IE84379B1 - Improvements in and relating to decorative load bearing blocks - Google Patents
Improvements in and relating to decorative load bearing blocks Download PDFInfo
- Publication number
- IE84379B1 IE84379B1 IE2000/0147A IE20000147A IE84379B1 IE 84379 B1 IE84379 B1 IE 84379B1 IE 2000/0147 A IE2000/0147 A IE 2000/0147A IE 20000147 A IE20000147 A IE 20000147A IE 84379 B1 IE84379 B1 IE 84379B1
- Authority
- IE
- Ireland
- Prior art keywords
- block
- blocks
- building block
- decorative
- decorative building
- Prior art date
Links
- 239000000203 mixture Substances 0.000 claims abstract description 31
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 15
- 239000011707 mineral Substances 0.000 claims abstract description 15
- 239000004568 cement Substances 0.000 claims abstract description 14
- 210000000088 Lip Anatomy 0.000 claims abstract description 8
- 230000002093 peripheral Effects 0.000 claims abstract description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 239000003638 reducing agent Substances 0.000 claims description 2
- 239000004567 concrete Substances 0.000 abstract description 21
- 239000004570 mortar (masonry) Substances 0.000 abstract description 6
- 230000001788 irregular Effects 0.000 abstract description 2
- 239000004575 stone Substances 0.000 description 19
- 230000001603 reducing Effects 0.000 description 9
- 239000000463 material Substances 0.000 description 7
- 238000006722 reduction reaction Methods 0.000 description 7
- 239000000047 product Substances 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 230000002745 absorbent Effects 0.000 description 2
- 239000002250 absorbent Substances 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 239000011449 brick Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000003319 supportive Effects 0.000 description 2
- 206010018987 Haemorrhage Diseases 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 239000011398 Portland cement Substances 0.000 description 1
- 230000000996 additive Effects 0.000 description 1
- 239000012237 artificial material Substances 0.000 description 1
- 230000000740 bleeding Effects 0.000 description 1
- 231100000319 bleeding Toxicity 0.000 description 1
- -1 bottles etc. Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000005352 clarification Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000001419 dependent Effects 0.000 description 1
- 230000002452 interceptive Effects 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000010445 mica Substances 0.000 description 1
- 229910052618 mica group Inorganic materials 0.000 description 1
- SCKXCAADGDQQCS-UHFFFAOYSA-N performic acid Chemical compound OOC=O SCKXCAADGDQQCS-UHFFFAOYSA-N 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 239000008262 pumice Substances 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000004449 solid propellant Substances 0.000 description 1
- 238000010186 staining Methods 0.000 description 1
- 230000004580 weight loss Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B2/00—Walls, e.g. partitions, for buildings; Wall construction with regard to insulation; Connections specially adapted to walls
- E04B2/02—Walls, e.g. partitions, for buildings; Wall construction with regard to insulation; Connections specially adapted to walls built-up from layers of building elements
- E04B2002/0256—Special features of building elements
- E04B2002/0271—Building elements with the appearance of rock layers
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C1/00—Building elements of block or other shape for the construction of parts of buildings
- E04C1/39—Building elements of block or other shape for the construction of parts of buildings characterised by special adaptations, e.g. serving for locating conduits, for forming soffits, cornices, or shelves, for fixing wall-plates or door-frames, for claustra
- E04C1/395—Building elements of block or other shape for the construction of parts of buildings characterised by special adaptations, e.g. serving for locating conduits, for forming soffits, cornices, or shelves, for fixing wall-plates or door-frames, for claustra for claustra, fences, planting walls, e.g. sound-absorbing
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
- E04C2/02—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials
- E04C2/04—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of concrete or other stone-like material; of asbestos cement; of cement and other mineral fibres
- E04C2/041—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of concrete or other stone-like material; of asbestos cement; of cement and other mineral fibres composed of a number of smaller elements, e.g. bricks, also combined with a slab of hardenable material
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
- E04C2002/005—Appearance of panels
- E04C2002/008—Panels with the appearance of a natural stone wall
