5. STONES
The stones which are suitable for the construction of the structures
such as retaining walls, abutments, dams, barrages, roads etc.
Building stones should possess enough strength and durability.
Ex: Granite, sandstone, lime stone, marble, slate etc
10. COMMON USES OF BUILDING STONE:
• Used in foundations of buildings,
• Used in construction of dams, barrages, etc,
• Crushed (powdered) form, is used as artificial sand,
• Used as raw material for manufacturing of cement,
• Used as material for construction of road and railway tracks, if it is
in broken form
• Used as decorative material in buildings,
• Used as parts of buildings such as lintels and arches, etc, It is also
used as thin slabs for building roofing,
• Used for ornamental works in buildings
11. Uses of stone as a building material are:
• Used in stone masonry, where it is naturally available.
• As coarse aggregate in cement concrete (crushed form of rock).
• As a roofing material in the form of slates.
• As a flag or thin slab for paving.
• As a soling material in the construction of highways and runways.
• As ballast for railway tracks.
• As a veneer for decorative front and interior of buildings.
• Limestone for construction of important buildings like temples,
churches and mosques.
• Limestone for the manufacture of cement and as a flux in blast
furnace.
12. Uses of stone as a building material are:
• Used in stone masonry, where it is naturally available.
• As coarse aggregate in cement concrete (crushed form of rock).
• As a roofing material in the form of slates.
• As a flag or thin slab for paving.
• As a soling material in the construction of highways and runways.
• As ballast for railway tracks.
• As a veneer for decorative front and interior of buildings.
• Limestone for construction of important buildings like temples,
churches and mosques.
• Limestone for the manufacture of cement and as a flux in blast
furnace.
13. Characteristics of good building stones:
(1) Hardness
(2) Durability
(3) Appearance
(4) Strength
(5) Toughness
(6) Weathering
(7) Workability
(8) Fire resistance
(9) Specific gravity
14. Characteristics of good building stones:
(1) Hardness:
Hardness indicates resistance to cutting and resistance to abrasion (rub with each
other). Stones are generally used in roads and railway tracks construction. Ex: Loss
Angles Abrasion test.
(2) Durability:
Durability is the power of stone resistance from atmospheric and other external
effects.
It depends upon:
• Chemical composition,
• Physical structure,
• Resistance to weathering effects,
• Place where it is used
15. (3) Porosity and Absorption:
• Stone can hold water either through porosity or absorption.
• Less porous stones absorb less moisture. Porous stones are not suitable for
building construction.
(4) Decomposition:
Gases and acids in rain water dissolve some constituents of stone and cause the
stone decay.
(5) Disintegration:
In cold countries water freezes and expands and thus disintegrates the stones.
(6) Reliability:
When exposed to fire stone, it should resist fire.
Characteristics of good building stones:
16. Appearance and color:
Bright color stones are preferred for architectural purpose but those are soft
and less durable.
Physical Strength:
Crystalline structures are more durable than non-crystalline structure stone
Seasoning Qualities:
A good building stone should have good seasoning qualities. The period 3-6
months are enough for seasoning.
Fire resistance:
A good building stone should be fire resistant. Basalt and trap resist fire but
some varieties of igneous and metamorphic stones are very weak against fire.
Characteristics of good building stones:
17. Rocks
Sedimentary (S) Rocks
Ex: sand stone, lime, mud stones
Metamorphic (M) Rocks formed due to Pr. & temp
If Pr. is high, Ex: marble/quartzite
If temp is high shale/schist
Igneous (I)Rocks formed due to temp
Ex: basalt/granite
in extreme temps magma
Formation is f(Pr. and temp)
19. Classification of rocks (stones) or varieties of stones:
There are three main classes of rocks.
(1) Chemical classification:
Chemically stones are stones are classified into three groups.
(i) Argillaceous Rocks:
Argillaceous or clay stones are those stones which contain (alumina
Al2O3) (clay) as principal constituent. These stones are less durable
stones. All clay stones belong to this group.
Ex: Slate, Laterite, etc.
20. (ii) Silicious Rocks:
The stones which contain (Silica SiO2) as principal constituentare
called silicious rocks. These stones are durable stones.
Ex: granite, quartzite and sand stone etc.
(ii) Calcareous Rocks:
The stones which contain calcareous material (CaCO3) as
principal constituent are called calcareous rocks. They also
contain some proportion of siliceous and clay matter.
Ex: marble stone and lime stone, etc.
21. (2) PHYSICAL CLASSIFICATION:
Physically rocks are classified as:
(i) Stratified Rocks:
The rocks which are split into thin slabs or layers easily are called
stratified rocks.
Ex: Slate, Sand stone and Lime stone.
