STONES
Introduction
Stones are known to geologists as rocks, is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general, rocks are of three types, namely igneous, sedimentary, and metamorphic, and they are useful in building:
i) blocks in masonry walls
ii) slabs in floorings
iii) roofing slates
iv) aggregates in concrete
v) terrazzo in floor finishes
vi) rock wool for insulation, etc...
Stones can be either Artificial or Natural
Stone masonry is similar in concept to brick/block masonry. Both involve the stacking of preformed units and bonded in mortar.
Stones are known to geologists as rocks, is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general, rocks are of three types, namely igneous, sedimentary, and metamorphic, and they are useful in building:
i) blocks in masonry walls
ii) slabs in floorings
iii) roofing slates
iv) aggregates in concrete
v) terrazzo in floor finishes
vi) rock wool for insulation, etc...
Stones can be either Artificial or Natural
Stone masonry is similar in concept to brick/block masonry. Both involve the stacking of preformed units and bonded in mortar.
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Construction
Material That build GREAT WALL OF CHINA
Before the use of
bricks, the Great Wall was mainly built from earth, stones and wood. Due to the
large quantity of materials required to construct the Great Wall, the builders
always tried to use local sources.No fortresses were constructed along the wall,
nor bricks used in the construction of gates at the passes. Some of the walls
were even made only from piles of crude stones.
In early
In early
·
In mountain, stones of
the mountain were exploited and used.
·
In the plains, earth
was rammed into solid blocks to be used in construction.
·
In the desert, even the
sanded reeds and juniper tamarisks were used to build the Great Wall.
In Qin Dynasty
(221BC-206BC) or earlier
·
the Great Wall was
basically built by stamping earth because of the weapons like swords and spears
at a low technology.
·
Neither fortresses were
constructed along the wall, nor bricks were used in the construction of gates
at the passes.
In Han Dynasty
(202BC-220AD)
·
basically earth or
crude stones were still popular is used for the construction
·
the appearance of large
brick and lime workshops, some parts were also built with these new materials.
In Ming Dynasty
(1368-1644)
·
the wall was built with
a tamped-earth interior between kiln-fired bricks and stone slabs forming the
outer layers.
·
Bricks were used in a
lot of areas during the Ming Dynasty, as well as materials such as tiles and
lime.
·
Some of the wall is
build by mixed lime and sticky rice as a mortar filled between the bricks.
Below is some example of Brick and Stone that used to build Great Wall of China
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Artificial Stone
Sometimes called engineered stone. They are made from
crushed natural stones bonded together using Portland cement with very low
water/cement ratio of less than 0.32. The cement (binding particles) can be
colored by adding inorganic dyes (pigments) match the colours of the stones.
The
natural stones used in the manufacture of artificial stones can be either:
1. Calcareous stone materials; such as marble, limestone or dolomite.
2. Siliceous stone materials; such as granite, quartzite, sand, porphyry, etc...
Aesthetic appearances of artificial stones vary according to the nature, colour and quality of the aggregate used as well as the bonding (cement) paste. It is possible to manufacture products having special made-to-measure aesthetic visuals to meet the demands of architects and building owners.
Versatility is one of the major features of artificial stones. The wide dimensional range and aesthetic appearance make them ideal for;
· outdoor and indoor floorings
· outside claddings
· internal facings
· steps
· raised floor systems
· window sills, etc...
1. Calcareous stone materials; such as marble, limestone or dolomite.
2. Siliceous stone materials; such as granite, quartzite, sand, porphyry, etc...
Aesthetic appearances of artificial stones vary according to the nature, colour and quality of the aggregate used as well as the bonding (cement) paste. It is possible to manufacture products having special made-to-measure aesthetic visuals to meet the demands of architects and building owners.