Abstract
ABSTRACT DECORATIVE BUILDING BLOCK A block according to the present invention comprises a load bearing concrete or mortar body 1 onto the surface of which is provided a decorative facing 2 comprising a number of flint or similar mineral pieces 3 set into concrete. The mould has a peripheral lip extending from the upper surface into which pieces of flint or similar mineral pieces 3 can extend. the hand set mineral pieces provide a slightly irregular shaped periphery to the top surface of the facing block. Blocks can be then matched such that protrusions from one block can be aligned with indentations on adjacent blocks. Around the periphery of the 1oad—bearing block is a frog 5 of semi- circular or other cross-section. The load bearing body comprises a mixture of cement and lightweight aggregates. [Figure 1] IE000147 IEOOOI47
Description
IMPROVEMENTS IN AND RELATING TO DECORATIVE LOAD BEARING
BLOCKS
DORSET FLINT & STONE BLOCKS LIMITED
IMPROVEMENTS IN AND RELATING TO
DECORATIVE LOAD BEARING BLOCKS
This invention relates to facing blocks of the type used in the construction of
buildings and structures to provide natural stone effects generally on the external surfaces
of the building or structure but which can also be used internally as decor finishes or
feature claddings or coverings such as fireplace surrounds etc.
In older villages and towns it is not uncommon to find buildings and structures
built with a decorative arrangement of natural stone, pebbles, flint and the like laid up with
mortar. The random arrangement of differently shaped and/ or coloured pieces results in
an attractive ruralistic appearance and is often admired by onlookers.
Over the years, this natural stone and mortar method has been used less and less
primarily because it is a labour intensive, time consuming building method, which is highly
reliant on dry conditions for its successfiil completion. Consequently, it is an expensive
building process. In recent years, such methods have been replaced by cheaper, faster
more versatile building methods and materials such as bricks, concrete building blocks and
various prefabricated structures.
In recent years products have become available which combine the aesthetic
properties of natural stone methods with the convenience of modern methods. An
example of this type of product is the Dorset Flintblock, one of a range of products
manufactured by Dorset Flint and Stone Blocks Limited. These products consist of
moulded blocks of concrete into one surface of which a decorative arrangement of pieces
of natural stone, pebbles, flint and the like are hand-set. The blocks can then be assembled
into a building structure using methods similar to those conventionally used with plain
concrete blocks, the decorative surface facing externally in the wall stmcture to provide
an appearance of a natural stone built wall. Similar products incorporate pebble, cobble
and sand stone facings. Blocks such as these can be used in load bearing applications thus
minimising the need for internal structural support.
Conventionally, simple square or rectangular shaped metal moulds are used to
shape the blocks, the moulds being disassembled from the set concrete to release the
block. Different shapes or patterns of stone work can be achieved by inserting shaped
polystyrene pieces in strategic places about the mould to define the desired shape of the
end product or different mould shapes can be used if required.
The set pieces of stone may be treated to improve or change the natural
appearance of the stone, for example by staining, polishing or varnishing or it can be
worked with tools which is generally known as dressing the stone. Alternatively the stone
may be presented as it appears naturally, or undressed. Alternatively other materials may
be set as required.
The simple shape of these stone faced blocks render them far easier to assemble
into building structures than randomly shaped stone pieces. The blocks can be assembled
using a11—weather techniques conventionally used for plain concrete block and brick
building providing a simple and cost elfective route to an attractive, traditional or modern
decorative external wall surface.
One problem with these blocks arises in the additional weight added to a typical
sized concrete block by the inclusion of stone pieces on the surface. Often the mo st
commonly used sizes of blocks are too heavy for a single person to handle and position
safely. Also, whilst the stone pieces on the surface of an individual block can be randomly
spaced to provide a realistic stone built efiect, the rectangular outline of the individual
blocks can sometimes be seen to disrupt the random appearance on a completed surface
comprising a number of the blocks.
An object of the present invention is to improve upon the decorative building
blocks described above.
