Construction material, aggregrates

1. AGGREGATES

2. 2
Aggregates are inert
materials which are mixed
with binding material such as
cement or lime for
manufacturing of mortar or
concrete. Aggregates are
used as filler in mortar and
concrete and also to reduce
their cost.

3. AGGREGATES

4. DEFINITION
• A combination of different sizes and shapes
normally of stones. Maximum size is 75 mm.

5. USES OF AGGREGATES
• As an underlying material for foundations and
pavements
• As an ingredients in Portland cement concrete and
asphalt concrete.

6. SELECTION OF AGGREGATES
• aggregates shall be hard, durable and clean and free
from adherent coatings and organic matter and shall
not contain appreciable amount of clay.
• Aggregates shall not contain harmful impurities such as
iron pyrites, alkalis, salts, coal, mica, shale or other
materials which will affect hardening and attack
reinforcement.

7. CLASSIFICATION OF AGGREGATES
Based on size:
• classified into 2 categories:
• fine aggregates - those aggregates which pass through
4.75 mm sieve or aggregates with size less than 5 mm.
• Coarse aggregates – those aggregates
Passing through 75 mm sieve and entirely
retained on 4.75 mm sieve OR those
aggregates with size greater than 5 mm.

8. CLASSIFICATION OF AGGREGATES
Based on source or method of manufacture:
• classified into 2 categories:
• Natural aggregate/uncrushed aggregate- Those
from the river beds, river sand and ex-mines. Normally
rounded in shape and have smooth surface texture.
• Manufactured aggregate / crushed aggregate –those
obtained by mechanically crushing rocks, boulders, or
cobbles. Normally angular in shape and have rough
surface texture

9. CLASSIFICATION OF AGGREGATES
Based on Density:
• Based on specific gravity or density measured in
bulk, aggregate is divided into 3 types:
• Lightweight aggregate
• Normal-weight aggregate
• Heavyweight aggregate

10. NORMAL-WEIGHT AGGREGATE
• Crushed stone, gravel and ordinary sand are
examples of normal weight aggregate.
• They are commonly used in manufacture of
normal weight concrete, asphalt concrete
and roadway sub-base.
• The average values of sp.gr. For sand and
gravel are 2.6 and 2.65 respectively. Bulk
density of normal weight aggregate is around
1520 to 1680kg/m3.

11. LIGHTWEIGHT AGGREGATE
• Lightweight fine aggregate is any aggregate with
bulk density less than 1120kg/m3 and lightweight
coarse aggregate is any aggregate with bulk
density less than 880kg/m3.
• They are commonly used as ingredients in the
manufacture of lightweight concrete, for making
lightweight masonry blocks (to improved their
thermal and insulating properties and nailing
characteristic), and lightweight floor and roof slabs.
• 2 types of lightweight aggregate:
• Natural lightweight aggregates (eg: palm oil shell, rice husk,
etc)
• Manufactured (also called synthetic) lightweight
aggregates.

12. HEAVYWEIGHT AGGREGATE
• Those aggregate with high density and is used
primarily in the manufacture of heavyweight
concrete, employed for protection against nuclear
radiation and as bomb shelter.
• The unit weight of heavyweight concrete varies
from 2400kg/m3 with sp.gr range from 4.0 to 4.6.(eg:
mineral ores and barite)

13. PHYSICAL PROPERTIES OF
AGGREGATES
• Strength
• Hardness
• Toughness
• Durability
• Porosity
• Water absorption

14. STRENGTH OF AGGREGATES
• In practice, majority of normal aggregates are
considerably stronger than concrete
• A good average value of crushing strength of
aggregates is 200N/mm2.

15. HARDNESS OF AGGREGATES
• Hardness of aggregates is the ability of the
aggregate to withstand wear or load or
applied pressure.
• This hardness is depending on the type of
parent rock
• The test that can obtain the hardness is the
abrassion test.
• A satisfactory aggregate should have an
abrassion value of not more than 30% for
aggregates used for wearing surfaces and 50%
for aggregates used for non wearing surfaces.