Versatility is one of the major features of artificial stones. The wide dimensional range and aesthetic appearance make them ideal for;
· outdoor and indoor floorings
· outside claddings
· internal facings
· steps
· raised floor systems
· window sills, etc...
 |
| Mould for stones |
Manufacturing Process
A mixture of the raw materials; crushed stones and the
bonding agent (cement or sometimes polymers), is compacted by vibration under
vacuum to produce:
1. Slabs (tiles),
Where thin monolayer tiles of the required sizes are produced.
2. Large-size blocks.
These blocks are then sawn into slabs to be transformed into finished products with the required sizes.
1. Slabs (tiles),
Where thin monolayer tiles of the required sizes are produced.
2. Large-size blocks.
These blocks are then sawn into slabs to be transformed into finished products with the required sizes.
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Natural Stone
Stones used in building are obtained by taking rocks from the earth and
cutting them to the sizes and shapes for construction. 3 types of rocks are
quarried to produce building stone:
· Igneous rock – Hard and non-porous rock formed from the slow or quick cooling of molten magma. – granite, basalt
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Appearance
Igneous
rocks make useful road building materials. When sheets of igneous rock are cut
and polished, they are used inside buildings such as banks and offices, and are
also used as gravestones. There are different types of igneous rock, therefore
each type has its own uses, such as: Granite: Used for long lasting monuments,
for trim and decoration on buildings. Pumice: Because they are so light, it is
used quite often as a decorative landscape stone. If grounded to a powder, it
is used as an abrasive in polish compounds and in Lava soap. Crystalline
Igneous rocks can be used for jewelery and other similar things. Countertops
and building stone. Lava soap, building materials, landscaping .
Granite is of main interest in building construction.
Limestone may be composed of
either calcium carbonate or of a mixture of calcium and magnesium carbonates.
Colours range from almost white through gray and buff to iron oxide red.
Sandstones consists of
fine or coarse particles of quartz with particles of feldspar or mica, bound
together by a natural cement. The natural cement is the chief factor in
deciding the strength, durability and colour of the sandstone.
Sandstones are classified according to the type of natural cement:
1.Siliceous sandstones – cemented by compounds of silicate. They are extremely acid resistant and durable, but difficult to work with. Silica tends to give a light gray colour.
2. Calcareous sandstonesare cemented with calcite crystals of calcium carbonate, which in their pure form are white. The stone is more easily worked than siliceous sandstone but is less durable and should be used externally only in rural areas.
3.Dolomite or magnesium sandstones are bound with calcium carbonate and magnesium carbonate. They are of white-buff colour.
4.Ferruginous sandstones contain oxides of iron, giving brown, red and yellow colours. They weather well.
Sandstones are used mostly for pavings, steps and thresholds.
Slates
· Igneous rock – Hard and non-porous rock formed from the slow or quick cooling of molten magma. – granite, basalt
  |
| Granite |
This
is example of house build by stone ^^
General
Properties of Natural Stones
Different types of rock exhibit properties which can
vary from one to the other
Appearance
The fossils, veins, grains and other features make
natural stones, when polished, exciting and interesting. They can have very
interesting textures or patterns.
Natural stones usually retain their good appearance
inside buildings. Externally if left to weather naturally, limestones improve
in appearance and slate does sometimes.
Durability
Natural stones are generally extremely durable but
deterioration may result from wrong choice of stone being exposed to the
weather elements. Other causes of deterioration include faulty design and
workmanship, atmospheric pollution, soluble salt action, frost, wetting and
drying, solution, rusting of ferrous metals and vegetation growth.
Atmospheric pollution mainly from sulphur
compounds.Sulphurdioxide formed by burning coal and oil, when dissolved in
water, produce sulphuric acid. This reacts with carbonates in limestone,
dolomite, calcareous sandstones and mortars. The product of this reaction, if
not freely washed away by rain, will form a hard glassy skin which tends to
break away and forming blisters on the surface of the stones.
Soluble salts present in the
stones, exert expansive force when they crystallize andare the chief cause of
progressive decay.
