Building stones II

1. Building Stones-II

2. Some common building Stones
• Igneous rocks by virtue of their texture and
minerals present in them have the ability to
take very good polish and thus are become
increasingly popular for face work .

3. Granite
Granite
• Granite is a plutonic igneous rock because it is
formed due to solidification of magma at
greater depth. It is holocrystalline and leucocratic
rock because it is complete crystalline and light
colored rock.
Minerals present in granite
• Granite is composed of only primary minerals.
Among these, feldspar and quartz occur as
essential minerals and common accessory
minerals are such as hornblende, biotitic.

4. Granite

5. Granite
Structure
• Granite is compact, dense, massive and hard
rock. But mural joints occur in some, dividing the
rock into number of rectangular blocks,
thereby facilitating the quarrying processes.
Texture
• Granites typically exhibit an interlocking,
coarse grained texture. Granites are usually
equigranular. But some shows inequigranular,
textures and are called granite porphyries.

6. Granite
Appearance of Granite
• Granite is generally medium to coarse
grained and grayish or pinkish in color.
Mode of Occurrence and relative abundance
• Granite rock occur in the form of very large
igneous bodies such as batholiths, stocks,
often they occur as cores of mountains
ranges and are thus related to mountain-
building activity.

7. Granite

8. Granite
Physical properties of Granite
• Granite is massive, unstratified and dense,
therefore it is very strong and competent
• Granite has an interlocking texture, which keeps
minerals firmly held and this cohesion contributes
greater strength.
• Granite is either equigranular or has porphyritic
texture.
• Since granite is massive and formed from melt it
is neither porous nor permeable. So no
saturation or percolation by water is possible.

9. Physical properties of Granite

10. Physical properties of Granite
• Granite is very rich in silica; therefore it is very
much resistant to decay
• Presence of mural joint permit easy quarrying
• Presence of rift and grain permit easy dressing.
• Granites have the ability to take superb polish, and
hence are becoming increasingly popular for face
works of construction.
• Granites offer reasonable fire and frost resistance,
because minerals are not many and these rocks are
free from fractures.

11. Basalt
Basalt
• The term basalt was first used by pliny to refer a black,
ferruginous rock. Now the term is applied to very fine
grained, black volcanic rock in which plagioclase feldspar
and mafic minerals occur approximately in equal amounts.
Minerals
• Basalt is a simple mixture of Labradorite, augite(essential)
and iron oxide. It is similar to dolerite in mineral content.
Biotitic and hornblendes are the other rare accessory minerals.
Structure and texture
• Vesicular and amygdal structures are the most common in
basalt. Columnar structures and flow structure are also
observed in some cases.

12. Basalts

13. Basalts
Availability and mode of Occurrence
• Basalts are the most abundant among volcanic rocks. Their
quantity is five times greater than all other volcanic rocks put
together. They occur as flat or slightly inclined lava flow.
Properties and Uses
Massive basalts are highly durable and the strongest. This is
because not only they are compact, hard and tough but also
more fine grained than dolerite. For this reason basalts are
extensively used as building stones.
As a road metal, the basalts are excellent for macadam and
bitumen roads. They are hard, tough and wear-resisting
and have good binding properties.

14. Limestone
Limestone
• Among the sedimentary rocks, in the order of
abundance, limestone rank third, next to shales
and sandstones. These comprises 5 % of all
sedimentary rocks occurring on the earth’s
surface.
• Limestone are typically non-detrital rocks. They
are formed either chemically, due to precipitation
of calcium carbonate from surface water. Or
organically, due to accumulation of hard part
of organisms

15. Limestone

16. Limestone
• In hand specimens, limestones show different
colors like white, gray, buff, yellow and black.
• If the limestone have formed out of chemical
precipitation, they are extremely fine grained.
In case of organic, limestone have formed out
of chemical precipitation, they are extremely
fine grained. In case of organic, limestone, the
grain size may vary depending on the type of
organisms responsible for its formation.

17. Limestone

18. Limestone
Types of limestones
• Massive compact fine grained limestones with
grey or any other light color are common in
nature the porous types are yellowish, brownish
etc.
• The other important types are
• Chalk, stalactites, stalagmites and drip stones,
travertine, kankar, fossiliferous or shell
limestone, flaggy limestone, lithographic
limestone, magnesium limestone, argillaceous
limestone, siliceous limestone.

