Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a method of fil.ling or partly filling a
hole in the ground.
The invention is especially, but not exclusively, applicable to
holes in roads, airfield runways, car racing tracks, paths and other ground
surfaces made wholly or in part of concrete; it is also applicable to holes
formed during the construction of a building or the erection of an ups-tanding
structure for foundation purposes.
It is an object of the invention to provide an improved method of
filling or partly filling a hole in the ground, which method can be effected
in substantially less time than methods hitherto proposed and used, is sub-
stantially more economical in materials than such methods and is therefore
substantially cheaper.
According to the invention the method comprises the steps of: (a)
partly filling the hole with a plurality of separate bodies of concrete or
other material in its manufactured state and/or of rock, granite or other
material in its natural state; (b) applying over the partially filled hole a
flexible fluid-tight impermeable covering and sealing the covering to the
surface of the ground around the hole to form a substantially fluid-tight
enclosure; (c) evacuating air and any other fluid from the~fluid-tight
enclosure; (d) allowing a hardenable mixture of a cold setting synthetic resin
in a flowable state and a filler to enter the evacuated enclosure until harden-
able mixture substantially fills the interstices between said separate bodies
and at least partially fills the remaining space in the hole; and (e) permit-
ting the hardenable mixture to set and bond firmly to the surfaces of said
separate bodies.
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Preferably, before introduction of the hardenable mixture, inter-
stices between the separate bodies are partly filled wlth a coarse aggregate
or other multiplicity of separate small bodies, the hardenable mixture then
being introduced substantially to fill the remaining spaces in the interstices
and wholly or partially fill the remaining space in the hole.
The improved method ensures that: the hardenable mixture not only
substantially fills the interstices between the separate bodies but also
enters cracks, pores, and other voids in the surfaces of said bodies, and when
present of coarse aggregate, and thereby when it sets will effect a very strong
bond with the bodies, and coarse aggregate.
Since the hole is partly filled with separate bodies, or with
separate bodies and coarse aggregate, the amount of hardenable mixture required
to fill said interstices and wholly or partially fill the remaining space in
the hole is substantially less than the amount of concrete in a plastic state
that would otherwise have been required to fill the hole; the saving in cost
of material can therefore be substantial. Furthermore, the hardenable mixture
of cold setting synthetic resin and filler, unlike conventional concrete,
effects a very strong bond with the separate bodies, and when present with the
coarse aggregate, and will harden to a sufficient extent to~support traffic or
to permit construction work to commence in a few hours only.
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Other operating steps that may be employed in introducing the
hardenable mixture of cold setting synthetic resin and filler into the hole
using the aforesaid vacuum impregnation technique are described and claimed in
the specifications of our Canadian Patent No. 99~616, our British Patents Nos.
1479020, 1480718 and 1490102, and of our Canadian Applications Serial Nos.
288893 and 309196.
To eliminate any risk that air will be introduced into the evacuated
enclosure in the hardenable mixture, when preparing the mixture, the synthetic
resin and filler may be mixed together under vacuum.
A preferred coarse aggregate is gravel because of its flow properties
but, in some circumstances, stone or granite chippings may be employed.
It is preferred to use, as the cold setting synthetic resin, poly-
ester resin because it has a very short setting time, usually about two hours,
but in some circumstances where a short setting time is not of first priority,
epoxy resin is preferred because there is less risk of cracks forming in the
resin due to shrinkage of the resin as it hardens.
One preferred hardenable mixture comprises a
synthe~ic res~n/flller mixture i~ the proportion 1:1
to 2:1, by weight. A preferred hardenable mixture
consists of 1 part by weight polyester resin and 1 part
by weight calcite. Other fillers that may be employed
include granular bauxite and armosphere, a material consisting
of tiny hollow spheres of glass which are an extract of
pulverised fuel ash.
As previously indicated, the method of the present
invention is especially, but not exclusively, spplicable to
filling a hole in a road or other ground sur~ace made wholly
or in part of concrete. Where, in a road fabricated ~rom
separately formed slabs of concrete, a concrete slab cracks
and a part or parts of the slab sinks or sink below the normal
running surface of the road, it is the usual practice when
repairing the road, to break up the damaged slab, to remove
the pieces of broken concrete in order that the fault in the
road foundation which caused the concrete slab to crack and
sink can be identified, to repair the fault in the road foundation
and to re-fill the resultant hole in the road with concrete
in a plasti-c state which must then be allowed to harden,
For several reasons such a method of road repair is extremely
uneconomical and expensive Firstly, during the time the
road repair is being effected, traffic has to be diverted
and apart from congestion and consequential delay to traffic
this may entail employing police to control the diverted traffic
and may cause considerable inconvenience to occupants of houses
and other premises in the vicinity of the repair and/or
diversion. Secondly, the broken pieces o~ concrete
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must be conveyed from the site of the road repair
and sufficient concrete mixed on or transported to
the site for filling the hole. Thirdly, after the
hole has been filled with concrete time must be
allowed for the concrete to harden to a sufflcient ~
extent for it to support traffic; this may take anything
up to ten days and even longer, depending on the size
and depth of the hole, the properties of the cement and
the proportions of' the mix. Thus, the usua~ method of
effecting a road repair is extremely costly, not only in
the amount of concrete employed, but also in the time
necessary for a satisfactory repair to be made and for
the road to become serviceable.
