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 (mono-mineralic) or of several minerals (poly-mineralic).
1. STONE
GROUP NO: 02
ABHAY KUMAR
AKSHAY S KUMAR
D.PRASHANTH
K.L.RAVI CHANDU
LABEEB
MOHAMMED MUSTAFA ALI
RIYA SUSAN
VAMSHI KRISHNA RAO K
2. CONTENTS
INTRODUCTION
SEASONING OF STONE
CHARACTERISTICS OF GOOD BUILDING STONE
TESTS ON STONES
DURABILITY TEST
COMPRESSIVE STRENGTH TEST
COMMON BUILDING STONES AND THEIR USES
3. INTRODUCTION :
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 (mono-mineralic) or of several
minerals (poly-mineralic).
Mono-mineralic rocks are quartz sand, pure gypsum, and magnesite.
Poly-mineralic 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, e.g. brick,
glass, items for concrete and mortar.
4. SEASONING OF STONE
A freshly cut stone carries some natural moisture known as quarry sap.
Quarry sap makes the stone soft and workable.
The quarry sap is a mineral solution and reacts chemically with the mineral
constituents when it is exposed to atmosphere after quarrying.
Thus the stone becomes harder and compact.
All the stones should be seasoned before they are used in structural work.
Seasoning can be done for a period of 6 to 12 months.
5. CHARACTERISTICS OF GOOD
BUILDING STONE
We use stone in different constructions. It is necessary to find their suitability
under different condition. The following properties need to be examined before
their use.
APPEARANCE AND COLOUR :
Stones must look good in appearance and be of uniform colour.
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.
6. STRENGTH :
Stones are used as a compression member and should have sufficient
compressive strength.
The crushing strength of stone should be greater than 100 N/mm2.
Igneous rocks have a strength of around 100 N/mm2.
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 2.7.
A heavy stone possess more compactness and less porosity.
7. 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.
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 in a cold climate absorb
water, they may freeze and even sit.
8. 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.
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.
9. RESISTANCE TO FIRE :
Stones 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.
DURABILITY :
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.
11. TESTS ON STONES
DURABILIY TEST:
The durability test is performed to find out the capacity of stone to resist
disintegration and decomposition.
Durability value = change in mass = (M1-M2)X100.
12. COMPRESSIVE STRENGTH
Samples of stone is cut into cubes of size 40x40x40 mm.
Sizes of cubes are finely dressed and finished.
Minimum 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.
13. COMMON BUILDING STONES AND
THEIR USES
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.
14. 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
15. 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.
16. 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.
17. 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.
18. Gneiss : It is a metamorphic rock which can be easily split into thin slab and easy
to work on.
19. Marble : It is a metamorphic rock which can be easily cut with a saw and can
be curved.
20. Slate : It is also a metamorphic rock which is black in colour and can be split easily.
21. Gravel : It is available in river beds in the form of pebbles and is of different
shape.
22. Quartzite : It is a metamorphic rock which is hard, brittle and crystalline. It is
difficult to work with and is very durable.
23. USES OF COMMON BUILDING STONE
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.
24. USEFUL BUILDING STONES IN
INDIA
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.
26. 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.
29. Selection of stones for various works:
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.
30. 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.
31. 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.