Building stone

The earth’s crust is composed of rocks. Rock
is a mineral mass of a more or less uniform
composition. It may consist of a single mineral
(monomineralic) or of several minerals
(polymineralic).
 Monomineralic rocks are quartz sand, pure
gypsum, and magnesite
 Polymineralic rocks are granite, basalt, and
porphyries

 Natural rock materials are widely used for
building purpose owing to their universal
occurrence and physical and mechanical
properties.
 Rocks are the main source of material for the
manufacture of mineral binding materials, such
as gypsum, lime, cement and of artificial rock
materials, eg.,brick, glass, items for concrete
and mortar.

 The origin and conditions of rock formation
predetermine their chemical and mineralogical
composition, crystalline structure and texture.
 The three major classification are based on the
following aspects :
(1) Geological or genetic classification
(2) Physical classification
(3) Chemical classification

 According to the geological classification, rocks
are subdivided into three large groups, igneous
rocks, sedimentary rocks, and metamorphic
rocks.
(1) Igneous rocks :
Cooling and hardening of
molten magma result in the formation of igneous
rocks. Depending on the rate of cooling the sizes
of crystals are formed.

 Granite, syenites, diorites and gabbros have
large crystals, while basalts, rhyolites and
andesites have small crystals.
 Igneous rocks are generally very hard.

(2) Sedimentary rocks :
Transportation agents like
wind, water and ice may move the loose
weathered rock material and deposite them in the
form of layers called sediments. Such sediments
when subjected to heavy pressure undergo
compaction and cementation, resulting in the
Sedimentary rocks. Limestone, dolomite, shale,
sandstone, etc., are sedimentary rocks

(3) Metamorphic rocks :
Sedimentary rocks and to
some extent igneous rocks when subjected to
changes brought about by the combination of
heat, pressure and plastic flow ( called
metamorphism) undergo changes in the structure,
Texture and mineral composition, and this results
in the formation of metamorphic rocks. Gneiss,
schist, slate, marble, etc. are metamorphic rocks.

 The basis for such a classification is the physical
properties of rocks, the manner and arrangement
of different particles and mass forming a stone.
They classified as follows:
(1) Foliated rocks
(2) stratified rocks
(3) Unstratified rocks
 Foliated rocks :
These rocks shows definite paeallel arrangement of
minerals showing a tendency to split in a specific
direction.
Examples : metamorphic rock like gneiss, schist

 Stratified rocks :
Stratified structure is formed due to the splitting
of parallel layers of sedimentary rocks. They
exhibit distinct layers which can be separated. The
plane of separation is called as a cleavage plane.
Examples : Limestone, slate, and sandstone
 Unstratified rocks :
They are granular or crystalline structure and
become solid and cooling. They do not show any
sign of strata.
Examples : igneous rocks like granite, basalt, etc.

 The presence of chemical constituents in the rocks
is the basis for their type of classification.
they are as follows :
(1) Argillaceous rocks
(2) Siliceous rocks
(3) Calcareous rocks
 Argillaceous rocks :
In these rocks clay and alumina is the main
constituents.
Examples of the aegillaceous rocks are slate,
laterite, etc.

 Siliceous rocks:
In these silica is the main constituent. The presence of
the silica in the free state is called sand, and in the
combined state is s silicate. Rocks containing silica in
the free state are harder, and those found in the
combined form are likely to be disintegrated.
Examples of the silicate rocks are sandstone,
quartzite, etc.
 Calcareous rocks
Calcium carbonate or lime is the main constituents in
these rocks. They are readily acted upon by dilute
HCL
Examples are limestone, marble, etc.

 Different civil engineering construction use
stone. It is necessary to find their suitability
under different condition. The following
properties need to be examined before their
use.

(1) Appearance and colour :
Stones must look
good in appearance and be of uniform colour.
Such a quality is essential for stone to be used for
decoration work. Light coloured stones are
preferred as they resist weathering action in a
better way. Stones with iron oxide should not be
used as the presence of iron oxide disfigures the
stones and brings about disintegration.

(2) Strength :
Stones are used as a compression
member and should have sufficient compressive
strength. In general, all stones possess a
reasonable degree of strength. The crushing
strength of stone should be greater than
100 N/mm^2. igneous rocks have a strength of
around 100 N/mm^2 and some of the
metamorphic rocks also possess these strengths.
But sedimentary rocks have a lower sterngth.

