Civil Engineering Materials
by
Dr. Prashanth J.
Civil Engineering Department
National Institute of Technology Silchar
Chapter 9
STONES as
BUILDING MATERIAL
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Building Stones
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Stones - Introduction
• They occur naturally and
need not be
manufactured.
• Old roads with heavy
traffic were also paved
with stones,
• Beautiful monuments were
also built with stones.
• Stones were also used for
ornamental works.
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• Stones are more permanent than
any other natural materials like
wood.
• Stones are used for heavy
engineering constructions like
bridge piers, harbour walls, sea
side walls, and also for facing
work, tall buildings, foundations of
buildings (which are liable to be
flooded – stoned instead of brick
work)
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Civil Engineering Uses
Construction of residential and public buildings
Construction of dams, weirs, harbors, bridge
abutments, etc.
Face work of structures for appearance and
ornamental value
Road metal and railway ballast
Aggregate for concrete
Stone dust as substitute for sand
Thin slabs for roofing, flooring and pavements
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Limestone for manufacture of lime, cement, etc.
Building Stone
Stone: A construction material derived from rocks in
the earth’s crust and mixture of two or more
minerals.
Mineral: is a substance which is formed by the
natural inorganic process and possesses a definite
chemical composition and molecular structure.
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Classification of Rocks
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Classification of Rocks
Rocks
Geological Physical Chemical Practical
Granite,
Igneous Stratified Argillaceous
Basalts
Sedimentary Un-Stratified Siliceous Marble
Limestone,
Metamorphic Foliated Calcareous Sandstone,
Slate
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Geological classification
Igneous rocks (primary, un-
stratified, eruptive) – cooled down
molten volcanic lava (magma).
Basalts and granites.
Sedimentary rocks (aqueous,
stratified) – gradually deposited
disintegrated rocks.
Sand stones and lime stones.
Metamorphic rocks – transformed
due to great heat and pressure.
Granite to gneiss, lime stone to
marble, shale to slate
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Physical classification
Stratified
Stratified Rocks
Show distinct layers along which the rock
can be split due to the deposition of
organic and inorganic particles.
Eg. Sandstone, limestone, shale, slate,
marble, etc Un-stratified
Un-stratified rocks
Do not show any stratification and cannot be
easily split into thin layers.
Eg. Granite, basalt, trap
Foliated Rocks
Have a tendency to split up only in a definite
direction.
Eg. Gneiss result of heat and pressure
Most of the metamorphic rocks except marble
and quartzite
Foliated
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Chemical Classification
Siliceous rocks – containing silica
SiO2 (sand) and silicates.
Granite, basalt, trap, quartzite,
gneiss, syenite, etc.
Argillaceous rocks – containing
clay or alumina Al2O3.
Slate, laterite, etc.
Calcareous rocks – containing
calcium carbonate or lime.
Limestone, marble, dolomite, etc.
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Classification of Rocks
Practical Classification
Granites
Basalts
Marbles
Sandstones
Slates
Etc., etc.
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Important types of
building stones
GRANITE – Igneous rock
Composition –Quartz, feldspar and mica.
Characteristics
• Hard, strong and durable unstartified stone.
• It is crystalline and fine to coarse grained.
• G=2.63 - 2.75 and absorption <1 %
• Significantly strong and durable
• Compressive strength 90-150 MN/m2
• The hardest and most durable granite contains a greater proportion of
quartz and smaller proportion of feldspar and mica.
• Feldspar renders the stone light in colour.
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Uses
• Construction of sea wall, light houses, bridge piers
• Suitable for ornamental columns, plinth etc.
• Large pieces are used as building blocks, the smaller as road
metals or railway ballast and chippings for manufacture of
concrete or artificial stone.
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Polished Surface
Rough Texture
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BASALT- igneous rock
Composition – Feldspar, augite, alumina, silica etc.
Characteristics
Hard, compact and durable unstartified stone.
Heavier than granite.
G=2.6 - 3.0 and absorption <1 %
Compressive strength 150-200 MN/m2
Cannot be generally obtained in large blocks.
It has grey, dark, green, blue, black, red and yellow colours.
Uses
Construction of roads/railway ballast.
Building construction.
Used as aggregate in concrete.
Red and yellow varieties used in ornamental work.
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LIMESTONE-sedimentary rock
Composition – calcareous, CaCO3, MgCO3, alumina,
silica etc.
Characteristics
It is durable and can be sawn, plane, lathed and carved easily,
effectively and economically.
G=2.6
Compressive strength 30 to 40 MN/m2
Available in brown, yellow and dark grey colours.
Uses
Used as road metal when granite and basalt not available.
Building construction (stone masonry).