Thermal
movement. The differences between thermal movements of
reinforced concrete (coefficient of thermal expansion 10-14 x 10-6 K-1)
and some stone claddings (particularly marble with coefficient of thermal
expansion of 2.4-9 x 10-6 K-1) fixed with ‘tight’ joints
have caused stresses resulting in failures in fixings. Compressible
movementjoints should be provided to accommodate differential thermal movements
Igneous
Stones
Properties
of Igneous Rocks:
-Magmatic
consolidation
-
Both Crystalline and Non-Crystalline
- Non-porous
- Poorly eroded
- Content of Silica
- No Fossils
- Non-porous
- Poorly eroded
- Content of Silica
- No Fossils
Granites
It
is a mosaic of mineral crystals, mostly of feldspar, mica and quartz. It can be
obtained in a range of colours like gray, black, pink, red, brown and green.
Properties of granite:
- high compressive strength up to 335 N/mm2,
- nonporous,
- hard and durable, being able to withstand hard
knocks and abrasion,
- resistant to ordinary chemicals,
- high density of between 2460-3200kg/m2,
- impermeable making it a very good material for
damp-proof courses or bases in contact with the ground.
Because granites are extremely dense and hard, they
can be costly to quarry, cut and surface. They can be polished mechanically to
a mirror-like finish. Granite can be fine grained, medium grained and coarse
grained.
Applications- granite can be cut and
polished to be used as external wall claddings, floorings, internal wall tiles,
counter tops and others. They made very attractive but expensive finishes.
Sedimentary
Stones
Examples
of sedimentary stones – limestone, dolomite and sandstone.
These are formed from either;
1. Particles of older rocks broken down by the action of water, wind or ice, or
2. Accumulations of organic materials; skeletons or shells of marine organisms.
These are formed from either;
1. Particles of older rocks broken down by the action of water, wind or ice, or
2. Accumulations of organic materials; skeletons or shells of marine organisms.
The above particles are cemented together by minerals
originally carried in solutions in water, and consolidated by super-imposed
deposits.
Sediments of the particles carried by water and wind
lie horizontally in layers which give the rocks the natural grains.
Limestone may be composed of
either calcium carbonate or of a mixture of calcium and magnesium carbonates.
Colours range from almost white through gray and buff to iron oxide red.
Properties
1. Limestone is porous.
2. Limestone vary widely in hardness,
3. Limestones are soluble in water containing carbon dioxide –self-cleansing where they are washed by rain water.
4. Limestones are attacked by acids. Sulphurous matter in soots reacts with the limestone forming a glassy skin of either calcium or magnesium sulphates which acts as binder for further soot and dirt and lead to rapid decay of the softer limestones.
2. Limestone vary widely in hardness,
3. Limestones are soluble in water containing carbon dioxide –self-cleansing where they are washed by rain water.
4. Limestones are attacked by acids. Sulphurous matter in soots reacts with the limestone forming a glassy skin of either calcium or magnesium sulphates which acts as binder for further soot and dirt and lead to rapid decay of the softer limestones.
Sandstone
Sandstones are classified according to the type of natural cement:
1.Siliceous sandstones – cemented by compounds of silicate. They are extremely acid resistant and durable, but difficult to work with. Silica tends to give a light gray colour.
2. Calcareous sandstonesare cemented with calcite crystals of calcium carbonate, which in their pure form are white. The stone is more easily worked than siliceous sandstone but is less durable and should be used externally only in rural areas.
3.Dolomite or magnesium sandstones are bound with calcium carbonate and magnesium carbonate. They are of white-buff colour.
4.Ferruginous sandstones contain oxides of iron, giving brown, red and yellow colours. They weather well.
Sandstones are used mostly for pavings, steps and thresholds.
Metamorphic
Stones
These
are stones which had been subjected to immense heat and pressure, causing
structural change to the original stones.
Original
material Metamorphic stone
Clay Slate
Limestone Marble
Sandstone Quartzite
Slates
Slates
are formed by immense earth pressure acting upon clays. It is a dense hard
stone with closely spaced planes of cleavage, along which it is easily split
into sheets. This makes them useful for paving stones, roof shingles and thin
wall facings.
