Note: Descriptions are shown in the official language in which they were submitted.
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A COMPOSITE MASONRY BUILDING BLOCK
TECHNICAL FIELD
This invention relates to building blocks, to a method of constructing a
building, a
method of constructing a building block and an assembly of building blocks.
The art to which this invention is generally directed is the art referred to
generally
as "masonry" and "masonry blocks" where building blocks are constructed that
can
be assembled one upon the other to form a masonry wall.
BACKGROUND ART
Baked clay bricks have been known for many centuries but more recently cement
blocks have been manufactured which are used to construct walls of buildings.
Existing concrete blocks as they are currently manufactured are used in walls
by
using a mortar bed and vertical mortar join.
A characteristic of existing concrete blocks is that they are very porous and
it is
considered that this is an economically useful characteristic of concrete
blocks as
currently manufactured because, in order for these to be economic, they are
formed using a very dry concrete mix so that their form is established within
a
mould in such a way that they can then be very quickly removed and left to
then
set separate from a mould.
A conventional concrete block formed in this way is also conventionally formed
with
one or more hollow centres with an open top and bottom.
This of course allows for a bigger overall dimension of a block while keeping
all up
weight for such an overall dimension less than would be the case with a solid
bloq~,.
SUBSTITUTE SHEET (RULE 26) RO/AU
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There still, however, is required considerable skill in laying such blocks
using
mortar beds and having to adjust for each individual block, its relative
position both
vertically and horizontally and laterally one in relation to another.
Further, for reasons of economy a unit size of concrete blocks of current type
are
relatively heavy and this creates a challenge for a skilled bricklayer who
must not
only lift the brick into position, but must also apply mortar to at least one
end of the
brick and then once lifted into position, manipulate this.
This then calls for bricklayers having the ability to be skilled in aligning
such blocks "
but also to be physically strong to achieve this further manipulation.
A further difficulty then arises because of the porous nature of the block and
further
processes, perhaps for instance, rendering of the face of any wall which is
then
more often needed to assist in ensuring a wall. will provide a sufficient
protective
wall for purposes of a building.
It is also true that conventional masonry bricks have existed for a very long
time
indeed and have established a long tradition of ensuring that a masonry wall
is
constructed by using individual bricks laid one upon the other with an
intervening
mortar base of some thickness and especially where this is intended to be a
visible
wall providing, for instance, a visible face, then skill and therefore cost
remain
considerable.
An object of this invention is to propose a block which can be used to
construct
masonry walls, as well as a wall as such and a method of building all of which
facilitate a cost saving at least in the eventual product, for instance when
using a
block, and that such savings can be achieved while at least maintaining a
construction that will meet required building standards.
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DISCLOSURE OF THE INVENTION
In one form of the invention, there is proposed a composite masonry building
block
which has an outer facing material that is formed as a wet cast cement-based
material based material and has a core of a material or materials which are of
less
density than the outer wet cast cement based material.
In preference, the wet cast cement based material is a mixture of an extender
and
a binder.
In preference the wet cast cement based material is a mixture of an extender
such
as sand and a binder such as a cement such as Portland cement.
An advantage of this arrangement is that such a block can by reason of the
nature
of wet cast cement material have an outer surface which _is of low or
negligible
porosity and it also can be made to a high degree of accuracy.
Further, wet cast cement based material as a material can also be therefore
implicitly strong in the context of masonry products so that instead of using
a
mortar bed for joining one_ block upon another, there can now be an adhesive.
A core or body of the block by being faced by the wet cast cement based
material
can be protected and therefore the type of material that can then be used
allows
for a large block in physical size which nonetheless does not then weigh a
proportionately significantly greater weight.
In other words, a desirable weight considering the lifting capacity of a
worker might
be up to let us say typically approximately 14kg, so that by reducing in the
body,
the density of the materials, we then have the possibility of a much larger
block for
the same all up weight.
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In preference in this invention, it is proposed that the material of lighter
density be
expanded plastics material with a binder.
In preference, such a binder can be a wet cast cement based material that then
would be expected to be compatible with the outer surface material.
In preference then, there is proposed a core which is comprised of at least in
the
main, by volume, expanded polystyrene foam and a binder selected from
materials
where these are compatible both with expanded polystyrene foam and the outer
wet cast cement based material whether this is a facing on one face only or on
a
back and front face or as fully surrounding material.