(3) Weight :
in general, good building stones
should have a high weight to resist higher
compressive forces. Good building stones must
have a specific gravity greater than 2.70 . A heavy
stone possess more compactness and less
porosity.

(4) Hardness and Toughness :
Stones must be
hard and tough so that they can resist wear and
tear. Hardness is assessed by scratching and
toughness by hammering. A good building stone
should have a wearing resistance less than 3%,
and if it is more than 3% it is not satisfactory.
Stones used for road work should be hard to
resist wear and tear.

(5) Porosity and Absorption :
All stones possess
porosity. Stones that have a porosity over a
certain percentage are unsuitable for building
purposes. The presence of a higher percentage of
pores may absorb rain, which may deteriorate the
stone. A good stone should not absorb water
more than 0.6% by weight. It must be capable of
withstanding effects of atmosphere. If stones ina
cold cli ate absorb water, they may freeze and
even slt.

(6) Compactness :
A good stone have a compact,
fine, crystalline structure and must be strong. A
compact stone is capable of withstanding the
effect of external agencies effectively.
(7) Fineness of grain :
Stones that are fine grained
are suitable for moulding purposes. Such stones
are easily carved and dressed. Non-crystalline
structures stones are likely to disintegrate under
the action of natural agencies

(8) Resistance to fire :
Stones must be fire resistant,
i.e., they must retain their shape when subjected
to fire. Limestone resists fire up to about 800
degree C. Sandstone can resist fire in a better way.
Although argillaceous stones per poor in strength,
they are highly fire resistant.

(9) Durability :
Stones must be durable. Basically,
stones that have their natural bed perpendicular
to direction of pressure are durable. Durable
stones are those which are compact,
homogeneous, acid resistant and have negligible
water absorption.

(10) Dressing :
dressing is the act of shaping a stone
for decorative purpose or for other purposes. For
this, the stone should possess uniform texture and
softness so that they may be easily dressed. Hard
stone can’t be dressed

(1) Granite : it is a deep-
Seated igneous rock, hard,
durable and available in
different colours. It has
high crushing strength &
capable of sustaining high
weathering.

(2) Basalt & trap : basalt and trap are also of
igneous origin. These are effective solid rocks
which have been formed on the earth’s surface in
the absence of pressure by rapid cooling of the
magma which also carries crystals of various
minerals. These are hard, tough and durable and
are available in different colours

(3) Limestone and chalk : These are sedimentary
rocks which have been formed of remnants of
seaweeds and living organisms consolidated and
cemented together. They are easy to work and
contain a high percentage of calcium carbonate.

(4) Sandstone : this is another form of
sedimentary rock formed by the action of
mechanical sediments. It shows a sandy structure
which is low in strength and easy to work with
the dress. This is available in different colours.

(5) Laterite : this is a
metamorphic rock and
is sandy clayey stone.
It is porous and soft. It
can be cut easily into
blocks and contains a
high percentage of
iron oxide.

(6) Gneiss : it is a metamorphic rock which can be
easily split into thin slab and easy to work on.

(7) Marble : it is a metamorphic rock which can be
easily cut with a saw and can be curved.

(8) Slate : It is also a metamorphic rock which is
black in colour and can be split easily.

(9) Gravel : It is available in river beds in the form
of pebbles and is of different shape.

(10) Quartzite : it is a metamorphic rock which is
hard, brittle and crystalline. It is difficult to work
with and is very durable.

 For foundation, walls, columns, arches, lintels,
roofs, floors, etc.
 For facing work of masonry.
 For railway as ballast.
 For concrete and road construction as coarse
aggregate
 For bridges as floors, piers, abutments,
retaining wall, etc.
 For lighthouses and dams.

 Granite
Granite is used for stone columns , road metal,
ballast for railways, etc. It is found in
Karnataka,Maharashtra,Rajasthan,Punjab,kerala.
 Sandstone
Sandstone is used for building and ornamental
purposes and also as road metal . It is found in M.P.,
Rajasthan ,Tamilnadu etc.

 Limestone
It is used for flooring, roofing,pavements and in general
building construction.It is found in Punjab
Maharashtra,Andhra Pradesh,etc.
 Gneiss
It is used for flooring and pavement and not for major purposes
because of its weakness.It is found in Karnataka,Gujarat and
Tamilnadu.
 Marble
It is used for ornamental purposes,flooring,facing works,etc.It
is found in Rajasthan,Gujarat and Andhra Pradesh.