16. TOUGHNESS
• Is the resistance of aggregate to failure by
impact.
• This can be determined by aggregate impact
test.
• The aggregate impact value shall not exceed
45% by weight for aggregate used for
concrete other than those used for wearing
surfaces and 30% for concrete for wearing
surfaces.

17. DURABILITY OF AGGREGATES
• Durability is ability of the aggregate to withstand
external or internal damaging attack or in other
words the soundness of aggregate.
• This can be obtained by carrying out the Soundness
test.

18. POROSITY
• Aggregate normally have pores of various
sizes.
• Aggregates will absorb water when it is dry
but normally release water in the concrete
mix when it is wet.
• The amount of water and its rate of
permeation depends on the size and volume
of aggregate
• Since the aggregate comprises 75% of the
concrete volume, it is essential to note that
porosity of an aggregate contribute to the
overall porosity of concrete.

19. TESTS ON AGGREGATES
a.Texture and shapes test
i.e. test for shapes of aggregates:
1. round shape –usually natural aggregates
2. irregular shape- a combination of different shapes
3. angular shape- usually of crushed stone
4. flaky shape- where the thickness is less than its length and
width
5. elongated- usually angular where its length is larger than
its width and thickness
6. flaky and elongated- its length is larger than its width and
its width is larger than its thickness.
• In terms of surface texture, the aggregates may have a
smooth texture, or coarse/rough texture or fissures or
porous.
• For production of concrete the aggregates which have
angular shape and coarse texture are recommended to
have high bond strength.

20. TESTS ON AGGREGATES (CONT’D)
• Strength tests
• Aggregates crushing strength
• Los Angeles abrasion test
• Aggregates Impact value test
• Ten percent fine test

21. TESTS ON AGGREGATES (CONT’D)
Physical properties:
• Specific gravity: usually 2.6 or 2.7
• Water absorption test: aggregates absorb water
because of their porosity.
• If all the pores are filled with water the
aggregates are said to be saturated and
surface dry.
• If all the water inside the pores are
removed by drying, the aggregates are
said to have maximum dry weight.

22. GRADING OF AGGREGATES:
• Coarse and fine aggregates to be used for
making concrete should be well graded.
Gradation means the particle size distribution of
aggregates. Test for grading of aggregates is
carried out using the sieve analysis method.

23. Sieve analysis test equipment

24. EXAMPLE OF SIEVE ANALYSIS OF
SAND
Sieve Mass Cumulative Mass %
Size retained mass retained passing passing
10 mm 0 0 287 100
5 mm 6 6 281 98
2.36 mm 17 23 264 92
1.18 mm 32 55 232 81
600mm 48 103 184 64
300mm 81 184 103 36
150mm 86 270 17 6
Pan 17 287 - -
287

25. A SIEVE ANALYSIS OF 250G OF SAND GIVES
THE
FOLLOWING RESULTS
Sieve size Mass retained
10 mm 0
5 mm 5
2.36 mm 31
1.18 mm 38
600mm 38
300mm 79
150m 51
Pan 8

26. M.S. 30- Typical grading of fine aggregates
% passing by weight
B.S. 410 Zone 2 Zone 3
Test Sieve
------------------------------------------------------
10.0 mm 100 100
5.0 90-100 90-100
2.36 75-100 85-100
1.18 55-90 75-100
600m 35-59 60-79
300m 8-30 12-40
150m 0-10 0-10

37. To calculate moisture content of Aggregates
Example:
A sample of damp aggregate weighing 2.35 kg is
dried by hair dryer until it just reaches the free-
running(saturated surface dry) condition. It is
then found to weigh 2.24 kg. After drying in the
oven at 110C to constant mass, it is found to
weigh 2.15 kg. Based on dry mass, calculate:
•free-water content
•the total water content

38. Solution:
a) Free-water content in aggregate is defined as the water content
when the aggregate is in saturated surface dry conditions.
i.e. initial weight = 2.35 kg
weight at SSD = 2.24 kg
free water content = 0.11 kg
% of free-water content based on dry mass
= 0.11/2.15 x 100 = 5.1%
b) Total water content = free-water content
+
water absorbed by aggregates
= 0.11 + (2.24 – 2.15)
= 0.2 kg
OR 2.35 – 2.15 = 0.2 kg
(i.e overall weight - wt of max. dry aggregates)
% of total water content based on dry mass,
= 0.2/2.15 x 100
= 9.3%