(ii) Unstratified Rocks:
These rocks cannot be easily split into thin slabs or layers are called
unstratified rocks. Alligneous rocks are essentially unstratified and
metamorphic rocks may be either stratified or unstartified.
Ex: Granite, Basalt
(iii)Foliated rocks:
These rocks have a tendency to be split up in a definitedirection
only. Foliated structure is very common in case of metamorphic
rocks.
22. (3) GEOLOGICALCLASSIFICATION:
Stones are classified into three groups as per this calssification.
(i) Igneous or Primary Rocks:
•These are primary rocks which are formed from molten magma.
They represent different structural features depending upon the
condition of solidification and composition. Generally igneous rocks
are strong and durable.
•These are also called unsratified or eruptive rocks.
Ex: granite, basalt, trap, etc.
23. (ii) Sedimentary or Secondary Rocks:
• These rocks are formed by transportation of particles from one
location to other place.
• These are also called aqueous and stratified rocks. (or)
• The rocks which are formed by gradual deposition are called
Sedimentary Rocks.
Ex: Lime stone, sand stone, etc.
24. (iii) Metamorphic or TertiaryRocks:
Rocks which are formed due to metamorphic action of pressure or
internal heat or by both (or) alteration of original structure due to heat
and excessive pressure are called Metamorphic Rocks.
Ex: Marble etc.
25. Tests on Building Stones
•Following are different tests on building stones:
•Acid test
•Attrition test
•Crushing test
•Freezing and thawing test
•Hardness Test
•Impact test
•Durability Test
•Microscopic Test
•Smith’s Test
https://www.youtube.com/watch?v=7R-kSKws444
https://civiljungle.com/tests-on-stones/
26. Acid Test on Building Stone
This test is carried out to understand the presence of calcium
carbonate in building stone.
This test gives the weathering resistance of the stone.
A good building stone maintains its sharp edges and keeps its surface
free from powder at the end of this test.
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 sand stones.
27. Attrition Test on Building Stone
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.
Quantity of material which is retained on the sieve is
weighed.
Percentage wear worked out as follows:
Percentage wear = (Loss in Weight/Initial Weight) x 100
28. Crushing Test on Building Stone
Stone is cut into cubes of size 40 x 40 x 40 mm are finely
dressed and finished.
Specimen should be placed in water for about 72 hours
before testing.
Load is applied axially on the cube in a crushing test
machine.
Rate of loading is 140 kg/sq.cm per minute.
29. Freezing and thawing test
Stone specimen is kept immersed in water for 24 hours.
It is then placed in a freezing machine at -12 degC 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.
30. Hardness Test on Building Stone
This test is carried out to determine the hardness of a
stone.
A cylinder of diameter 25mm and height 25mm is taken
out from the sample of stone.
Dorry’s testing machine is used for testing.
The coefficient of hardness is found out from the following
equation:
Coefficient of hardness = 20 – (Loss of weight in gm/3)
Alternatively, scratch the surface of stone with a knife
31. Impact Test
To determine toughness of stone, impact test is carried out.
The resistance of stones to impact is found by conducting tests in
impacting the testing machine.
It consists of a frame with guides where a metal hammer weighing 13.5
to 15 kg can freely fall from a height of 380 mm.
32. Impact Test
Aggregates of size 10 mm to 12.5 mm are
filled in a cylinder in 3 equal layers, every layer
being tamped 25 times.
The same is then transferred into the cup and
again tamped 25 times. The hammer is then
allowed to fall freely onto the specimen 15
times.
The specimen is then sieved through a 2.36
mm sieve.
Then, Impact value = W2 / W1
where,
W2 = Weight of Fines.
W1 = Original Weight.
The recommended impact values for various
works are:
(a) for wearing course ≯ 30%
(b) for bituminous macadam ≯ 35%
(c) for water-bound macadam ≯ 40%
33. Microscopic Test
Geologists take thin sections of stones 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.
34. Smith’s Test
This test is performed to find 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.
This test is a qualitative test
35. Durability Test
Durability or soundness test is performed to fine out the
capacity of the stone to resist disintegration and
decomposition.
Durability = change in the mass in%
36. Tests on Building Stones
Water Absorption Test
The test is carried out as follows:
From the sample of stone, a cube weighing about 50gm is
prepared. Its actual weight is recorded as W1 gm.
Cube is then immersed in distilled water for a period of 24
hrs.
Cube is taken out of water and surface water is wiped off
with a damp cloth.
It is weighed again. Let the weight be W2 gm.
Cube is suspended freely in water and its weight is recorded.
Let this be W3 gm.
Water is boiled and cube is kept in boiling water for 5 hours.
Cube is removed and surface water is wiped off with a damp
cloth. Its weight is recorded. Let it be W4 gm.
From the above observations, values of the following
properties of stones are obtained.
