may be formed with intricate designs in their upper surfaces, which designs are not disturbed by infusing of water, so that the resulting cast panels may in clude highly decorative appearances not possible when wet pour concrete is used.
Other advantages, including the very important advantage of substantially increased strength, particularly flexural strength, are available. Furthermore, lighter weight structures without loss of strength are producible, and structures having low shrinkage characteristics and smooth finishes, either decorative or nondecorative, are readily obtainable.
Concrete panels may be cast horizontally in place for use in that orientation or for subsequent use in tilt-up arrangements, such as for building walls, or the same may be cast in the vertical orientation for use as retaining walls, building walls and the like. As a further desirable alternative, substantially continuous slabs may be cast horizontally for use in the construction of airport runways and automobile roadways or the like.
The increased strength of dry cast panels or slabs as noted is believed to result from the effective and thorough bonding of the cement to the sand and aggregate particles which results because the smooth infusion of water does not disturb the interlock of the sand particles with the aggregate and concrete particles. Such interlock is known to be adversely affected in wet mix procedures. Improved fiexural strength produced by the dry cast process is particularly helpful in utilization of the dry cast process in forming highways and airport runways or the like in which elongated slabs are utilized.
Before describing the specific embodiments employed in the various aspects of the subject process, a brief description of one desirable conduit structure utilizable with the subject process will be set out. As should be apparent, the conduit structure preferably is provided by a readily available and inexpensive material, of which single double face corrugated paperboard is typical. While hereinafter reference is directed primarily to use of double face board, it should be understood that single face board also can be employed in certain procedures. Many types of commercially available paperboard may be utilized with the present invention.
The sizes and types of corrugated paperboard chosen will vary, depending upon the particular needs of a particular job and, therefore, specific details of a particular type of paperboard are not set out herein. It should be understood that commercial grade corrugated paperboard is well suited for the purposes described herein. In addition to its ready availability and low cost, corrugated paperboard is highly desirable for use as a conduit structure because it may be formed into various shapes as required to meet particular needs.
It should be obvious that the fluted corrugations which impart the name to such paperboard provide a plurality of generally parallel primary fluid channels which extend longitudinally or laterally through the board from one edge thereof to the other. As will be pointed out, for particular purposes, one or both of the paper faces of the board will be provided with a selec tive pattern of holes which provide secondary fluid channels emanating from and communicating with the primary fluid channels defined by the elongated corrugatlons.
Reference is now directed to FIGS. 1 through 3 which illustrate a first embodiment of the subject infusing process and a construction for carrying out the same. These figures illustrate an arrangement for casting a vertical wall in place which is to be used as a building wall section, or as a retaining wall or the like. It should be understood that the size of the wall panel being cast is determined by requirements and the form or mold therefore is constructed accordingly. Such panels, it has been found, can readily be cast in increments approximately 6 feet in length, 4 feet in width, and six inches in thickness, although other sizes, of course, may be produced to meet particular needs.
A rigid form, generally designated 1, is positioned in the orientation desired and held in place by any suitable bracing means, not shown. Such form is generally rectangular in cross section and is commonly formed by opposed plywood side panels 2 and 3 interconnected by plywood end panels 4 and 6 by nailing or adhesively securing the same together. A bottom panel 7 also is provided to complete the form.
After the form 1 has been properly positioned, a fluid conduit structure, generally designated 8, is located internally of the form between the opposed side wall panels 2 and 3 thereof. In the embodiment shown in FIGS. 1 through 3, such conduit structure comprises a preformed self-sustaining hollow tube, which is generally rectangular in cross sectional contour, defined by a sheet of double faced corrugated paperboard including a corrugated central liner 9 and opposed paper surface sheets 11 and 12 respectively, bonded to the liner in known fashion. The sheet of corrugated paperboard is folded upon itself into the configuration shown and is held in such configuration by any suitable adhesive.
As best seen in FIG. 1, the corrugations of the center ply 9 are oriented to extend longitudinally of the tube and provide primary channels for infusing liquid to be introduced there into. The bottom end of the tube preferably is closed off by a plug 13 formed of wood or suitable plastic of appropriate size positioned within the end of the tube and maintained therein by a suitable adhesive.