Used as in large quantities in blast furnaces, bleaching and
tanning.
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Limestone
with Granite
Limestone and Slate
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SANDSTONE-sedimentary rock
Composition – siliceous variety, contains sand or quartz cemented
by CaCO3, mica, aluminum, oxides of iron or by mixture of these
materials etc.
Characteristics
Strong and durable fine grained stone.
G=2.25
Compressive strength 35 to 40 MN/m2.
It splits easily into large slabs along the bedding.
Available in brown, white, grey, pink colours.
Durability is a function of the cementing agent.
Uses
The fine grained and compact variety is suitable for ashlar work,
mouldings, carving etc.
The rough and coarse Used as in large grained stone is employed
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for rubble work.
Sandstone Columns
Old Red Sandstone
Basalt and Sandstone
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MARBLE-metamorphic rock
Composition – calcareous variety. It is changed from
limestone. It is crystalline hard compact stone having CaCO3,
as the main constituent.
Characteristics
It is hard (Mohs scale 3-4) and compact.
Takes fine polish.
G=2.72
Compressive strength 80 to 90 MN/m2.
Available in yellow, white, grey, green, red, blue and black
colour.
Uses
It is used for carving and decoration work.
It is also used for steps, wall linings, electrical switch boards, table
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slabs and columns.
Marble - Flooring
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Marble - Exterior Application
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Moh’s Hardness Scale
1 Talc, scratched easily by thumb nail
2 Gypsum, scratched by thumb nail
3 Calcite, scratched not by thumb nail but by knife
4 Fluorite, cut by knife with difficulty
5 Apatite, cut by knife with difficulty more than 4
6 Orthoclase, cut by knife with great difficulty
7 Quartz, not scratched by steel, scratches glass
8 Topaz
9 Sapphire
10 Diamond 27
SLATE-metamorphic rock
Composition –Argillaceous variety. It is changed from shale. It is
composed of alumina mixed with sand or carbonate of lime.
Characteristics
A good slate is hard, tough and durable fine grained stone.
It can be split into thin sheets .
G=2.8
Compressive strength 60 to 70 MN/m2.
It is non-absorbent.
When struck with a light hammer, it produces sharp metallic rings.
Uses
Most suitable for roof coverings, floorings, damp proofing and
partitions.
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Slate Roofing
Slate Flooring
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Characteristics of Good
Building Stones
Appearance & color – uniform color, lighter shades preferred,
free from clay holes, bands or spots.
Structure – Not dull in appearance, crystalline homogenous close
grained is good, stratification should not be visible, fine grained
for carving.
Crushing strength: For a good building stone, the crushing
strength should be greater than l00 MN/m2.
Specific gravity: For a good building stone the specific gravity
should be greater than 2.7 or so.
Hardness– resistance to abrasion, friction and wear. Hardness
scale 1 to 10.
Toughness – Withstand impact, vibrations, moving loads.
Dressing – uniform texture and softness for fine surface finish. 31
Characteristics of Good
Building Stones
Porosity and Absorption – For building purposes, the better
stones are those which are less porous because they will
absorb less moisture. Porous stones damaged easily.
Seasoning – All the stones contain some moisture which is
known as quarry sap. The period 3-6 months are enough
for seasoning.
Weathering – resistance to action of weather.
Resistance to fire – A good building stone should be fire
resistant. Some stones such as basalt and trap resist fire
very well but some varieties of igneous and metamorphic
stones are very weak against fire
Durability – Durability is the power of stone to resist
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atmospheric and other external effects.
Selection of Stones
Heavy engineering works bridges, piers, abutments, break
waters, docks, light houses – granite (biotite, hornblende,
tourmaline)
Buildings facing the sea – granite, fine grained sandstone
Buildings in industrial area – granite, compact sandstone
Arches – fine grained sandstone
Building face work – marble, close grained sandstone
Fire resisting structure – compact sandstone
Road metal and aggregate for concrete – granite, basalt,
quartzite
Railway ballast – coarse grained sandstone, quartzite
Electrical switch board – slate, marble 33
Artificial Stone
Definition - Building material made with cement,
sand and natural aggregates of crushed stone
for use in place of natural stone
Properties
Made with white cement, sand and natural
aggregates of crushed stone
Molded into most intricate forms
Cast into any size
Desired coloring may be achieved
Desired finish may be achieved 34
Terrazzo
Terrazzo is a man-made conglomerate. A conglomerate is a group
of rocks which are cemented together usually using limestone.
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Mosaic
Mosaic is the art of covering and decorating a surface or item with small
mosaic tiles.
Mosaic tiles or tesserae can be made from any hard material – glass,
mirror, tiles, pebbles, shells, ceramic shards and more
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Any Questions ???
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