In a first aspect the present invention is a decorative building block comprising;
a supportive load bearing body having applied to at least one surface a decorative
arrangement of mineral pieces wherein the load bearing body comprises a mixture of a
cement and lightweight aggregates.
The block according to the invention is significantly lighter in weight than existing
decorative blocks. By adding various proportions of lightweight aggregate to the mould
mix for the load bearing body the resulting block can be reduced sufficiently in weight that
it compensates for at least some of the excess weight due to the stone facing and becomes
manageable by one person.
For the purposes of the invention a “lightweight aggregate” should be interpreted
as meaning an aggregate having a density significantly lower than a standard build spec
concrete. Any suitable lightweight aggregate may be used either alone or in combination
with other known lightweight aggregates. Such aggregates are well known and in
common use in other applications and include sintered PFA; pumice; expanded mica;
recycled furnace materials, refractory materials, spent solid fuels and the like. Preferably
the lightweight aggregate portion will comprise a significant proportion of both coarse and
tine aggregates, to provide maximum weight reduction.
In order to meet the requirements of British Standards and any other relevant
regulations load-bearing blocks must be able to withstand any specified loads. The term
“load-bearing body” as used herein should be interpreted accordingly. Varying
proportions of cement and aggregates (both lighter and normal weight) may be used in the
body, provided that set moulding meets the specified strength criteria. Typically, in order
to be considered load bearing a block should be able to withstand a load of at least about
7N/minz.
In preparing thebacking concrete material for moulding, the cement and aggregate
mix is mixed with water. The particles of lightweight aggregate are highly absorbent and
take up much of the water in the mix. On curing, the excess absorbed water evaporates
from the aggregate leaving air pockets and thus fiirther reducing the overall density of the
block.
Additives may optionally be added to the concrete backing mix to further reduce
the weight. A preferred additive is an air entrainment agent. These agents create air
bubbles in the moulded block and the density of the structure is further reduced. The
concrete mix is designed to ensure that there is no detriment to the load bearing capability
of the structure.
Water reducing agents can also be added to the concrete backing mix. Such an
agent will reduce the water content for any workability and can facilitate mixing and
pouring of the mix material into the mould and improve strengths.
The decorative arrangement of mineral pieces may comprise pieces of flint,
sandstone, limestone, pebbles, cobbles or any similar attractive naturally occurring or
other artificial materials such as bottles etc., stone or mineral. The pieces may be whole,
particularly in the case of cobbles and pebbles, or cut and may be dressed or undressed.
Preferably, the proportions by weight of cement to lightweight aggregate are
between about 1:7 and about 1:2, most preferably about 1:3 to 1:4. However, these will
vary dependent on the type/ s of aggregate used.
In a second aspect, the invention is a decorative building block comprising; a
supportive load bearing body having applied to at least one surface a decorative
arrangement of mineral pieces wherein the block is provided-with a peripheral lip on the
at least one surface providing a greater surface area in which to set the mineral pieces.
The lip on the mould allows a decorative surface which extends slightly beyond
the perimeter of the load bearing body, this enables some of the set decorative mineral
pieces to be positioned to overhang the edge of the load bearing block. When two or
more blocks are adjoined, say in building a wall, the overhanging mineral pieces can be
aligned to fit into gaps on adjacent blocks. This results in a less apparent demarcation
between blocks and a more random overall pattern of pieces on the completed wall
surface.
In order to achieve a block according to this second aspect, the mould for the load
bearing body is provided with a peripheral lip sufficiently deep to receive pieces of mineral
to be used in the decorative facing. The lip will typically extend up to about 3mm beyond
the edge of the load-bearing block but can extend up to 5mm. This has been found to be
sufficiently large to provide the desired eifect without interfering with the laying of the
blocks.
Whilst it is preferred that this aspect be used in conjunction with lightweight
blocks according to the first aspect, it will occur to the skilled addressee that this aspect
may be equally used in the improvement of prior art facing blocks.