 Quarrying is the process by which stones are
obtained from rock beds. Quarry is the place from
which the stone is obtained.
Methods Of Quarrying
1.Digging
In soft rocks, stones are merely obtained by digging
with the help of hand tools.like,chisels,pick-
axes,hammers,etc.

2.Heating
This method is adopted by burning certain kinds of fuels and
the exposed surface of the portion of the rock to be separated
.On burning several hours continuously due to unequal
expansion of the rock, the rock gets separated from the mass
with a dull noise.
3.Wedging
Soft stratified rocks can be removed by wedging as there
rocks are in the form of layers and are easy to split. Soft
rocks are removed with the help of pick axes an crow
bars. Limestones, Marble, Slate are removed by this
simple method.

4.Blasting
This technique is employed for quarrying hard and compact
rocks. Blasting is done In some stages.
Holes are made with steel bar with a knife-edged ends called
jumpers or drilling machine.
The drilled holes are charged with an explosive
Of suitable capacity.
Tempting of explosives is done before firing in order to
prevent the blasting within the hole itself.
The fuse is fired carefully. During the explosion, masses of
stones around the hole are removed. A properly packed
explosive shall produce a dull sound followed by displacing of
the mass of rock around it.

Generally the stones obtained from quarrying have a
rough surface and are irregular in shape. The process
of bringing stones to a regular finish is known as
dressing. The purpose of dressing are as follows:
1.To set the stones in a regular shape and appearance.
2.To prepare the stones for a suitable site for easy
handling and transport.
3.To secure proper bedding in stone masonry.
Two types of dressing are in use,
 Quarry dressing
 Site dressing.

Durability of stones depends on the environment at
which they are constructed. For proper durability
assurance, it is necessary to know the agencies which
deteriorate stones.
Deteriorating Agencies Of Stones:
1.Rain
Rain is one among the main causes for wetness on
stones. This wetness is dried by the sun. The process of
wetting and drying causes deteriorating of stones.
2.Climate
In hot climate there are frequent changes in
temperature which results in deterioration. Similarly
Stones exposed to cold climate causes freezing of

Water in pores resulting in the expansion, which
causes splitting of stones.
3.Wind
Wind loaded with grit and dust strikes the stones and
causes wear of the stones. Also moisture penetrate into
the pores causes dampness resulting in deterioration.
4.Vegetation Growth
Vegetation growth along the cleavages of joints of
stones release certain acids by the roots and thereby
cause deterioration.
5.Chemicals
Chemicals of different kinds move and react due to the
usage of different stone such as limestone and
sandstone, thus causing deterioration.

6.Living organisms
Living organisms sometimes form In the joints of stones
and cause instability to the structure . Further, these
holes provide room for the accumulation of moisture
and thereby deteriorate the stones.

Preservation of stones is intended to protect the
structure against the action of weathering agents and
also to protect the good appearance of the face work.
This are the following ways to preserve the stones:
1.Voids existing in the pores are filled properly.
2.By coating with suitable oils like coal tar,linseed oil
etc.
3.By avoiding the moisture into the surface of the
stones.
4.Growth of plants on the joints of stones should be
prevented.
5.Building materials which are inactive with stones
should be used.

1.General building works
Stones used for foundation, walls and superstructure.
Stone with high mechanical strength and the pleasant
colors are widely used, such as sandstones.
2.Building exposed to high wind
Stones with a high crushing strength and the presence
of silica in addition to hardness should be preferred, as
such building are constructed near the sea or location
where more wind prevails.

3.Building in industrial areas
Buildings are mostly subjected to polluted atmosphere
which may contain harmful gases, acids and moisture.
These elements leads to damage, Hence stones that could
sustain the effect of acidity and smoke on them are
preferred.
4.Building exposed to heat and fire
Stones that have high fire-resisting properties or stones
which are free from calcium carbonate can resist
fire.so,this type of stone can be used in buildings which
are frequently susceptible to fire.
5.Facing and architectural items
Facing slabs and stones ,parts of stairs and landings
,parapets and guard rail are made of slabs split from
natural stone and worked on.