19. Limestone

20. Limestone
Porosity and permeability
• Limestones are the most deceptive and most
unpredictable rocks in terms of porosity and
permeability. This is because of the inherent character
of limestone, that is getting corroded by carbon
dioxide, bearing water at anytime. But inside they
may have solution cavities and solution channels of
varying magnitudes. Highly irregular and uneven
topography formed this way in limestone region is
known as Karst topography.
• Thus the range of porosity and permeability is
unreasonable large in limestone. Therefore they are
either one of the best or worst aquifer in nature.

21. Limestone
Civil Engineering and Other Uses
• Massive and compact limestones are
reasonable competent to support civil
engineering structures. They are suitable as
road metal, railway ballast and as construction
material but may not be very durable.
Further if hollow, their load-bearing
strength also will get reduced.

22. Limestone

23. Marble
• The term marble is derived from marmore “a
shining stone”. Like quartzite, marble is also a
parametamorphic rock. It is a calcareous
metamorphic rock formed out of the thermal
metamorphism of limestone. Though it is not
very hard or strong it is the most valuable rock
occurring in nature. Its value is due to its pleasant
color, good appearance, easy workability,
charming translucency and the availability to
take brilliant polish. It is also valuable because it
is not abundantly available in nature.

24. Marble

25. Marble
• Marble shows the following properties
• Color: Some marbles show uniform color
throughout the rock. Pure marble is milky
white in color. Pleasant shades of green, yellow,
brown, blue or grey color may also occur.
• Grain Size: Fine medium or coarse grained, but
the rock is equigranular.
• Texture and structure: Marble shows a typical
granulose structure. This is because calcite,
which is neither platy nor prismatic, is the most
predominant mineral of the rock.

26. Marble

27. Marble
• Hardness: Marble is relatively soft and is easily scratched
with a glass piece or penknife. For this reason, marble can be
conveniently cut mechanically.
• Appearance: When a hand specimen of polished marble is
turned around, a twinkling appearance is noticed because
the surface of the rock passes through cleavage planes, it is
reflected giving a twinkling appearance.
• Translucency: Pure white marble are reasonably
translucent, which is an additional virtue of marble.
• Mineral Present: Just as quartz is the most predominant
mineral constituent of quartzite, so is calcite in marble.

28. Marble

29. Properties and Uses of Civil
Engineering Importance
• Occurance: As a geological formation, marble is found in
the form of thick or thin beds in association with other
metamorphic rocks like gneiss, schists and slate.
• ‘as already mentioned, marbles are well known for their
beautiful colors, pleasing appearance and easy
workability. Being denser and less porous, it is of course,
stronger than limestone. Marbles occurring in nature are
quarried, dressed and used as building stones for
temples or other construction. Marbles provide aesthetic
beauty and a pleasing appearance to the construction. They
are used in innumerable ornamental, decorative and
monumental works where carving, engraving and
polishing etc are involved.

30. Marble

31. Sandstones
Sandstones
• Among sedimentary rocks, sandstones are
very abundant and are next only to shales in
this respect, they represent nearly 15 % of
the sedimentary rocks of the earth’s crust.
These are very common clastic rocks made up
of sand and are described as arenaceous rocks.
Unlike conglomerates, sandstones are
stratified and sometimes fossiliferous too.

32. Sandstones

33. Sandstones
• Sand grains in sandstone are mostly quartz, In
addition to these the other minerals are mica, magnetite
and feldspar.
• Nature of Sand Grains and Cementing Materials
• Based on the size of sand grains the sandstones may be
coarse grained, medium grained or fine grained. But
generally the sand grain in any sandstones will be
nearly of the same size.
• The sand grain present may be rounded or surrounded
or angular in shape.
• Sandstones occur in different colors such as white, red,
yellow grey and green. The color of sand grain is due
to cementing material.

34. Sandstones

35. Sandstones
Porosity Permeability and Uses
• By virtue of their mode of formation, like
conglomerates, sandstones also generally
porous and permeable. The porosity of
sandstones is dependent on the size and shape
of the sand, Further the degree of cementing
also contribute to the porosity. Therefore
sandstones vary considerable in their porosity
and permeability.