A fiirther improvement is provided in the form of a frog, which is incorporated
around the periphery of the block between the outer facing decorative surface and the
inner-facing surface of the block. The frog is provided in the form of a groove of any
suitable cross section such as a V or rectangle or square, preferably the cross-section is
arcuate, most preferable semi-circular. Whilst the frog may be incorporated at any
position between the decorative surface and the inner surface, it is preferably positioned
about midway between the two surfaces. The width and depth of the frog are not critical
but they are preferably of the order of a few centimetres for the width and a few
millimetres for the depth. The frog provides a keying surface for the mortar when the
blocks are laid as the blocks have to be laid with reduced bed and perpendicularjoints of
ideally 5mm but between 2mm and 8mm (normally 10mm) to achieve the best results.
Again, whilst it is preferred that this aspect be used in conjunction with the novel
blocks according to other aspects of the invention, it will occur to the skilled addressee
that this feature may be equally used in the improvement of prior art facing blocks.
Conveniently, by using a suitably adapted mould, the lip and frog can be
incorporated when the block is moulded. Most conveniently, the blocks can be moulded
in a “rubber” or similar flexible mould, which can be peeled away from the set block
without risk of damage.
For the purposes of clarification and exemplification, an embodiment of the
invention will now be described with reference to the following Figures. Other
embodiments will no doubt occur to the skilled addressee without departing from the true
scope of the invention as defined by the appended claims.
Figure 1 shows a block according to the present invention.
Figure 2 shows pairs of blocks according the present invention before and after
alignment to form a single wall surface.
As can be seen from Figure I a block according to the present invention comprises
a load bearing concrete or mortar body 1 onto the surface of which is provided a
decorative facing 2 comprising a number of flint or similar mineral pieces 3 set into
concrete. The mould has a peripheral lip extending from the upper surface into which
pieces of flint or similar mineral pieces 3 can extend. Around the periphery of the load-
bearing block is a frog 5 of semi—circular or other cross-section.
Figure 2 shows the top face of two facing blocks according to the present
invention. It can be seen that the hand set mineral pieces provide a slightly irregular
shaped periphery to the top surface of the facing block. Blocks can be then matched such
that protrusions from one block can be aligned with indentations on adjacent blocks. As
can be seen from Figure 2b this results in a far more random surface pattern when the
blocks are laid together.
An example will now be given of one suitable composition for the manufacture of
a lightweight-facing block in accordance with the invention.
In one embodiment the composition used to mould the load—bearing body
comprises 3. Rugby Class 42.5N Portland cement as sold by Rugby Cement. The
aggregate used is an all-in block mix provided by Lytag, the mix has a high proportion of
fine aggregate particles. A water-reducing admixture and an air entrainment agent are
also added. The relative proportions in kg/m3 are illustrated in Table 1. The composition
is mixed and fed into a mould using conventional techniques.
Blocks made using the above-described composition were tested and the following
results achieved.
The Composition.
Used a lightweight “block mix” with a high proportion of fines appropriate to the
materials used and the backing concrete to be produced. The mix gave satisfactory fresh
concrete properties.
The mix details (rounded to the nearest 5 kg/m3) are summarised below: -
TABLE 1
M.ix Constituents -
360
1145
.6
0.36
TE STING
Two 100mm-cube specimens were produced from the mix to enable estimation of mix
density; weight loss with time and compressive strength.
The balance of the mix was used to produce blocks for determination of weight and
compressive strength. Some cobble-faced blocks were also produced as well as the flint
faced blocks to provide information on the bond of the backing concretes to the smoother
faced materials.
Concrete Density
The density results and the density reductions for the mixes with age were as follows: -
TABLE 2
Age Days Density/Reduction in Density with
Age — kg/m’
- As Shipped 1710
/80
/ 145
The lightweight aggregate is absorbent and takes up a significant amount of the mix water.
As the concrete cures and then dries out, a significant reduction in density occurs, as this
absorbed water evaporates. This process has the potential to provide some usefiil
additional curing for these “dry cured” blocks.
The test cubes were stored in air in the laboratory to simulate the treatment of the blocks
on site. After 28 days the mix density had reduced by l45kg/in’ to l565kg/m3. The full
density advantage of the lightweight thus takes some time to develop.