6.Road metals and railways ballasts
Road metals and railway ballasts are subjected to high
compression abrasion. Thus stones selected for such
purposes should be able to resist thrust, must be strong
and highly durable. Granite and quartzite preferred for
such purposes.

 Buildings Stones must be tested to assess their
properties to use for various purposes. Some
Tests are simple which can be conducted in the
field and some can be tested only in a
laboratory. Accordingly they are grouped as
• Field Tests
• Laboratory Tests

 Simple Tests that can be performed on the
stone because they are relatively simple. These
include: A
• Absorption Test
• Smith’s Test
• Toughness Test
• Field Hardness Test
• Acid Test
• Crystallization Test

 The test is carried out as follows:
 i. From the sample of stone, a cube weighing about 50gm is
prepared. Its actual weight is recorded as W1 gm.
 ii. Cube is then immersed in distilled water for a period of 24 hrs.
 iii. Cube is taken out of water and surface water is wiped off with a
damp cloth.
 iv. It is weighed again. Let the weight be W2 gm.
 v. Cube is suspended freely in water and its weight is recorded. Let
this be gm.
 vi. Water is boiled and cube is kept in boiling water for 5 hours.
 vii. Cube is removed and surface water is wiped off with a damp
cloth. Its weight is recorded. Let it be gm.
 From the above observations, values of the following properties of
stones are obtained.

 Percentage absorption by weight after 24 hours =
 Percentage absorption by volume after 24 hours =
 Volume of displaced water =
 Percentage porosity by volume =
 Density =
 Specific Gravity =
 Saturation Coefficient =

 This test is performed to find out the presence
of soluble matter in a sample of stone. Few
chips or pieces of stone are taken and they are
placed in a glass tube. The tube is then filled
with clear water. After about an hour, the tube
is vigorously stirred or shaken. Presence of
earthy matter will convert the clear water into
dirty water. If water remains clear, stone will
be durable and free from any soluble matter.

 Rough Test without any rigid specification or
procedure.
 The stones is struck by a hammer to gauge the
toughness of the stone. Force required to break
the stone reflects the toughness of the stone

 Hardness is the resistance of a stone to
indentation, rebound or scratch.
 It is tested by a pen knife with the aid of Moh’s
scale of hardness.

Minerals Moh’s Scale Hardness test
Talc 1
easily scratched with
the thumb-nail
Gypsum 2
scratched by the thumb-
nail
Calcite/ Marbles 3
not scratched by thumb-
nail but easily cut by
knife
Fluorite 4
can be cut by knife with
greater difficulty than
calcite
Apatite 5
can be cut only with
difficulty by knife
Orthoclase/ Feldspar 6
can be cut with knife
with great difficulty on
thin edges
Quartz 7
not scratched by steel,
scratches glass
Topaz 8
Sapphire/ Corundum 9
Diamond 10

 Here, a sample of stone weighing about 50 to
100 gm. is taken. It is placed in a solution of
hydrophobic acid having strength of one per
cent and is kept there for seven days. Solution
is agitated at intervals. A good building stone
maintains its sharp edges and keeps its surface
free from powder at the end of this period. If
the edges are broken and powder is formed on
the surface, it indicates the presence of calcium
carbonate and such a stone will have poor
weathering quality. This test is usually carried
out on sandstones.

 4 cubes of stone with dimension 40mm are taken.
Stones are dried for 3 days and weighed. Then
stones are immersed in 14% solution of Sodium
Sulphate (Na2SO4) for 2 hours. After this stones
are dried at 100 degree Centigrade and weighed.
Difference in weight is noted .Process of drying,
weighing, immersion and reweighing is repeated
at least 5 times. Each time, change in weight is
noted and it is expressed as a percentage of
original weight.
 PERCENTAGE OF WEAR SHOULD NOT
EXCEED 2% FOR GOOD STONE.