36. Sandstones
• From the civil engineering point of view,
however, careful study is necessary before
considering a rock as competent or incompetent,
useful or useless. When sandstone is
considerably porous and permeable i.e.. when
the degree of cementation is less, it will not
make up a good rock. & if the sand stone are well
cemented and if the grains are angular and quartz
in composition, the siliceous sandstone are the
best and highly satisfactory for all civil
engineering purpose.

37. Sandstones

38. Gneiss
Gneiss
• Among different metamorphic rocks, gneiss is
more widespread and abundant than others.
• Gneiss is a general name given to any
metamorphic rock which shows a gneissose
structure. In many cases, gneisses are derived
from granites. Hence, the minerals composition,
grain size, color, etc, will be more or less
similar both in granite and gneisses. For this
reason, it is commonly referred to as granite
gneiss.

39. Gneiss

40. Gneiss
• A few details of its physical description are as follows
• Diagnostic character: Foliation Present
• Color: different shades of gray and pink, but generally
pale colored.
• Grain size: Medium to coarse grained
• Texture and structure: Generally equigranular, but
sometimes porphyroblastic. Foliation i.e.. alignment
of minerals is characteristically seen.
• Minerals Present: Feldspar and quartz usually make
up the bulk of a gneiss.

41. Gneiss

42. Gneiss
Origin
• Gneisses are usually formed out of
dynamothermal metamorphism of granite,
sandstones and conglomerates, etc. Among
these, granite gneiss is far more abundant than
all others.
Occurrence
• Due to close mineralogical and other
resemblance, granite gneisses may be treated as
varieties of granites themselves.

43. Gneiss
• As gneiss is a silica-rich rock, it is durable
• By virtue of mineralogical similarity to granite,
gneisses also have pleasing color
• Gneiss is reasonably non-porous and impermeable,
contributing to its strength.
• The gneissose structure with its alternating bands of
contrasting colors on polishing, produces a very good
appearance.
• The foliation, to some extent, improves the
workability of gneiss.
• The occurrence of gneiss in plenty, in many places,
makes it an important building stone or material

44. Gneiss

45. Laterite
• It is a Sedimentary rock composed of mostly of oxides of aluminium
with varying amounts of oxide of iron.
• Texture and Structure
• The rock is formed from chemical decomposition of alkaline igneous
rocks by leaching of some components. This results in Spongy structure
and porous texture.
• Building Properties
• The Laterites are light to dark red in color depending upon the
quantity of iron oxide in their composition. They are poor in
compressive strength, which varies from 20- 30 kg/cm2.
• Laterite are used only in ordinary construction and mostly as road metal
rather than building stone.
• Indian Occurrence
• Latterite are found in Maharashtra, Madhya Pradesh, Bihar, Orissa,
and also in some southern states like Andhra Pradesh, Madras, and Kerala.

46. Laterite

47. Slate
• Slate is a dense, fine grained, argillaceous,
parametamorphic rock. It has the unique
character of slaty cleavage. It is formed out of
dynamic or regional metamorphism of shale. By
virtue of its cleavage character. It is formed out
of dynamic or regional metamorphism of shale.
By virtue of its cleavage character, it splits easily
into very thin sheets or slabs of considerable size.
Extreme fine grained size, absence of reaction
with acid, slaty cleavage and shining on surfaces
are diagnostic character of slate.

48. Slate

49. Slate
• Physical properties of slate are as follows
• Color: Slate usually exhibit uniform color. Generally,
they are black or dark grayish black. But other colors
like brown, red, green and grey and yellow occurs.
• Grain Size: Slate is very dense looking and extremely
fine grained. Individual grains are too fine to be seen
from the naked eye.
• Texture: Foliation is clearly visible through constituent
minerals are fine and unrecognizable. The layers of
shale which are differently colored appear as ribbons or
bands in slaty formation in fields.

50. Slate

51. Slate
• Bedding and fossil content: Some slate retain
their bedding or lamination character of shale
as a relict feature. Fossil may occur rarely but
such fossil are often distorted and squeezed out of
their original shape.
• Hardness: Slates are relatively soft when
compared with other metamorphic rocks.
• Minerals Present: Slates are mainly made up of
secondary mica and quartz other minerals
which may occur are biotite, talc, feldspar etc.