It should be understood that, after tube 8 is positioned in the form, preferably centrally thereof as seen in FIG. 2, it is surrounded by a mass of dry-mix concrete, designated 14, which is then compacted around the tube to the desired degree of compactness for the particular type of concrete being employed. As noted also from FIGS. 1 and 3, it is preferred that the tube projects above the upper limits of the open top of form 1. In that regard, an extension of 6 inches has been found effective.
The outer paper ply face 11 of the tube, as seen from FIG. 1, has a series of secondary fluid channels formed therein defined by series of holes 16 punched in such paper face before the corrugated sheet is formed into the tubular configuration noted. The holes under certain circumstances may be distributed uniformly along the length of the tube. However, it has been found preferably to selectively orient the holes in a predetermined pattern so that more effective infusion of the concrete mix is insured.
As best seenin FIG. 1, the lower most portion 17 of the tube preferably is provided with no holes therein. Such imperforate portion may constitute the lower l0 percent of the overall height of the tube. Thereafter, extending to substantially the midpoint of the tube, a perforation pattern of approximately eight holes per square inch, each of which is approximately one-thirtysecond of an inch in diameter, preferably is employed. The upper portion of the tube, constituting essentially the remaining 50 percent of the tube, preferably is formed with perforations therein at the rate of 16 holes per square inch, each hole being approximately onethirty-second of an inch in diameter. There is no need for the projecting portion of the tube to have holes therein but perforations may be provided in that portion without detracting from the effectiveness of the procedure if found desirable to facilitate manufacture of the tube.
The staggered perforated pattern noted is provided to counteract the effects of the hydrostatic pressure head of the infusing water to be applied. In the lower portion of the tube where no holes are provided, the hydrostatic head is sufficient to insure passage of liquid through the tube in a weeping fashion permitted by the porous nature of the paperboard. In the remaining lower 40 percent of the tube, the hydrostatic head effects fluid passage outwardly through the openings to a degree not encountered in the upper 50 percent where the perforation pattern is more dense.
With the arrangement shown in which a double faced cardboard tube is employed, the inner face 12 may be maintained imperforate if provisions are made to introduce water longitudinally intocontact with the corrugated inner ply 9 of the tube. However, the inner face 12 may be perforated in any fashion, either intermittently in accordance with the perforation pattern of the outer face 11, or continuously as may be required to facilitate passage of water from the hollow central core 18 of the tube through the inner face 12 thereof into contact with the corrugated center ply 9.
While in FIG. 1, the less densely perforated lower section is shown with holes 16 formed therein in spaced parallel series separated by imperforate parallel bands, it should be understood that a continuous perforated pattern may also be employed if preferred.
Water is inserted into the tube until the same is filled. No particular concern need be given to the amount of water inserted because it has been found that the infusing process described is self metering. If excess water is inserted into the tube which cannot be infused by normal capillary action, the excess water will remain in the tubewithout adversely affecting setting of the concrete panel being cast. After such setting, the water may be removed by any suitable means, such as suction, or it may be allowed to remain in the tube to evaporate in due course. In that regard, the tube itself may be retained within the cast panel or the same may be burned out or otherwise removed as may be desired. In any event, the opening defined by the tube may be left open to provide electrical conduit passageways or the like, or the same may be filled and plugged with any suitable material depending upon the end utilization intended for the cast panel.
While only one tubular conduit structure 8 is illustrated in the embodiment of FIGS. 1 through 3, it should be understood that more than one such conduit may be employed depending on the size of the panel being cast and the particular use intended therefor. In that connection, it has been determined that effective results are produced when infusion of fluid over a horizontal or vertical distance in excess of approximately twelve inches is not attempted. Therefore, placing and number of the tubular conduits oriented in a given form will be determined in accordance with the infusion distance desirability. With a four foot wide panel of the type illustrated in FIGS. 1 through 3, two tubular conduits normally would be employed, spaced approximately 12 inches from the end walls 4 and 6 of the form and approximately 24 inches from each other.
In that regard, reference is directed to the alternative showing of FIGS. 4 and in which two such conduits are oriented as noted. In that arrangement, the conduits shown, designated 19, are generally circular in crosssectional configuration defined by a double faced sheet of paperboard rolled into substantially cylindrical form as noted in FIG. 5. Preferably the end of each tube is closed by a plastic cap 21. The outer paper face ply thereof is formed with a perforated pattern of holes 16 which preferably corresponds to that described previously for the aforementioned tubular conduit 8.