If there is no longer necessity for such a block when being laid to then need
to be
aligned significantly every time on a bed of mortar with an end also of
considerable
thickness of mortar, the skill required for laying such blocks is much less.
By
having accurately sized and implicitly protected blocks means that the job of
laying
then might include coating appropriate surfaces with an adhesive as is
commonly
used in the building industry and then simply placing blocks one upon the
other
where an adhesive layer as compared to a mortar bed will be able to have very
much less thickness.
Because a glue or adhesive material is intended to be a material that of
itself does
not need to and does in fact not provide significant bulk, one can afford to
have a
more expensive material for an effective bonding which then can provide
significant
adhesion between respective matching surfaces.
One of the problems with a block using features described above is that there
still
needs to be a modest level of skill in ensuring that each block is
appropriately
positioned both in vertical alignment and horizontal alignment even though
with
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respect to horizontal alignment, this will depend upon base levels and have
some
dependency upon maintaining only a relatively constant thickness of any
adhesive.
We have described the features according to this invention hitherto without
specifying precisely any of the external shape characteristics of a brick as
far as its
5 external shape is concerned.
In preference then the block has an overall appropriate shape which can
include
curved surfaces but in a preferred example is of rectangular proportions in
which
there are two opposite faces providing an outer face and an inner face, two
end
faces and a top and bottom face.
1.0 If these respective faces are all orthogonally aligned one with respect to
the other
at least generally, then we have a rectangular block.
With respect to the skill required, however, in terms of building a walf using
such
features in a block, it would be desirable if there could be an even greater
reduction in the skill required for the person laying the blocks.
In accordance with this invention then there are further provided one or more
projections in a one of the faces of the block and one more cavities
corresponding
in being a matching shape and position relative to the matching shapes in the
opposed face within a second oppositely positioned face of the block.
In preference, there are a plurality of projections on an upper face that are
spaced
apart an equal distance and such that such projections can be used by matching
cavities by a block which is either aligned at right angles to the first said
block or
overlaps the said block only by a proportion of the total length of the block.
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In preference then, there is a matching relationship between a distance apart
of the
respective projections and the width and length of the block for this to be
achievable.
As was previously stated, this matching would also be matched by appropriate
cavity shapes within an underneath side of a block.
In preference, each projection projects above an otherwise generally planar
shape
of the face and has a shape in cross section which will allow for
compatibility with
an underneath cavity shape, whether that cavity shape is positioned with the
respective block aligned or at right angles to the projection.
While in some cases, this would then allow for projections that might be of a
square cross section or other shapes that are symmetrical about an axis to
allow
for this, in preference, the cross sectional shape is chosen to be circular
and
therefore each projection in preference is of a frusto-conical shape in one
case or
part of a sphere in another.
In preference, the conical shape is chosen so that in a practical sense, when
one
block is located over another, an edge of an upper block can be first rested
on the
top of the underlying block and the top block can be lowered pivotally on its
resting
end so that any cavity then will receive into itself the projection without
snaring an
edge and perhaps breaking off a portion of the projection.
This acceptable manner addresses an issue where if for instance, each
projection
had vertical sides, then an upper block may have to be lowered parallel so as
not
to interfere or break the sides of either the cavity or the projection and
this is
physically much more demanding and in many ways unnecessary.
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Accordingly the sides of the projection and the matching shape of the cavity
includes the inclined sides.
In practice, by having an outer face of the block of.the wet cast cement, this
can be
chosen to be of either low or negligible porosity, and can be very strong and
accurately sized in a way that such accuracy can be maintained through the
curing
process for subsequent reliance then when on a building.
Nonetheless, it is found that there is advantage in providing a small
clearance
between the projecting projections and the matching cavities so that a small
degree of adjustment when being laid on a bed of adhesive can be of
assistance.
Such tolerance is a practical consideration and any discussion in this
document in
relation to accuracy is intended to incorporate any tolerances that are
practical in
the circumstances.
With a block having an all up weight of 14kg, a tolerance allowance of perhaps
1 or
2mm in adjustment either from side to side or along its length has been found
to be
acceptable and provide that fine accurate finessing that is available if
further
accuracy is required in the vertical alignment of a wall.