Properties
- good slates are
durable,
- good slates are acid and alkali resistant. Poor slates, however, can decay quickly especially in damp conditions. Sulphide of iron present in some slates may form hydrated iron oxide and sulphuric acid, which can attack any calcium carbonate present in the slate,
- strong in tension and compression when compared with other stones,
- very hard and denser than granite,
- has negligible moisture absorption and impervious,
- no moisture movement,
- a good electrical insulator,
- interesting appearance with textures ranging from silky to very rough. Colours include gray, black, red, blue, purple, green and brown.
Marbles
Marble is a recrystallised form of limestone. Marbles which have a consistent pattern throughout the thickness of a block lend themselves to ‘matching’ of adjacent slabs to form symmetrical patterns.
Pure marble is generally very finely crystallized. It is white, but coloured minerals often occur as a general coloration, as veins or other markings, which make marble interesting and beautiful. Malaysiaproduces marble they are limited in colour; mostly white, pink and gray.
Most of the more expensive marbles used are imported from countries like Italy,China, Turkey and others.
Properties
- varying colours and veins,
- very hard, dense and resistant to abrasion,
- excellent self-polish which greatly enhance its appearance,
- susceptible to acid attacks, thus polished surface is not retained for long if used externally in a polluted atmosphere,
- sugaring can occur on exposed surfaces and highly coloured marbles tend to fade,
- impervious, but discoloration can result in damp conditions
- good slates are acid and alkali resistant. Poor slates, however, can decay quickly especially in damp conditions. Sulphide of iron present in some slates may form hydrated iron oxide and sulphuric acid, which can attack any calcium carbonate present in the slate,
- strong in tension and compression when compared with other stones,
- very hard and denser than granite,
- has negligible moisture absorption and impervious,
- no moisture movement,
- a good electrical insulator,
- interesting appearance with textures ranging from silky to very rough. Colours include gray, black, red, blue, purple, green and brown.
Marbles
Marble is a recrystallised form of limestone. Marbles which have a consistent pattern throughout the thickness of a block lend themselves to ‘matching’ of adjacent slabs to form symmetrical patterns.
Pure marble is generally very finely crystallized. It is white, but coloured minerals often occur as a general coloration, as veins or other markings, which make marble interesting and beautiful. Malaysiaproduces marble they are limited in colour; mostly white, pink and gray.
Most of the more expensive marbles used are imported from countries like Italy,China, Turkey and others.
Properties
- varying colours and veins,
- very hard, dense and resistant to abrasion,
- excellent self-polish which greatly enhance its appearance,
- susceptible to acid attacks, thus polished surface is not retained for long if used externally in a polluted atmosphere,
- sugaring can occur on exposed surfaces and highly coloured marbles tend to fade,
- impervious, but discoloration can result in damp conditions
The Different Forms in Which Stones are Used
The construction industry uses stones in the following forms:
· Fieldstone – rough stones obtained from river beds and fields.
· Rubble – irregular quarried fragments that have at least one good face.
· Dimension stone- quarried and cut into rectangle form.
· Cut stone- quarried and cut into large slabs.
· Ashlar – small rectangular blocks.
· Flagstone – thin slabs of stone; either regular or irregular shape, used for flooring and paving.
· Crushed stone – useful in site work as freely draining fill material, pavings, surfacing materials and aggregates.
The construction industry uses stones in the following forms:
· Fieldstone – rough stones obtained from river beds and fields.
· Rubble – irregular quarried fragments that have at least one good face.
· Dimension stone- quarried and cut into rectangle form.
· Cut stone- quarried and cut into large slabs.
· Ashlar – small rectangular blocks.
· Flagstone – thin slabs of stone; either regular or irregular shape, used for flooring and paving.
· Crushed stone – useful in site work as freely draining fill material, pavings, surfacing materials and aggregates.
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