Preferably the tubular conduit structures 19 project above the top of the form 1 in the manner and for the purpose described previously. The spacing between the tubes 19 corresponds to that mentioned previously to insuring effective water infusion into the surrounding mass of dry-mix concrete 14 positioned therearound. As noted, the primary water channels extend longitudinally of the tube to carry water from the top of the form to the bottom thereof. The holes 16 provide the secondary channels which communicate with the primary channels defined by the fluted corrugations of the center ply of the paperboard.
FIGS. 6 through 8 illustrate a modified arrangement for casting a vertical wall panel in place which utilizes a retaining form, designated 1, of the same type as described previously. The conduit structure employed however differs from the tubular structures illustrated in the embodiments of FIGS. 1 through 5. In the present embodiment, such conduit structure, designated 26, comprises a flat sheet of double faced paperboard defined by a central corrugated ply 27, an inner paper face ply 28 and an outer paper face ply 29.
As best seen from FIG. 6, the conduit sheet structure is oriented within form 1 against the side wall 2 of the form in direct contact therewith and is positioned therein so that the corrugations of the central ply 27 extend generally horizontally of the form. In the arrangement shown only inner face ply 28 is provided with a perforated pattern of holes 30. Preferably the perforation patter corresponds to that described previously with the embodiments employing a tubular conduit structure as shown in FIGS. 1 through 5. That is, the lower portion of the sheet conduit structure has no perforations therein while the upper portions of the sheet conduit structure are provided with perforation patterns of increasing density to compensate for the lower hydrostatic head pressure to which the upper portions of the conduit structure are subjected. Preferably the sheet conduit 26 extends above the top of the form a predetermined amount as seen in FIG. 6 for the purpose noted previously.
The sheet conduit structure may be held in place against the inner surface of the form in any suitable fashion such as by using adhesive, staples or tape. Preferably the outer lateral or edge margins of the sheet are closed in any suitable fashion, such as by tape, to restrict and close off the opposite ends of the primary water channels defined by the corrugations therein. Provided in conjunction with the primary water channels defined by the corrugations is a vertical open groove or raceway 31 which extends from the upper end of the sheet and terminates short of the lower end as seen in FIG. 6. Approximately the lower two inches indicated at 32 in FIG. 6 of the sheet do not include the vertical raceway 31.
It will be noted that the face-to-face contact of the sheet 26 with wall 2 of the form effectively produces an enclosed primary water channel defined by raceway 31 through which fluid may be introduced for passage downwardly and then laterally through corrugations of the central ply of the sheet. The facilitate insertion of liquid into contact with the raceway, a plug 33 as seen in FIGS. 7 and 8, extends through wall 2 of the form into communication with the raceway 31. Such plug may accommodate a hose fitting or any other suitable means for introducing water into the raceway.
In the embodiment shown in FIGS. 6 through 8, as noted, the corrugations extend horizontally. It should be understood, however, that the same principle utilizing a flat sheet conduit structure could be employed by arranging the sheet so that the corrugations extend vertically. In such an arrangement, a raceway would be provided horizontally adjacent the top of the form which is connectable with a source of water so that the raceway could be employed to distribute water into each of the vertically extending primary water channels. A similar perforation pattern in the inner face of such a vertically oriented primary channel conduit structure would be employed.
Referring now to FIGS. 9 through 11, a further modified arrangement, in which a panel is cast in the horizontal orientation, is illustrated. In this arrangement, a modified form structure, generally designated 36, is illustrated which is defined by a plywood bottom panel 37, and opposed end walls 38 and 39 and side walls 41 and 42 secured to the bottom panel in any suitable fashion, such as by nailing or adhesive. A divider panel 43 extends between the opposed side walls 41 and 42 as noted.
To facilitate insertion of a conduit structure into the form into engagement with the bottom 37 thereof, it is normally preferable to position the divider 43 in place after the conduit structure 44 is located in place. However, it also is possible to provide suitable spacing between the divider and the bottom so that the conduit structure may be slidably positioned therein after the divider is in place.