While we have described a block, we have also realised that in manufacture of
such a block, it is of advantage to provide that the block is made by having a
mould
in which the wet cast cement-based material providing the outer material of
the
block is held during a curing process.
Such a mould can be aligned so that it is in one sense vertical so that facing
sides
are formed while being held in a vertical alignment.
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In another arrangement, a block can be formed by having one side face lower
most
and then the mould is first coated with a wet cement and then either as a
preformed core or otherwise, a material of lighter density is located so as to
be
within a core area of the block to be formed and then a final coating of viret
cast
cement-based material over a back of the core which can then either be rough
finished or fine finished either during or subsequent to a curing at least of
the wet
cast cement-based material.
In a further form there is a method of manufacture which is to locate a
preformed
core of lighter material within a mold, then introducing in. a fluid form wet
cast
.10 concrete so that it is to flow to fill the mold including being around the
core, and
then allowing the wet cast concrete in fluid form to set.
In another preferred case the method can include a first wet cast cement-based
material being inserted into the mould as a layer across a bottom of the
mould,
then a mixture of an expanded plastic material with a binder of sand and
cement is
poured into the mould to be left then to set.
In a further preferred case the method can include a first wet cast cement-
based
material being inserted into the mould as a layer across a bottom of the
mould,
then a mixture of an expanded plastic material with a binder of sand and
cement is
poured into the mould, then a further wet cast cement-based material is poured
on
top of the mixture, with the thus resulting materials being then left to set.
The mix ratios are in preference approximately as follows although these
individual
ratios depend on a number of further factors so that some experimentation is
needed in practise both in relation to the quantities and also the source of
the
commodity items such as plastersizer. The aim is to get a wet mixture that
allows
for a reasonable distribution of the lighter polystyrene beads
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Cement 4.8 kg
Fine beach sand 5.6 kg
3mm polystyrene expanded beads (@20kg=1 m3) 7.2 litres
Plastersizer 120 ml
Super-plastersizer 12 ml
Accelerant 40 ml
Water 1.12 Its
One of the advantages of the arrangement described is that by having a wet
cast
cement-based material with its appropriate strength and its ability to present
a
finished face which has been formed by close association of the casting
materials
with a finished surface of the mould, that subsequent treatment of the block
may no
longer be necessary.
This however, is not to say that we do not incorporate at least in the broader
sense
of this invention other materials that may be of advantage, for instance, an
inclusion of a ceramic tile on an outer face during the casting process.
In a further form the invention can be said to reside in a building block of
cast
concrete which is substantively of rectangular proportions having thereby two
sides, two ends and a top and bottom where the two sides are parallel to each
other and oppositely positioned one with respect to the other, the two ends
are
parallel to each other and oppositely positioned one with respect to the
other, and
the top and bottom are oppositely positioned one with respect to the other and
each have a planar surface which is parallel on,e with respect to the other
and
being further characterised in that there are a plurality of equally spaced
apart
protrusions each being located approximately midway between respective sides
of
the block and extending above the planar surface of the top and a plurality of
equally spaced apart receiving cavities extending into the planar surface of
the
bottom each cavity corresponding in spacing apart so as to receive a one
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protrusion extending into a bottom surface and where the respective
protrusions
and apertures are in respectively mutually corresponding positions.
In further preference it may be further characterised in that the wet cast
concrete
includes polystyrene foam particles.
5 In further preference it may be further characterised in that the
protrusions are
orthogonally symmetrical with respect to the block.
In further preference it may be further characterised in that the cast
concrete is a
lightweight concrete by having a core that is of a less dense than a remainder
of
the block.
10 In further preference it may be further characterised in that the wet cast
concrete is
a concrete with particulate foamed plastics integrated there through.
The invention may also apply to a construction in which a first block as
characterised anywhere hitherto is positioned on a second block as
characterised
anywhere hitherto and the first said block having upwardly directed
protrusions
engaging within corresponding cavities within an underneath face of the second
said block.
In a further form the invention can reside in a block as above where the
protrusions
are of pyramidal shape.
In a further form the invention can be said to reside in a building block
comprised of
at least in the.main by weight cement, and having a core of lighter material
than the
material of a remainder of the block.