47. CLASSIFICATION
OF
AGGREGATES

48. DEPENDING UPON THE SIZE
OF THEIR PARTICLES
AGGREGATES ARE
CLASSIFIED AS:
(1) FINE AGGREGATES
(2) COARSE AGGREGATES

49. (1) FINE AGGREGATES:
Aggregates whose particles pass through 4.75 mm IS
sieve are termed as fine aggregates. Most commonly
used fine aggregates are sand (pit or quarry sand,
river sand and sea sand) and crushed stone in
powdered form, how ever some times sukhi and ash
or cinder are also used.
Jyoti Anischit 49

50. (A) SAND:
It consists of small angular or rounded grains of
silica depending upon the source from which
it is obtained. It is classified as:
50

51. (I) PIT OR QUARRY SAND:
It is found as deposited in soil and is to
be excavated out. Its grains are
generally sharp or angular. It should be
free from organic matter and clay. It is
usually considered to be the best fine
aggregate for use in mortar and
concrete.
51

52. (II) RIVER SAND:
IT IS OBTAINED FROM THE BANKS
AND BEDS OF RIVERS. IT MAY BE
FINE OR COARSE. FINE SAND
OBTAINED FROM BEDS AND BANKS
OF RIVERS IS OFTEN FOUND MIXED
WITH SILT AND CLAY SO IT
SHOULD BE WASHED BEFORE USE.
BUT COARSE SAND IS GENERALLY
CLEAN AND EXCELLENT FOR USE
ESPECIALLY FOR PLASTERING.
52

53. (iii) Sea Sand:
It consists of fine rounded grains of brown
colour and it is collected from sea shores or
sea beaches. Sea sand usually contains salts
and while using that in mortar, etc, causes
disintegration of the work in which it is used. In
R.C.C work these salts will attack
reinforcement if salt content is high. These salts
may cause efflorescence. It should be used
locally after thorough washing.
53

54. (b) Crushed stone:
It is obtained by crushing the waste stones of
quarries to the particular size of sand. Sand
obtained from by crushing a good quality
stone is excellent fine aggregate.
Mortar made with this sand is usually used in
ashlar work (good quality of work).
54

55. (2) COARSE AGGREGATES:
Aggregates whose particles
do not pass through 4.75 mm
IS are termed as coarse
aggregates. Most commonly
used coarse aggregates are
crushed stone, gravel; broken
pieces of burnt bricks,etc.
55

56. (A) CRUSHED STONE:
It is an excellent coarse aggregate and is
obtained by crushing granite, sand stone or
grained lime stone and all types of stones.
Crushed stones are used for the
construction of roads and railway tracks,
etc.
56

57. (b) Gravel:
It is an other very good coarse
aggregate. It is obtained from
river beds, quarries and sea
shores. The gravel obtained
from sea shores should be well
washed with fresh water
before use in order to remove
the impurities which may be
clay, salts ,silt,etc. It is
commonly used in the
preparation of concrete.
57

58. (c) Broken pieces of bricks:
It is also a good artificial source of
coarse aggregates. It is obtained by
breaking well burnt bricks. It is generally
used in lime concrete at places where
aggregates from natural sources are
either not available or are expensive. It
can be used at places where low
strength is required. It should be
watered well before using it in the
preparation of concrete. It is
commonly used for mass concrete in
foundations and under floors.
58

59. GOOD QUALITYIES OF AN IDEAL AGGREGATE:
An ideal aggregate used for the
manufacturing of concrete and mortar,
should meet the following requirements.
• (1) It should consist of natural stones, gravels
and sand or in various combinations of these
materials.
• (2) It should be hard, strong and durable.
59

60. • (3) It should be dense, clear and free from
any coating.
• (4) It should be free from injurious vegetable
matters.
• (5) It should not contain flaky (angular) and
elongated pieces.
• (6) It should not contain any material liable
to attack steel reinforcement in case of
reinforced concrete.
60