The conduit structure 44 employed is a flat sheet of double faced corrugated paperboard of the type described with respect to FIGS. 6 through 8. Such structure includes a central corrugated ply 46, an upper paperface ply 47 and a lower paperface ply 48, the latter being in contacting engagement with bottom 37 of the form. It should be obvious that a single face corrugated board also may be employed if preferred with the corrugations being engaged directly with the form bottom.
One edge 49 of the conduit sheet extends beyond the divider 43 and the ends of the corrugations at such edge are open. However, preferably at the opposite edge 51 of the sheet the conduits are closed in any suitable fashion, such as by tape or adhesive, as are the opposed lateral side edges of the board.
The divider 43 cooperates with end wall 38 of the form to provide a water trough 52 in which a supply of water may be inserted for passage longitudinally through the sheet from end 49 to the other end 51 thereof. It will be noted from FIG. 9 that the inner face 47 of the board is provided with a perforated pattern of holes uniform throughout the length and breadth of the board. Preferably holes at the rate of 16 per square inch, each onethirty-second inch in diameter, is employed. Because there are no hydrostatic head problems encountered with such an arrangement, the selective perforation pattern described with previous embodiments is not required with the present embodiment.
With this arrangement, the water infuses upwardly into the mass of concrete 53 compacted in place above the board within the confines of the form. Such an arrangement permits an intricate pattern (not shown) for design in the upper face of the concrete mass which is undisturbed as water infuses throughout the mass during setting.
In the foregoing embodiments, the improved infusion process has been illustrated in conjunction with the coating of individual panels of predetermined size. However, utility of this invention extends also to the casting in place of a substantially continuous slab of concrete as illustrated in FIGS. 12 through 16. FIGS. 12 and 13 illustrate generally in schematic sequence the utilization of the present process for casting a continuous slab of concrete of the type employed for an airport runway or an automobile highway. In that connection, in accordance with known procedures, opposed guide rails 61 and 62 are secured to a prepared roadbed at the appropriate lateral spacing and extending in the direction in which the slab is to extend when completed.
Rails 61 and 62 provide track surfaces over which known paving equipment will ride. A suitable vehicle designated 63 may be provided on which is positioned an elongated roll 64 of double faced corrugated cardboard sheet of the type described previously, the upper surface of which is formed with a regular consistent and continuous perforated pattern of holes corresponding to that described with respect to FIGS 9 through 11 previously. The corrugated roll 64 is mounted on any suitable trunnion structure 66 so that the sheet is free to be unreeled as vehicle 63 moves along the guide rails 61 and 62.
Thus, a substantially continuous predetermined length of corrugated paperboard which defines the infusing liquid conduit structure may be positioned directly upon the previously prepared roadbed subsurface 73 by driving vehicle 63 along the rails. Following laying of the elongated sheet 67 of paperboard, additional opposed form sections 68 and 69 are positioned in engagement with the rails 61 and 62 to overlie opposite marginal portions of the sheet as best seen in FIG. 14. Such form sections comprise essentially vertical walls 70 having spaced ribs 70' positioned to engage the rails 61 and 62 to maintain the walls in proper upright orientation.
The purpose of such from sections 68 and 69 is to define water troughs 65 in conjunction with the rails 61 and 62. Such form sections may be positioned in sections and secured together in any suitable fashion. If desired, such forms may be closed off in longitudinal segments so that each such form provides a separate water trough in conjunction with its associated rail.
In any event, after forms 68 and 69 are positioned in place, another vehicle 71 may pass over rails 61 and 62 and a mass 72 of dry-mix concrete is spread thereby over the paperboard conduit sheet 67 between the limits defined by the opposed forms 68 and 69. Spreading of the dry-mix concrete in an even layer may be effected by available machinery or manually. Thereafter, the concrete mass is compacted while in dry form by any suitable vehicle, such as a roller vehicle 74. After the dry-mix concrete has been compacted, another vehicle 76 travels along the rails 61 and 62 and distributes infusion water into the water troughs 65 defined by forms 68 and 69 with the associated rails 61 and 62. Because of the self metering capability of the dry-mix concrete, careful regulation of the amount of water introduced into the troughts need not be of great concern.