In a further form the invention can be said to reside in a building block
comprised of
at least in the main by weight cement, and having a core of lighter material
than the
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material of a remainder of the block, the.core being a mixture of expanded
plastics
and a binder.
In a further form the invention can be said to reside in a building element
including
a body with three sets of, opposedly positioned sides defining thereby a
generally
rectangular shape, the body having a core of a first material and a second
different
material from said first material surrounding the core material providing
thereby an
at least substantially continuous outer surface of said second material, and a
one
side of a one of the set of opposing sides having at least one protrusion
extending
outwardly from a planar surface of the side and at least one cavity in the
further
opposed side of the same set of opposed sides in a position and of a size to
receive and effect an alignment of a further block having the same shape
and.size
of this first defined block by receiving a or the protrusions into the cavity
or
cavities.
In a further form the invention can be said to reside in the above where the
second
material is more dense than the first material.
In a further form the invention can be said to reside in the-above wherein the
second material is made from a mix comprising cement, sand and water.
In a further form the invention can be said to reside in the above wherein the
first
material is made from a mix including cement, sand, water and polystyrene.
In a further form the invention can be said to reside in the above wherein the
protrusion is of frusto conical shape with a wider portion closer to a main
body of
the element.
In a further.form the invention can be said to reside in a the above where the
block
is a composite and wherein the engagement means includes at least one male -
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portion on a first surface, and at least one female portion in a second
surface
opposing said first surface, wherein in use a female portion is adapted to
accept a
male portion for the purpose of joining and causing to be aligned two building
blocks.
In a further form the invention can be said to reside in a building block
being a body
with three sets of oppositely positioned sides a planar shape or a planar base
shape each planar shape or planar base shape aligned to be at right angle to
each
of the other shapes defining thereby a generally rectangular shape, the body
having an inner core of a first material and an outer portion of a second
material
which is of a different density to the said first material providing thereby
an at least
substantially continuous outer surface of said second material surrounding the
said
first material.
In a further form the invention can be said to reside in a building block
being a body
with three sets of oppositely positioned sides each being of a planar shape or
a
planar base shape each planar shape or planar base shape aligned to be at
right
angle to each of the other shapes defining thereby a generally rectangular
shape,
the body having an inner core of a first material and an outer portion of a
second
material which is of a different density to the said first material providing
thereby an
at least substantially continuous outer surface of said second material
surrounding
the said. first material, a one side of a one of the set of opposing sides
having at
least one protrusion extending outwardly from a planar surface of the side and
at
least one cavity in the opposite side of the same set of opposed sides in a
position
and of a size to receive and effect an alignment of a further block having the
same shape and size of protrusion and cavity as this first defined block and
adapted thereby to receive a or the protrusions into the cavity or cavities.
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In preference the protrusions are positioned so that they are spaced apart
central
axis to central axis along a longer length of the block by a distance which is
the
same as the width face to face substantially of the block.
Also each protrusion at an end of a block is a distance away from the end face
of
the block by a distance which to an axis of the protrusion is one half the
distance of
the width face to face substantially of the block.
This allows for each block to be positioned with an interlocking engagement at
right
angles to the elongate direction of an underlying block. In a further form the
invention can be said to reside in an assembly of two blocks each of which is
characterised as eisewhere herein and where the dimensions and shape of a
first
of the blocks are substantially identical to the dimensions and shape of a
second of
the blocks where the first of the blocks is positioned above and aligned to
have a
front and rear face of each define for each a common plane and where the first
block with its bottom face is resting on, directly aligned and adhering by a
thin
adhesive interface extending at least substantially between the two mating
faces.
Brief Description of the Drawings
For a better understanding of this invention, it will now be described in
relation to
embodiments which shall be described with the assistance of drawings wherein:
Fig 1 is a perspective view from above and one side of a block according to a
first
embodiment,
Fig 2 is a perspective view of the same block as in Fig 1 viewed from a side,
Fig 3 is a perspective view of the same block as in Figs 1 and 2 being the
first
embodiment where there is a part cutaway to show an outer facing coat and an
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inner core, and it also shows the arrangement of projections from a top face
and
cavities into a lower face,
Fig 4 is a cross-sectional view of two blocks placed one upon the other in an
interlocking relationship and joined in this case by an adhesive between inter-
engaging faces, the two blocks being shown being the same as the block shown
in
the preceding Figs 1- 3,
Fig 5 is a plan view of the first embodiment as shown in the previous figures,
Fig 6 is a side elevation of the same block as in the previous figures with a
part
cutaway across a bottom portion,
Fig 7 is a side elevation of the same block as in the preceding drawings and
according to the first embodiment and a left hand corner at the bottom being
shown
in part cutaway and the cavities being shown in dotted outline.