The method of the present invention is especially
applicable to road repairs because it has the important
advantages that the broken pieces of concrete slab originally
forming a part of the road can constitute the separate bodies
with which the hole is partly filled and therefore do not
have to be conveyed from the site; indeed in some circumstances
after the sunken concrete slab has been broken into pieces3
at least some of the pieces of concrete need not be removed
from the road. Moreover, since the hardenable mixture of
synthetic resin and filler hardens to a sufficient exten~
to support traffic in a few hours, the repair of a road can
be effected in a matter of hours, say one night, as opposed
to several days, thereby providing a considerable saving in
expense and inoonvenience.
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Other applications of the method of the present
invention include the fabrication of foundations ~or
towers, ma~ts, posts and other upstanding structures of
the kind in which a lowermost part of a leg of a tower
or mast or of a pole i positioned in a hole in the ground,
that hitberto has been ~ille~ with concrete. By filling
such a hole using the method of the present invention, there
is not only a saving in material but the foundations 50
formed harden so quickly that further construction o~ a
tower or other structure can continue within a matter of
hours.
The invention will be further ;llustrated by a
description, by way of example, of a preferred method of
repairing a sunken part of a concrete road with reference
to the accompanying drawing, in which:-
- Figure 1 is a ~ragmental longitudinal section
through a lateral joint between two concrete slabs of the
road,
Figure 2 is a similar view in which one of the
concrete slabs has fractured; and
Figures 3 and 4 are stages in the method o~
repairing the road.
Referring to Figure 1, the two concrete slabs
1, 2 of the lateral joint 3 are subject to a differential
deflection on passage o~ heavy traffic due to the formation
of a void 4 between the slabs and the sub-grade 5. Methods
of introduci.ng hardenable material into such a vo d in a
road are the subject of our co-pending Canadian Patent
Applications Serial Nos. 288893 and 309196.
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In some circumstances be~ore the void 4 can be
sakisfactorily ~illed with hardenable material) the traffic
load is so large and the dif~erential defleotion becomes so
great that actual fracture o~ the concrete slab l occurs with
settlement of the broken portion 6 of the slab in the void3
as shown in Figure 2. As already described the current
practice in repairing such a damaged road is to break the
broken portion of concrete slab into pieces, remove these
pieces from the site and, a~ter repairing the ~ault causing
the void, ~illing the space vacated by the bro~en portion of
concrete slab with concrete in a plastic state.
In the method according to the present invention
after breaking into pieces 7 of concrete the detached portion
6 of the slab 1 several o~ the pieces are removed to permit
inspection of the foundation sub-grade 5 and, i~ necessary,
to effect such repair as is required; pieces of concrete are
then replaced in the hole 8 in such a way that all the pieces
7 lie below the plane of the road surface as shown in Figure 3.
Holes 13 are drilled through the slab 2 into the part of the
void 4 underlying this slab~ Several plastics tubes 9 that are
to constitute injector nozzles are inserted around the periphery
of the hole 8 in such a wa~ that eacb nenetrates ~ee~ down into
the original void. The interstices between the pieces 7 of
concrete are then partly filled with gravel aggregate 10, e.g.
t~lree-quarters o~ an inch or less, the aggregate being levelled
off slightly below the original road level. As is shown in
Figure 4, a flexible ~luid-impermeable polythene sheet ll having
one or more than one outlet 12 for connection to a vacuum pump
(not shown) and having adjacent its boundary edges a separately
~ormed pre~ormed endless hollow wall 14 that has outlets 16
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and that surrounds~ and opens towards and is sealed to,
the part of the road immediately surrounding the hole 8,
is fitted over the hole and over the drilled holas 13
and boundary edges of the sheet are sealed by mastlc sealant or
adhesive tape 15 to the road to form a substantially ~luid-
tight enclosure incorporating the hollow wall.
Air and any other ~luid is then evacuated by a
vacuum pump or pumps ~rom the part o~ the void 4 underlying
the slab 2 through the holes 13, ~rom the hollow wall 14
and from voids within the covered part o~ the road through
the outlets 12 and 16 and a hardenable mixture consisting
of e~ual parts by weight of polyester resin and calcite is
introduced through the in~ector tubes 9 until it oozes ~rom
the holes 13 and from the sur~ace o~ the gravel aggregate
10 and forms a continuous surface, under the flexible sheet 11.
Any air or other ~luid that may leak under the sheet 11 ~rom
beyond itssboundary edges enters the hollow wall 14 and is
extracted t~rough the outlets 16.
A small positive head o~ hardenable mixture is
maintained on the in~ector tubes 9 until the hardenable
mixture gels and then, before the hardenable mixture hardens,
the injector tubes and flexible sheet 11 are removed and any
holes left by extraction of the injector tubes are topped up
with hardenable mixture. While the surface o~ the hardenable
mixture is still tacky bauxite is sprin~led li~erally over the
hardenable mixture to provide an anti-skid sur~ace. A~ter
approximately two hours the hardenable mixture will have
bonded ~irmly to the surface o~ the pieces 7 and gravel aggrega~e
10 and will be hardened to a su~icient extent to support tra~ic.
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