It should be understood that the corrugations in the paperboard conduit sheet structure 67 are positioned to extend transversely of the direction in which the concrete strip is being laid. Also. opposite ends of the corrugations at the opposite margins of the paperboard sheet are open and communicate with the respective water troughs so that water may pass into the primary channels defined by the corrugations inwardly toward the center of the strip for subsequent distribution through the perforated upper face thereof and then by capillary action into the mass of concrete positioned thereover. Following setting of the slab, the forms 68 and 69 and the rails 61 and 62 may be removed in known fashion and an adjacent slab or slabs similarly positioned until a runway or highway of desired width has been produced.
With the arrangement described, a substantially continuous casting process may be effected with the steps proceeding in rapid succession one after the other in the arrangement shown.
It will be understood that, if a continuous length of paperboard sheet is positioned beneath the concrete mass being poured, the resulting. concrete slab will be initially isolated from the earthen subsurface 73 by the paperboard strip. Such strip ultimately will deteriorate thereby leaving a small void between the subsurface and the concrete slab. Such a condition would not create problems not presently encountered with conventional wet pouring methods which, due to shrinkage, produce voids between the concrete slab and the earthen subsurface.
As shrinkage exists, either of the earthen subsurface or in the concrete itself, or as roadbed deterioration caused by water errosion and the like is encountered, cracking of conventionally laid wet poured concrete slabs is not uncommon. However, if it is desired to even further minimize the possibility of such crackling with the present procedure, it is merely necessary to utilize discontinuous lengths of paperboard conduit structure. For example, as seen in FIGS. 15 and 16, a modified sheet of paperboard 76 in which the primary channels defined by the corrugations extend transversely of the direction of laying the same, may be provided. Such sheet is formed with spaced, intermittent open recesses 77. The configuration of and location of such recesses 77 may be provided as required to meet a particular need. As a result, when a mass of concrete 78 is positioned as noted previously in overlying relationship with respect to the paperboard sheet, a portion of such concrete is received within each recess 77 in direct contact with the underlying earthen subsurface 81. Thus, upon subsequent deterioration of the paperboard sheet 76, direct contact of each portion 79 of the concrete slab with the earthen subsurface greatly minimizes the possibility of cracking of the slab.
It should be obvious that a discontinuous pattern in the paperboard sheet may be effected in various ways, such as by using discrete lengths of paperboardspaced from each other at regular intervals or by using various open patterns of which the elongated generally rectangular opening 77 shown in FIG. 15 is merely illustratlve.
As noted previously, the present process has wide applicability in its use and is not limited to any particular type of dry-mix concrete so long as the same is arnenable to infusion by capillary action as noted. By way of specific example, and without intending to be limiting, the present invention has been found effective when utilized with a dry concrete mixture comprised of sand, cement and aggregate, the latter of which is not beyond a size of three-eighths inch in diameter. By using such a concrete mix, made up one part cement with an equal part of '74; inch gravel, and three parts of sand, desirable results have been obtained by compacting the same to approximately 138 pounds per cubic foot (the resulting weight of which is approximately 27 pounds per test cylinder). Test specimens of such mix compacted as noted to approximately 12 inches in height and a diameter of approximately 6 inches were treated with a hydrostatic head of water of 10 inches. Such test specimens, infused with cylindrical conduit structures of the type described previously, have produced excellent results at infusion rates of approximately 2 pounds of water in a 5 hour period. The infusion rate may be speeded up or delayed as desired, depending upon the perforated hole pattern employed with the conduit structure.
It has also been found that leaving specimens in contact with infusing water for an additional 8 to 13 hours may result in infusion of several ounces of additional water but it has been determined that such additional exposure to infusion liquid does not result in any appreciable increase in infusion water quantities.
Such tests have indicated that dry mix compacted to approximately 138 pounds per cubic foot density having weight of approximately 27 pounds per test cylinder will gain approximately 1,000 grams of water during a 5 to 6 hour infusion exposure time. Such tests have further indicated that an infusion distance of approximately 12 inches from a source'of infusing water is perhaps the optimum which can be employed with the present process. However, by judicious placing of conduit structures, infusion of masses of concrete of almost any size or configuration can be effectively insured.
