U.S. patent number 3,683,760 [Application Number 04/862,850] was granted by the patent office on 1972-08-15 for process of infusing liquid into settable porous material.
Invention is credited to Ronald L. Silva.
United States Patent |
3,683,760 |
Silva |
August 15, 1972 |
PROCESS OF INFUSING LIQUID INTO SETTABLE POROUS MATERIAL
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.
Inventors: |
Silva; Ronald L. (Sausalito,
CA) |
Family
ID: |
25339536 |
Appl.
No.: |
04/862,850 |
Filed: |
October 1, 1969 |
Current U.S.
Class: |
404/72;
264/DIG.44; 264/33; 264/317; 264/34; 264/333 |
Current CPC
Class: |
B28B
7/34 (20130101); B28B 7/465 (20130101); Y10S
264/44 (20130101) |
Current International
Class: |
B28B
7/40 (20060101); B28B 7/34 (20060101); B28B
7/46 (20060101); B28b 001/00 (); E01c 007/14 () |
Field of
Search: |
;264/70,33,35,317,333,DIG.43,DIG.44,31,34 ;25/32 ;94/24,1 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: White; Robert F.
Assistant Examiner: Silbaugh; J. H.
Claims
I claim:
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 extending laterally
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.
Description
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 binder to
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, attempts 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 has been 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 3--3
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 8--8
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 of line
10--10 of FIG. 9.
FIG. 11 is a vertical sectional view taken in the plane of line
11--11 of FIG. 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 of FIG.
12.
FIG. 14 is a vertical sectional view taken in the plane of line
14--14 of FIG. 13.
FIG. 15 is a plan view of a modified form of corrugated conduit
structure utilizable in producing a continuous slab of the type
shown in FIGS. 12 and 13.
FIG. 16 is a vertical sectional view corresponding generally to
FIG. 14 showing the modified conduit structure of FIG. 15 in
use.
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 include 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 flexural 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 selective pattern of
holes which provide secondary fluid channels emanating from and
communicating with the primary fluid channels defined by the
elongated corrugations.
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 seen in FIG. 1, the lower most portion 17 of the tube
preferably is provided with no holes therein. Such imperforate
portion may constitute the lower 10 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-thirty-second 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
one-thirty-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 into contact
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 tube without 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 5 in which two such conduits are oriented as noted. In
that arrangement, the conduits shown, designated 19, are generally
circular in cross-sectional 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 one-thirty-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 illustrative.
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 amenable 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 3/8 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.
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