Fig 8 is a side elevation of a plurality of blocks placed in an appropriate
interlocking
position with, however, the lower layer of blocks being located on a mortar
bed
which is positioned on the upper face of a supporting foundation,
Fig 9 illustrates the way in which an upper block is positioned and able to be
manipulated so that one corner can be located first, the block lowered
pivotally
about that support without necessarily damaging vulnerable edges of cavities
or
projections,
Fig 10 shows the position resulting from the actions as shown in Fig 9,
Fig 11 illustrates an assembly showing a first course of blocks positioned on
a
mortar bed foundation with a second overlapping across two blocks where a
first of
the blocks is at right angles forming a corner,
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Fig 12 is a further illustration of the way in which a block can be
manipulated and
lowered onto a set of blocks beneath the upper block without damage to either
cavity or projections,
Fig 13 illustrates a mould to be used in the manufacture of blocks according
to a
5 further embodiment,
Fig 14 is an enlarged view of a portion of the view as in Fig 13, except that
there is
now shown a coating of cement to provide a wet cast outer surface to a block,
Fig 15 shows the mould as in Figs 13 and 14 which have now been pivoted to
bring to the two sides together and the mould has been firstly coated with wet
cast
10 cement-based material and filled with a lighter cement and there is a top
to the
mould also coated with wet cast cement-based material to be inserted into the
top
of the material in the mould,
Fig 16 is an exploded view of parts including the die that where there is now
a
preformed core, spaces to keep the preformed core centrally positioned, and
such
15 that there can be a space between the preformed core and the mould in which
wet
cast concrete can be poured and appropriately vibrated as appropriate.
Fig 17 is a larger block from which preformed cores can be cut,
Fig 18 is a perspective view of a further die where the block is to be cast on
the flat
and where a first coating of wet cast cement-based material is placed over a
lowermost face and a remainder of the material is then poured over this and
fills
the die with a back surface being floated,
Fig 19 is an exploded view of the parts providing the assembly of Fig 18.
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Fig 20, 21 and 22 are perspective views of a further embodiment where the
block
is a masonry composite with uppermost protrusions and lowermost cavities being
correspondingly shaped and positioned and being in each case of a shape which
is
semi spherical.
BEST MODE FOR CARRYING OUT THE INVENTION
It is of advantage to establish that the purpose of the invention is to change
significantly the way in which masonry walls or walls of this general type
might be
constructed.
It has hitherto been conventional to use a mortar bed which on the one hand
allows
for significant change and adjustment and alignment of an individual block
once
positioned on the bed but at the same time requires an expertise and skill
firstly to
place the mortar bed in position, and also to keep it supplied to a bricklayer
and
then to ensure that each brick or block as the case might be is then adjusted
so as
to be firstly aligned to the vertical, aligned to the horizontal, and such
that at least
one outer face is aligned with adjacent faces so as to provide a generally
planar
surface or at least a surface which has changes according to a desired
pattern.
Such a strategy has a number of difficulties which have been implicit within
the
building industry for many years.
A first of these is that there is a finite time before a mortar bed will set
so that the
'height a particular wall can be constructed to is limited when underneath
beds
have been not been fully cured.
Further, the constructional strength of a wall depends upon the weight of
individual
members resting on others and only to some extent the physically weak bond
that
might occur between a mortar bed and the brick or block that is positioned on
it.
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There have been increasing difficulties in many cases where skilled
bricklayers are
either in short supply or necessarily require higher rewards for conducting
the quite
strenuous and challenging work.
Referring now to the first embodiment, the block 1 has upper 2 and lower 3
surfaces which include a plurality of protrusions for extending from an
otherwise
generally planar surface 2 and a plurality of cavities 5 inset from the
surface 3.