61. CHARACTERISTICS OF
AGGREGATES:
Important characteristics of aggregates
which influence the properties of resulting
concrete mix are discussed as under:
61

62. 1.COMPOSITION:
• Aggregate containing the constituents
which generally react with alkalies in
cement cause excessive expansion,
cracking of concrete mix, should never be
used. Suitability of aggregates should be
judged either by studying its service history
or by laboratory tests.
62

63. 2. SIZE AND SHAPE:
The size and shape of the aggregate
particles mainly influence the quantity of
cement required in a concrete mix and
ultimately economy of the concrete. For the
preparation of economical concrete, one
should use largest coarse aggregates
feasible for the structure.
63

64. Type of structure Max. size of aggregate
1. Mass concrete work 40 mm
i.e. dams, retaining walls,
piers and abutments, etc.
2. R.C.C work 20 mm
i.e. beams, columns, etc
3. Flooring 10 mm
It may be clearly noted that the size and
shape of the aggregate particles influence
the properties of freshly mixed concrete more
as compared to those of hardened concrete.
64

65. QUALITY TESTS OF
AGGREGATES:
There are so many tests which are to be
performed to check the quality of
aggregates but some important tests are
discussed below.
65

66. 1. CRUSHING TEST OF AGGREGATE:
The aggregate crushing value gives a
relative measure of resistance of an
aggregate to crushing under a gradually
applied compressive load. The aggregate
crushing strength value is useful factor to
know the behaviour of aggregates when
subjected to wear.
66

67. 2. IMPACT VALUE TEST:
The aggregate impact value gives a
relative measure of the resistance of an
aggregate to sudden shock or impact. The
impact value is some times used as an
alternative to its crushing value.
67

68. 3. ABRASION VALUE:
The aggregate abrasion
value gives a relative
measure of resistance of
an aggregate to wear
when it is rotated in a
cylinder along with some
abrasive charge.
68

69. SIEVE ANALYSIS:
In determination of the proportions of the
particles with in certain ranges in an
aggregate by separation on various sieves
of different size openings, may be defined
as sieve analysis.
69

70. FINENESS MODULUS (F.M):
The sum of cumulative percentage of
residues retained on each of the Indian
standard sieves
(80mm,40mm,20mm,10mm,4.75mm,2.36
mm,1.18mm,600 microns,300microns
and 150 microns each succeeding
sieve has half the aperture of the
previous one), divided by the 100,is
known as “Fineness modulus” of the
aggregates. The fineness modulus of an
aggregate is roughly proportional to the
average size of particles of the
aggregates.
70

71. (OR)
Index Number expressing the relative
sizes of both coarse and fine
aggregates is called “Fineness
Modulus”.
Sand Fineness Modulus
• Fine 2.2 to 2.6
• Medium 2.6 to 2.9
• Coarse 2.9 to 3.2
Note:
It is recommended that the fineness
modulus of sand should not be less
than 2.5 and should not be more than
3.0
71

72. STONE MASONRY
• The construction of stones bonded together with
mortar is termed as stone masonry where the
stones are available in a abundance in nature,
on cutting and dressing to the proper shape,
they provide an economical material for the
construction of various building components
such as walls, columns, footings, arches, lintels,
beams etc.

73. USES
1) Building foundations, walls, piers, pillars, and
architectural works.
2) Lintels, Beams, beams Arches, domes etc.,
3) Roofs and Roof coverings.
4) Cladding Works
5) Dams, light houses, monumental structures.
6) Paving jobs
7) Railway, ballast, black boards and electrical switch

74. SELECTION OF STONE FOR STONE
MASONRY:
1) Availability
2) Ease of working
3) Appearance
4) Strength and stability
5) Polishing characteristics
6) Economy
7) Durability

75. Through
Stone

78. GENERAL PRINCIPLES
• The stones to be used for stone masonry should
be hard, tough and durable.
• The pressure acting on stones should be vertical.
• The stones should be perfectly dressed as per
the requirements.
• The heads and bond stones should not be of a
dumb bell shape.
• In order to obtain uniform distribution of load,
under the ends of girders, roof trusses etc large
flat stones should be used

79. GENERAL PRINCIPLES
• The mortar to be used should be good quality
and in the specified faces.
• The construction work of stone masonry should
be raised uniformly.
• The plumb bob should be used to check the
verticality of erected wall.
• The stone masonry section should always be
designed to take compression and not the
tensile stresses.
• The masonry work should be properly cured after
the completion of work, for a period of 2 to 3
weeks.