52. Slate

53. Slate
Origin
• The majority of slates are the result of dynamic
metamorphism of argillaceous sediments. A
few slates may also be formed from altered
basic igneous rocks.

54. Properties and Uses of Civil
Engineering Importance
• Slates are dense, fine grained, impermeable and
relatively resistant to decay. However, since
slates are soft and incompetent, they cannot
withstand great loads. So they are not suitable
for foundation purposes. Due to cleavage
character and softness, they split easily. Hence
they cannot be used as building stone. But since
slates are impermeable and can be split into thin
but big slab of uniform thickness, they can be
conveniently used for roofing, flooring, mantle
and shingles etc. they can also be used as
shelves.

55. Slate

56. Qualities Required In Stones
1. Strength
• For ordinary types of stone-houses, any
good rock being traditionally used for the
same purpose will normally possess
sufficient strength to bear usual loads. But
engineer must satisfy himself about all the
strength parameters only after through testing
in accordance of codes.

57. Qualities Required In Stones
• Compressive Strength
• It is the main quality of a building stone
expressed as the maximum load per unit area
at which the stone starts breaking.
• This property can be easily tested in a civil
engineering laboratory on the Universal
Testing Machine ( U.T.M)
• The compressive strength of most commonly
used stones has been found to be 280 – 2800
kg/cm2

58. Qualities Required In Stones
Traverse Strength
• It is the resistance offered to a bending
loads. In the case of building stones it is to
be evaluated only when the stone is to be
used as a beam or lintel. This property is
commonly determined as modulus of rupture R
the R value for various stones vary between
20 – 300 kg/ cm2

59. Qualities Required In Stones
Shear Strength
• Stones of good quality are often used as
piers and columns, especially in
monumental buildings. In Such Situations,
the stone is to withstand shear type of loads.
Hence it must posses sufficient strength.
• The shear strength of common buildings
stones lies between 70 – 160 kg/ cm2

60. Qualities Required In Stones
2. Hardness
• “Hardness of stone may be defined as its capacity to
resist scratching or abrasion”
• The hardness of stones depend on mineral
composition. The significance of this property lies in
its resistance to wear and tear during its use in
where rubbing action due to natural agencies or by
artificial causes such as in flooring is involved thus
stones facing the prevalent sand laden winds in an area
should be chosen with great care as soft stones may be
worn out most easily and quickly then expected.

61. Qualities Required In Stones
3. Toughness
• Is a property related to both hardness and
strength. It is defined as the capacity of
stones to withstand the impact loads.
• Thus stones to be used in foundations under
heavy machines when vibration may be a
common phenomenon may not only be hard
and strong but very tough also.

62. Qualities Required In Stones
4. Water Absorption
• Building Stones are liable to come in contact
with water used in foundation and exterior
walls. Ideally, they must not absorb moisture
because can become cause of many troubles.
Water absorption may be defined as ‘Quantity of
water absorbed by a stone till saturation’ water
absorption is especially significant when a stone
is used in foundations in cold climate where
freezing temperature is a common phenomenon.

63. Qualities Required In Stones
• In such situations water within the pores may
freeze and exerts disintegrating stresses.
Disintegration of stones by freezing water is
known as frost action. And this process may
spoil porous stones used on outer surface or
as costly buildings unless they are protected
from rains.

64. Qualities Required In Stones
5. Appearance
• Stones are available in almost all colors from milk
white to blood red to pitch black. Naturally,
appearance of a stone for a building becomes an
important factor for selection.
• Taj mahal at agra was constructed with white marble
although red and green or pink marble are available.
For red fort in Delhi, the red color sand stone was used
to indicate royalty.
• Aesthetically light color are preferred in the exterior
of the building. Appearance have no significance
when the stone is used in obscure positions such as
in foundations.

65. Qualities Required In Stones
6. Workability
• Stones when obtained from their natural place of
occurrence- the outcrops are quite irregular
masses. They require a lot of work on them before
they can be converted to appropriate shapes for used
in construction. Shapes required may vary from
ordinary rectangle to square block of small sizes.
The process of giving a proper shape dimension
and surface finish to a raw stone before it is fit for
use in construction is called dressing .

66. Qualities Required In Stones
• It has been observed that all the stones cannot
be dressed or worked easily. The cost of
dressing stones per block may become an
important factor in selection of stones.
• Igneous rocks like basalt and granites are
very difficult to dress and polish. Marble
and limestone however are comparatively
soft and can be given any shape, finish and
polish at comparatively low cost.