The arrangement of the protrusions 4 in relation to the surface 2 and the
arrangement of the cavities 5 in relation to surface 3 are such that the
protrusions 4
will generally locate within and generally therefore interlock with the
consistently
aligned-and placed cavities with respect to the protrusions.
Each protrusion is of a common shape and dimension and in this case is of
frusto-
conical shape with the wider base of the frusto-cone lowermost in line with
the
otherwise planar surface of the surface 2 and the top of the frusto-cone shown
for
instance at 6 is co-annular with the lower diameter 7 and such that the
angular
relationship of the side wall shown for instance at 8 is approximately 45 to
the
horizontal or vertical.
The distance between the axis of each adjacent frusto-cone protrusion 4 shown
typically at 9 is the same distance as the width between the broader faces 11
and
12, this width being shown at 10.
Further, each protrusion has its axis so that it is equally distant between
the
respective faces 11 and 12 and the axis at each end is a distance from the end
which is one half of the width of the block.
The cavities 5 having a frusto-conical shape generally matching that of the
protrusions 4 nonetheless have the dimensions in which a one of the
protrusions
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will protrude into a one of the cavities 5 and with a clearance of only a
small
amount, for instance, perhaps 1 or 2 miliimetres typically, one will interlock
therefore and inter-engage with the other to maintain a block above having
these
same characteristics with a block below.
The cavities 5 mirror the relationships as described in relation to the
protrusions 4.
To this extent then they have each a central axis passing vertically through
each of
these and each of these axes is separated from an adjacent axis by the width
10 of
the block.
Further, the end cavity, for instance at 14, has its axis at, within the
tolerances
acceptable within the building industry, one half the width 10 of the block
away
from the end 15.
Further, within each cavity, there is a sidewall 16 which is at 45 to its
central axis
and a top of the respective cavity is a circular area half the diameter of the
lower
circular area coincident with the surface 3.
The block in general is of rectangular shape in this case and has each of the
respective oppositely positioned surfaces at parallel alignments and at right
angles
one with respect to the other.
For such a construction method to be useful, respective alignments of
interlocking
blocks will depend upon accuracy of the interconnecting faces so that instead
of a
mortar bed which will have a thickness of perhaps one or two centimetres, it
is
expected that this will now provide for, if desired, a connection to be made
using an
adhesive or glue where the separation between the respective mating faces is
very
small indeed and might be typically one or two millimetres.
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By having a wet cast outer finish, it makes for closer tolerance and
facilitates a
more accurate wall using this interlocking assembly system.
A next factor however, is that one of the advantages of such a system is that
each
block can be placed into position very quickly and of course, many blocks can
be
placed one upon the other quite quickly because the time required to allow for
a
sufficient adhesion between facing surfaces is not so critical because
additional
weight on top of one another will not of itself significantly harm the
adhesion
between the surfaces even when the adhesion is still uncured.
Nonetheless, there is advantage in having as big a block in physical size as
is
reasonably feasible, given the reasonably requirement of low cost, and in
general
terms, it is considered that a maximum comfortable weight for a bricklayer
might be
14kg.
In order for a block of this type to have a width and have the comparative
length as
shown, there is significant advantage in pro.viding a material which is less
dense
than wet cast cement based material. It is known to have aerated cement but
one
of the difficulties with aerated cement is that it is still quite difficult to
get a
significant reduction in density or at least maintain an aerated state and
maintain
some reasonable distribution of the aeration.
According to this first embodiment, the block 1 includes a core 20 which in
this
case is made from styrene foam mixed with wet castable cement.
A mixture that has been found to be useful is as follows.
Cement (portland cement) 4.8 kg
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Fine Sydney beach sand 5.6 kg
3mm polystyrene expanded beads (@20kg=1 m3) 7.2 litres
Plastersizer 120 ml
5 Super-plastersizer 12 ml
Glenium 51 from Degussa construction chemicals in Sydney Australia is one
example of a super plastersizer
Accelerant (calcium chloride) 40 mi
Water 1.12 Its (this can be increased to 2 or
10 more litres in a typical example)
These ratios have been found to require some experimentation especially the
quantity of water which can be increased until there is sufficient mobility in
the
mixture and the choice and quantity of other components especially the
plastersizer which is available as a commodity from various suppliers. The aim
is to
15 get a wet mixture that will permit the integration of the polystyrene into
the mix and
effect some modest distribution of the polystyrene beads through the mix so
that
the lighter density core can then be formed and set within the outer
surrounding .