Having thus made a full disclosure of this invention, reference is directed to the appended claims for the scope of protection to be afforded thereto.
1. A process of forming a generally continuous elongated slab of settable material, such as concrete, in a series of successive steps in a generally continuous operation, comprising preparing a roadbed in a predetermined location determined by the direction in which said slab is to extend; positioning opposed outer guide rails along opposite sides of said prepared roadbed; positioning fluid conduit structure in elongated sheet form within said guide rails on said roadbed, said sheet conduit structure including primary and secondary fluid channels extending therethrough into communication with an upper surface thereof; positioning inner form sections within said opposed guide rails in overlying relationship with opposite marginal edge portions of said sheet conduit structure, said inner form sections and said guide rails defining longitudinally extending fluid troughs along said opposite margins of said sheet conduit structure; covering said conduit structure between said inner form sections with a layer of dry settable material; compacting said layer of dry settable material; and introducing predetermined quantities of fluid into said fluid troughs for distribution therethrough into contact with substantially all areas of said layer of dry settable material for diffusion upwardly therethrough by capillary action.
2. The process of claim 1 in which said fluid is introduced into said fluid troughs simultaneously at more than one location.
3. The process of claim 1 in which said sheet conduit structure is discontinuous in the direction in which said slab is to extend so that predetermined portions of said settable material come in direct contact with said prepared roadbed.
4. The process of claim 1 which includes forming said sheet conduit structure from a generally flat sheet of expendable corrugated paperboard in which said primary fluid channels are defined by the corrugations thereof which extend transversely of said inner form sections and said secondary fluid channels are defined by a uniform series of holes provided in the paper face ply which defines said upper surface of said sheet across substantially the full length and breadth of said face ply so that said fluid is meterable upwardly through said sheet over substantially its entire upper surface to insure uniform infusing of said settable material by said fluid.
5. A process of directly infusing fluid into a horizontally oriented settable mass of dry porous material, such as concrete, which hardens when mixed with fluid, such process being carried out in a series of successive steps in a substantially continuous operation to form a generally continuous slab of said settable material, comprising preparing a roadbed in a location determined by the direction in which said slab is to extend;
providing a form structure of predetermined contour in which said settable material is to be set; horizontally orienting said form structure to extend along opposite margins of said roadbed; positioning a substantially rigid, generally flat preformed, self-sustaining sheet which defines a hollow conduit structure within said form structure, said form structure at least partially overlying opposite lateral edge margins of said sheet, said sheet conforming generally to the configuration and size of said form structure and having a plurality of primary fluid channels extendingjlaterally horizontally internally thereof and a plurality of secondary fluid channels in communication with said primary channels and branching upwardly therefrom and extending through the upper surface of said sheet which is to be in contact with said settable material in said form structure; introducing a predetermined quantity of said settable material into said form structure to overlie and cover said surface of said sheet; compacting said settable material in said form structure on said sheet; introducing fluid substantially uniformly and in controlled fashion into said settable material through said lateral edge margins of said sheet for distribution through said sheet over substantially the entire extent of said surface of said conduit structure by providing hydrostatic heads adjacent said lateral edge margins of said sheet defined by quantities of said fluid introduced into said sheet and meterable thereby substantially uniformly through said primary channels and then upwardly and outwardly through said surface of said sheet through said secondary channels; said fluid being introduced into said sheet from fluid troughs defined by said form structure along said opposite margins of said roadbed; and maintaining said hydrostatic heads defined by such fluid to insure continued metering of said fluid through said surface of said conduit structure through said secondary channels until said settable material is thoroughly infused by said fluid for the full length of said slab.
6. The process of claim 5 which includes forming said sheet conduit structure from a generally flat sheet of expendable corrugated paperboard in which said primary fluid channels are defined by the corrugations thereof and said secondary fluid channels are defined by a uniform series of holes provided in the paper face ply which defines said upper surface of said sheet across substantially the full length and breadth of said face ply so that said fluid is meterable upwardly through said sheet over substantially its entire upper surface to insure uniform infusing of said settable material by said fluid.
7. The process of claim 5 in which said sheet conduit structure is discontinuous in the direction in which said slab is to extend so that predetermined portions of said settable material come in direct contact with said prepared roadbed.