67. Qualities required in Stones
6.Durability
• It denotes the period in years for which a stone
may stand practically unaltered after being
used in construction,
• A durable stone must
• Withstand load
• Must keep the original appearance
• Must resist the effect of cold and heat
• Must not suffer deterioration and decomposition by
gases and surrounding industries.

68. Qualities required in Stones
• Obviously the durability of stone does not depend on
a single property but rather a set of properties
discussed above.
It may be summarized that a stone will be durable when :
• It has high strength for designed loads
• It has uniform close packed and dense structure with
very low absorption value
• It is made up of vey hard and resistant mineral
constituents
• It is resistant to chemically reactive gases such as
sulphur dioxide, carbon dioxide etc.

69. Deterioration and Preservation of
Stones
• Stones, like all other materials used in
construction, deteriorate with time. Some
undesirable changes are likely to develop in
them after years of exposure to natural
agencies like wind, water, and temperature.
Appearance gets definitely affected.
Strength qualities may not be easily affected
with time, but when they do, the durability
and safety of the building get endangered.

70. Deterioration and Preservation of
Stones

71. Deterioration and Preservation of
Stones
Causes of Deterioration
• There may be either physical or chemical or
both in nature.
Physical Causes
• Among these, the frost action, temperature
effect and the rubbing action of winds may
be quite significant.

72. Deterioration and Preservation of
Stones

73. Deterioration and Preservation of
Stones
(i) Frost Action
• In Cold Humid Climates, porous stones may
absorb moisture from atmosphere quite easily.
When this happens in winters, water within the
pores freezes and expands exerting tensile
stresses from within. This nature slow and steady
process, called frost action is repeated winter after
winter. Frost action is capable of Splitting and
Spalling on the surface of Stone.

74. Frost Action

75. Deterioration and Preservation of
Stones
(ii) Temperature Changes
• Stones like all other materials expand on heating and
contract on cooling. Their Coefficient of expansion, is of
course negligible when considering on short term basis. But
when considered for many scores of years and especially
when stone are made of different minerals having
different expansion and contraction coefficients some
minor stresses do develop within the stone exposed to
heating action of the sun.
• The Surface of stones start getting affected, apparently
insignificantly in the beginning. The effect deserves due
consideration when stone are used in arid region on the
exterior portion

76. Deterioration and Preservation of
Stones

77. Deterioration and Preservation of
Stones
Wind Action
• Strong winds rich in sand and dust particles act as
virtual sand papers. These are capable of polishing of
stones when they have a uniform texture and composition.
But when the stones are made up of minerals
constituents of different hardness, the soft minerals
constituents of different hardness, the soft minerals get
polished more and more and may be gradually removed
by pitting. The adjoining mineral may also fall apart on
losing the grip. Hence a process of slow physical
disintegration starts on the surface of the stone exposed to
wind action.
• Wind action is a powerful scabbing process in areas of
strong winds lying on the borders of deserts.

78. Wind Action

79. Deterioration and Preservation of
Stones
Chemical Causes
• The atmospheric moisture and some of the atmospheric gases
and vapors emanating from the industries are quite harmful for
many types of stones exposed to their direct attack.
• (i) Water Vapors
• Water on chemical combination with atmospheric carbon
dioxide makes carbonic acid. This acid has mild corrosive action
on some stones. Thus it can slowly attack and eat up the strongest of
rocks
• (ii) Limestone and marbles
• Are both composed of calcium carbonate ( CaCO3). In
Industrial towns where SO3 vapors are emanated from many
industrial chimneys, they mix with atmospheric moisture and
make an injurious sulphuric acid. The acid reacts with carbonate
of the stone converting that into a sulphate and in the process
tarnishing the surface of the stone.

80. Deterioration and Preservation of
Stones

81. Deterioration and Preservation of
Stones
• The so hot debated controversy of threat
deterioration to the marbles used in Taj
Mahal from the sulphate emanation Mathura
Refinery are based on the this basic fact.