Such a core material can be either directly poured into a mould or it can be
preformed with subsequently an outer facing fully surrounding the block or 'it
can in
20 another case be faced only on one side with a dense wet cast cement based
material. The term "cement" is used throughout to describe a material that is
or has
similar properties to portiand cement but can include where the context
permits to
also include the case where the "raw cement" includes a sand or like extender.
While a block 1 has been shown with a line of six protrusions and six matching
cavities, various other modular sizes can also be made and also there can be
some blocks which are appropriate to include so that one side extends along
one
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21
side of a wall, and another part extends along another side of a wall in which
the
two respective walls are at right angles, one to the other.
Such a corner block then is another alternative.
However, there will be as in this first embodiment, a main block the general
dimensions of which are as follows, namely width, height, length, height of
each
protrusion from base to peak, angle of side of each protrusion, difference in
diameter between the cavity and protrusion in each case, all up weight of the
block,
where this is fully encased with an outer wet cast cement-based material.
Fig 4 shows in a typical cross-sectional view how two blocks will be expected
to sit
one on the other and each having an expanded polystyrene foam core and an all
round wet cast facing.
Fig 8 shows specifically the way in which the blocks may in the first instance
be
located on a foundation which doesn't have appropriately positioned
protrusions.
In this case, the blocks can be located on a mortar bed and will require some
skill
in order to set these up accurately and aligned.
This first course however, once laid, then provides the basis for the rest of
the
blocks to be positioned relatively straightforwardly and quickly and with much
less
skill required.
It is a factor in relation to a slight tolerance between the protrusions and
the
cavities that there will still be a small tolerance which even when filled
with an
adhesive appropriate for the purpose, will allow a slight adjustment by the
person
constructing the wall.
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Referring to Figs 9 and 10, the difficulty that is being considered here is
that if one
has a relatively heavy block that is to be located one upon the other, then if
for
instance the cavity and the protrusion each had parallel sides with very
little
tolerance, it would be appropriate to then position the top block fairly
accurately
above the lower one and then lower these once relatively accurate alignment
had
been established.
It is considered that this could be quite awkward and make potential for
breaking
off edges significant with the resultant problem being that the hardened
material
once broken off will reside between the mating surfaces and interfere with an
accurate fit.
By having sloping edges however, one approach that is convenient is to lower a
block by first grounding one end and then simply rotating the block down as
shown
in Fig 9.
It has been established that this will reduce significantly any accidental
breaking off
of parts with interfering then between respective mating surfaces.
Fig 11 is a further illustration of the way in which a first course can be
positioned on
a foundation where in this case the mortar base fills the cavities.
Also, there is an end block 30 so that a full block 31 in this case overlaps
also
entirely the underneath block 32.
This however, would not be the normally desired arrangement and it would be an
in-filled block of appropriate length so that there would be the more normal
overlapping alignment as is shown in Fig, 12.
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In Fig 13, there is a die 40 which is made from two parts, 41 and 42, which
are
joined together by a central hinge so that they can be hinged together into a
shape
that is shown at 15. The point of these dies being separate however, is that
this
allows for a coating of wet cast cement-based material which is made from in
this
case a mixture of portiand cement and sand and the mixture is then to be
liberally
coated over the respective surfaces.
Prior to this step, a release agent is spread over the mould.
The thin layer 43 of the wet cast cement-based material is coated throughout
the
die and in this case also is extended although not specifically shown as such
into
the shapes at 44.
Once fully coated, the two halves 40 ad 41 are brought together and a mixture
of
polystyrene foam and Portland cement and sand together with plastersizers and
accelerants as previously described are mixed together and once mixed are
poured as shown in Fig 15.
Some care needs to be taken to attempt to get an uniform distribution of the
polystyrene foam and it can be of assistance to use well-known binder
plastersizer
agents for this purpose.
Once filled, a cap 45 which is also coated with wet cast cement-based material
and
46 is placed into the top of the mould at 47 and then the whole of this is
then left to
let the wet cast cement-based material generally cure.
Although this provides an arrangement that can provide a product according to
the
embodiment it has one or two difficulties that are now being addressed.