Compressive Strength
The specimens were stored in their moulds under ambient site conditions until stripped
after a weekend at about 64 hours age. They were then stored in air in the laboratory (at
°C) until test. This curing regime was expected to simulate the air curing that would
be received at the works.
The compressive strengths of the cube specimens were tested at 7 and 28 days. The
results are based on single cubes. The cube strength results are summarised below: -
TABLE 3
Age - Days 100m Cube Strength — N/mm‘ J
}7 25.4 J
r23 30.1 J
The blocks were weighed after stripping and four blocks were selected for strength
testing from each mix. These were chosen as the four nearest to the normative weight
(the highest and lowest weight blocks being discarded for strength testing).
TABLE 4
lAge - Days Block Strength - N/mm’
(7 10.6
lzs 13.4 4»
Weight Saving
The weights of the original blocks averaged about 21kg. A significant part of this is
the weight of the flint. Initial calculations suggested that the weight of flint be about
6.5kg.
The blocks were weighed on stripping and the average for these lightweight flint blocks
was as follows:
TABLE 5
Average Block Weights - kg
(All Block Weights include about 6.5kg
weight of flint facings)
On Stripping (corrected value) 18.9
Days 18
Days 17.5
The preliminary tests have shown that a lower density backing concrete can be produced
which can reduce total block Weight by about 35 kilograms. The preferred mix uses a
lightweight all-in aggregate.
Air entrainment was introduced into the mortar by use of an admixture. This was
expected to have several advantages: - It would provide some further weight reduction;
it would reduce bleeding which would hopefully increase bond; it would provide some
durability advantages.
In view of the high strengths of the original blocks, the cement contents were reduced to
produce some saving in cost. It is possible that some fiirther cement content reduction
could be made.
A water reducing plasticiser was also used to offset some of the strength reduction effects
of: - The lowered cement content; the lower strength lightweight aggregate; the air
content provided by the air entrainment.
The test results for this embodiment of the invention may be summarised as follows‘
TABLE 6
Results at 28 Days Mix
Cube Strength (N/mmz) 30
Block Strength (N/mmz) 18.5
Block Wt (Kg) 17.5
Weight Saving (Kg) 3 .5
Claims (1)
- CLAIMS A decorative building block comprising: a load-bearing body having applied to at least one surface a decorative arrangement of mineral pieces wherein the load bearing body comprises a mixture of cement and lightweight aggregates. A decorative building block as claimed in claim 1 wherein the load-bearing body is able to withstand loads of at least 7 N/mm? A decorative building block as claimed in claim 1 or claim 2 wherein the mixture of a cement and lightweight aggregates further includes an air entrainment admixture. A decorative building block as claimed in any preceding claim wherein the mixture of a cement and lightweight aggregates fiirther includes a water reducing agent. A decorative building block as claimed in any preceding claim wherein the cement and aggregates are provided in proportions by Weight of between about 1:7 and about 1:2. A decorative building block as claimed in claim 3 wherein the cement and aggregates are provided in proportions by weight of between about 1:3 and 1:4. A decorative building block as claimed in any preceding claim wherein the mould is provided with a peripheral lip such that the decorated surface can have a variably greater surface area. 10w ll. A decorative building block as claimed in any preceding claim wherein the block has a frog around its periphery. A decorative building block as claimed in claim 3 wherein the frog is arcuate in cross-section. A decorative building block as claimed in claim 8 or claim 9 wherein the frog is positioned about midway between the upper and lower face of the block. A decorative building block substantially as described herein and with reference to the
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBUNITEDKINGDOM04/12/19999928583.5 | |||
GBGB9928583.5A GB9928583D0 (en) | 1999-12-04 | 1999-12-04 | Improvements relating to decorative building blocks |
Publications (2)
Publication Number | Publication Date |
---|---|
IE20000147A1 IE20000147A1 (en) | 2001-07-11 |
IE84379B1 true IE84379B1 (en) | 2006-10-18 |
Family
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