 These Tests are complex and require to be done
in laboratories:
• Attrition Test
• Crushing Test
• Impact Test
• Laboratory Hardness Test
• Microscopic Test
• Freezing and Thawing Test

 This test is done to find out the rate of wear of stones, which are used in road
construction. The results of the test indicates the resisting power of stones against the
grinding action under traffic.
 The following procedure is adopted:
 i. Samples of stones is broken into pieces about 60mm size.
 ii. Such pieces, weighing 5kg are put in both the cylinders of Devil’s attrition test
machine. Diameter and length of cylinder are respectively 20cm and 34 cm.
 iii. Cylinders are closed. Their axes make an angle of 30 degree with the horizontal.
 iv. Cylinders are rotated about the horizontal axis for 5 hours at the rate of 30 rpm.
 v. After this period, the contents are taken out from the cylinders and they are passed
through a sieve of 1.5mm mesh.
 vi. Quality of material which is retained on the sieve is weighed.
 vii. Percentage wear worked out as follows:
 Percentage wear =

 Samples of stone is cut into cubes of size 40x40x40
mm. sizes of cubes are finely dressed and finished.
Maximum number of specimen to be tested is
three. Such specimen should be placed in water for
about 72 hours prior to test and therefore tested in
saturated condition.
 Load bearing surface is then covered with plaster
of Paris of about 5mm thick plywood. Load is
applied axially on the cube in a crushing test
machine. Rate of loading is 140 kg/sq.cm per
minute. Crushing strength of the stone per unit
area is the maximum load at which the sample
crushes or fails divided by the area of the bearing
face of the specimen.

 This test is carried out to determine the
toughness of stone. This test requires an
'Impact Testing Machine'. In this test stones are
filled in test cylinder of diameter 25 mm and
height 25 mm. The cylinder is placed on
machine and steel hammer of weight 20 N is
allowed to fall on the specimen in cylinder. The
height of first fall is 1 cm, height of second fall
is 2 cm and so on. The height at which
specimen breaks is recorded. If specimen
breaks at 'n cm' then 'n' is the toughness index
of stone.

 For determining the hardness of a stone, the test is carried out as
follows:
 i. A cylinder of diameter 25mm and height 25mm is taken out
from the sample of stone.
 ii. It is weighed.
 iii. The sample is placed in Dorry’s testing machine and it is
subjected to a pressure of 1250 gm.
 iv. Annular steel disc machine is then rotated at a speed of 28 rpm.
 v. During the rotation of the disc, coarse sand of standard
specification is sprinkled on the top of disc.
 vi. After 1000 revolutions, specimen is taken out and weighed.
 vii. The coefficient of hardness is found out from the following
equation:
 Coefficient of hardness =

 The sample of the test is subjected to
microscopic examination. The sections of
stones are taken and placed under the
microscope to study the various properties
such as
• Average grain size
• Existence of pores, fissures, veins and shakes
• Mineral constituents
• Nature of cementing material
• Presence of any harmful substance
• Texture of stones etc.

 Stone specimen is kept immersed in water for
24 hours. It is then placed in a freezing machine
at -12˚C for 24 hours. Then it is thawed or
warmed at atmospheric temperature. This
should be done in shade to prevent any effect
due to wind, sun rays, rain etc. this procedure
is repeated several times and the behaviour of
stone is carefully observed.

 Types:
• Cement Concrete Blocks
• Artificial Marble
• Terrazzo
• Mosaic Tiles
• Reconstructed Stone
• Bituminous Stone

 Constituents
• Cement
• Fine Aggregates
• Coarse Aggregates
• Water
 Cast in situ or in Molds
 Can be precast with steel to be RCC blocks

 Constituents
• Sand
• Portland/Gypsum/Magnesite cements
 Method 2:
• 60:20:15 plaster in Powder, Pulverized
Marble,Potash Sulphate with 5% solution of glue
and water
 Mostly used in France

 Constituents
• Marble Chips
• White Cement
• Pigment
 Precast or in situ
 Used in Residential Buildings,Bathrooms,etc

 Precast Tiles
 Upper Surface made of Marble Chips
 Available in Different Sizes and Colours

 Made From Debris of limestone quarries by
Crushing
 Mixed with Lime made from dolomite and
heated in a closed retort up to 980˚C to drive
out CO2
 Slaked, Mixed with water and consolidated
into blocks under Pressure.it is then dried and
CO2 is admitted until Carbonization is
Complete

 Diorite and other Granite Stones are
impregnated with prepared tar to form
bituminous stones
 Preferred where
noiseproof,dustproof,wearproof stone surfaces
are needed

 Can be used in areas where natural stone is costly
or unavailable
 Desired Shape and size is obtained easily
 Can be made in situ thus saving dressing and
transport cost
 Practically Defect Free
 Cavities can be made for wiring or plumbing
easily
 Weatherproof
 Strength is Design Based
 More Durable

Building stone

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