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The first of these is that the polystyrene foam may have a tendency to
separate
from the wet cast cement-based material if the whole is subjected to vibration
for
instance.
The use of vibration is conventional in such applications in order to
consolidate the
wet cast cement based material and to remove pockets of air.
One approach to reduce this difficulty has been to preform a core in which the
precast polystyrene material which is individual peilets or shredded particles
of
polystyrene bound together by a portland cement with extender mixture has been
preformed and then appropriate cores have been cut from such a preformed
batch.
In such a case then, as is shown in Fig 16 the preformed core 50 is positioned
and
kept separate from the outer walls by appropriate spacers such as at 51, 52,
53
and 54 and then otherwise, the mould as described in the earlier Figs 13, 14
and
is used.
In Fig 17, this illustrates the batch method of moulding a core and then
cutting
15 material from this.
A further embodiment however, includes a mould 60 as shown in Figs 18 and 19
which is intended to be adjustably held in position with a clamp 61 which
includes
clamping hold-down bolts 62 and a hold-down frame 63.
The sides of the surround defining the mould which is now an open top mould
includes opposite sides 64 and 65 with appropriate shapes to define the
cavities,
for instance at 66 and protrusions at 67.
The arrangement here is that the first coat on the floor 68 is a coating of
thickness
perhaps of between 1 and 2 centimetres depth fully across the floor and
thereafter
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simply the wet precured mixture of wet cast cement-based material and
polystyrene.
The polystyrene material in this case then, will define the outer thinner
edges of the
block thus formed and the back of the block in this case will not be defined
by a
5 mould as such but can be floated in conventional manner or it can have a
rough
finish which can if needed be ground to a smoother facing finish afterwards.
It is implicit in this technique that the mould is used so that the block
itself is on its
flat and removal of the mould is by individual pieces being able to be
released from
the sides.
10 Referring now to Figs 20, 21 and 22 these show perspective views of a
further
embodiment where the block is a masonry composite with uppermost protrusions
and lowermost cavities being correspondingly shaped and positioned and being
in
each case of a shape which is semi spherical.
The block 70 is of rectangular proportions with a chamfer edge 71 along an
upper
15 edgeofaside72.
The protrusions 73 are each of semi spherical shape and are located at spaced
apart locations which are equidistant from each plane defined by a side 72 and
side 74. Further the spacing is also arranged that when a like block is
positioned
end to end with the said first block then the protrusion 75 at a first end of
the first
20 block will be approximately the spacing distance from a protrusion at an
adjacent
end of the second block. This allows for overlapping with an interlocking
alignment
to'be achieved.
The cavities 76 are each of a corresponding in size and semi spherical shape
to
the protrusions extending from the oppositely positioned top of the block 70,
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extending through the otherwise planar bottom of the block 70 and are
correspondingly positioned so that each is spaced to be equidistant from a
planar
alignment defined by the respective sides 72 and 74 and are also each an equal
distance apart one from the other except that they are approximately one half
this
distance from a plane defined by an end of the block 70.
The block as previously described is a composite masonry block where there is
an
outer facing 77 of a higher density material to provide a harder and tougher
facing
with an inner core material 78 of lesser density. This allows for a larger
block for
given overall sizes where there may be a weight restraint established by
occupational lifting restrictions.
The inner core material is an extended material provided by a mixture of
expanded
plastics material particles, and a binder in this case a cement chosen in this
case
to be portland cement, and sand. It is a difficulty that using a light
material such as
expanded polystyrene is made easier if a superplastisizer, is also used which
assists in mixing.
In use the block shown in this further embodiment is able to be manufactured
as in
any of the earlier described methods and will enable blocks of similar shape,
size
and configuration to be joined by an adhesive so that they can be closely
conforming in position and by having the tougher outer face have a better face
While we have referred to expanded polystyrene as one material in this
application, it is not intended at least in the broadest sense of this
invention that it
should be limited to this.
While a description has been given of protrusions and cavities, and these have
been shown with a circular cross-section in plan, there could be in a broader
sense
some variations from such circularity and even a square shape would be
possible
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although less preferred provided that a cavity would fit over such a
protrusion
equally well from one alignment of an elongate direction of the block to an
alignment at right angles of an elongate direction of a further block to this.