82. Preservation of Stones
• It is quite possible to protect the stone from quick
deterioration by adopting one or more of the
following methods:
Careful Selection
• While selecting stones in a given area, a general
assessment about the weathering resistance of the
stone can be formed from quarries, old exposure or
from the stones used in the buildings. If a stone has
shown too much deterioration at those places, it is
likely to deteriorate in a similar manner when used in a
building construction in a new building. Hence it may
not be selected for use in similar situation exposed to
weather.

83. Careful Selection

84. Preservation of Stones
• Similarly, if a stone is to be used in an already
established or proposed industrial town, its
composition must be given due consideration.
Limestone, marbles and dolomites, all carbonated
rocks, are likely to deteriorate fast, especially on
exposed parts. We should prefer use of siliceous
stones like sand stone and quartzite instead.
• If the area has strong winds and located close to
deserts, we should select only fine textured stones
having uniform composition and good hardness.
E.g. quartzites instead of granites.

85. Preservation of Stones

86. Preservation of Stones
(ii) Careful Construction
• While constructing a stone house , in part or complete, a set of
precautions can increase the life and beauty of the building to a
considerable extent.
• Such as:
• Stones of proper size and shape should only be used with a mortar of
matching quality so that no open spaces are left for moisture and gases to
seep or get in.
• No ledge of stone should be left projecting out as it may act as a
gathering place for water during rains.
• Use of different stones in alternate layer or even in the same layer
should be avoided. Homogeneity in the stone construction is considered a
better policy.
• Only well seasoned stones be used in construction, when stratified,
their bedded planes should be given proper consideration while placing
them in load bearing position.

87. Preservation of Stones

88. Preservation of Stones
(iii) Application of preservatives.
• When a stone has already been used and there is a risk of its
deterioration because of environmental conditions, a preventive measure
may be taken by applying some well known preservative on it.
• A preservative is a oil or a paint or a solution which when applied on a
stone protects it from the direct attack of some deteriorating agency.
A really effective preservative must be
• Easily applicable
• Easily penetrating
• Unleachable
• Economical
• Further the preservative must not change the natural appearance of
the stone and produce odd smell

89. Preservation of Stones

90. Preservation of Stones
• A large number of preservative are available for preventing
the deterioration of stones. The following are mentioned
below
Linseed oil
• It is used both in cold and boiled form. Boiled linseed oil
will change the appearance of stone to a darker shade.
Paraffin
• It is commonly used in the dissolved form in naphtha. It
also interferes with the original color of the stone.
Coal Tar
• It is cheap and effective preservative except it changes
the look of the stone.

91. Preservation of Stones

92. Preservation of Stones
Baryta Solution
• It is simply a solution of barium hydroxide and has
been found resistant against sulphate attacks on
stone surface. It reacts with calcium sulphate forming
barium sulphate, which is more stable and protects the
surface of the stone from further deterioration.
Paints
• When stone deterioration has spoiled the
appearance of a stone to a considerable extent, best
course would be to cover it with a paint. It will stop
further deterioration and also improve the look.

93. Artificial Stones
Definition
• It is a stone like mass made by mixing together crushed
stone pieces with cement and water in presence of
coloring pigments .
Types
• Artificial stone in the broadest since of the term, may be
best called a type of cement concrete, this can be made
in various shapes and in different composition. The
component of artificial stones are decided by the engineer
and pre-mixed proportions with cement and water. After
through mixing, the paste is filled in proper moulds and
allowed to set in. Thereafter they are removed and
placed on plain protected surface for curing and
hardening.

94. Artificial Stones

95. Artificial Stones
• Grooves, cavities and hollow can be provided
in the stone as desired at the molding stage.
• Terrazzo and Mosaic are the simple and
common variety of artificial stones. In terrazzo,
it is marble in the form of chips that is the main
material used with the cement mix for making the
stone.
• In the Case of tiles, it is the top surface of the
normal cement concrete in which marble chips
are spread uniformly during the casting
process.

96. Terrazzo and Mosaic

97. Artificial Stones
Uses
• Artificial stones have the general properties
and appearance of natural stones to some
extent. These have the advantage that these
can be casted and cured at the place of their
use and in the any desired shape. Moreover,
these stones often can be given any desired
polish. For these reasons artificial stones are
used in buildings to give decorative looks.

98. Artificial Stones

99. References
• Building Construction : Dr B.C. Punmia
• Civil Engineering Material : Prof. Singh
• Internet Web Sites

100. Thanks…