80. • As far as possible broken stones or small stones
chips should not be used.
• Double scaffolding should be used for working at
higher level.
• The masonry hearting should be properly
packed with mortar and chips if necessary to
avoid hallows.
• The properly wetted stones should be used to
avoid mortar moisture being sucked.
General Principles

81. LAYING THE STONE
• Decrease the stone thickness from the bottom to the
top of wall.
• Ensure that the headers in the heart of the wall are
the same size as in the face and extend at least 12 in
(300 mm) into the core or backing. (Avoid Dumb-
bell shaped stones)
• Ensure that headers in “walls of 2 feet (600 mm) or
less in thickness” extend entirely through the wall. The
headers shall occupy at least 20 percent of the face
of the wall.

82. • Lay the masonry in roughly leveled courses. Ensure that the
bottom of the foundation is large, with selected stones.
• Lay the courses with leaning beds parallel to the natural bed
of the material.
• Regularly diminish the thicknesses of the courses, if varied, from
the bottom to the top of the wall. Keep a surplus supply of
stones at the site to select from.
• Before laying the stone in the wall, shape and dress it so that it
will not loosen after it is placed. No dressing or hammering
which will loosen the stone will be permitted after it is placed.
Laying The Stone

83. • Clean each stone and saturate it with water
before setting it. Clean and moisten the bed
that will receive it.
• Bed the stones in freshly made mortar with full
joints. Carefully settle the stones in place before
the mortar sets.
• Ensure that the joints and beds have an average
thickness of not more than 1 inch. (25 mm).
• Ensure that the vertical joints in each course
break with the adjoining courses at least 6 in.
(150 mm).

84. • If a stone is moved or if the joint is broken after
the mortar has set, take the stone up and
thoroughly clean the mortar from the bed and
joints. Reset the stone in fresh mortar.
• NOTE: Do not lay the masonry in freezing weather
or when the stone contains frost, except with
permission subjected to the required conditions.
• Whenever possible, properly point the face joints
before the mortar sets. If joints cannot be
pointed, rake them out to a depth of 1 in (25
mm) before the mortar sets.
• Do not smear the stone face surfaces with the
mortar forced out of the joints or the mortar used

85. • Thoroughly wet the joints pointed after the stone is
laid with clean water and fill with mortar.
• Drive the mortar into the joints and finish with an
approved pointing tool.
• Keep the wall wet while pointing. In hot or dry
weather, protect the pointed masonry from the sun
and keep it wet for at least three days after the
pointing is finished.
• NOTE: Do not perform pointing in freezing weather or
when the stone contains frost.
• After the pointing is completed and the mortar is set,
thoroughly clean the walls and leave them in a neat
condition.

87. Stone
a natural, hard substance formed from
minerals and earth material which are
present in rocks.
Rock
the portion of the earth’s crust having no
definite shape and structure

88. To qualify as a construction material, stone
should have the following qualities:

89. Strength: Most types of
stone have more than
adequate compressive
strength. The shear
strength of stone,
however, is usually
about 1/10 of its
compressive strength

90. Hardness: hardness is
important when stone
is used for flooring,
paving, and stair
treads.

91. Hardness:
Talc, easily scratched with the thumb-nail: 1
Gypsum, scratched by the thumb-nail: 2
Calcite, not scratched by thumb-nail but easily cut by knife: 3
Fluorite, can be cut by knife with greater difficulty than calcite: 4
Apatite, can be cut only with difficulty by knife: 5
Orthoclase, can be cut w/ knife w/ great difficulty on thin edges: 6
Quartz, not scratched by steel, scratches glass: 7
Topaz: 8
Sapphire: 9
Diamond: 10

92. Durability: Resistance
to the weathering
effects of rain, wind,
heat, and frost action
is necessary for
exterior stonework

93. Workability: A stone’s
hardness and grain
texture must allow it to
be quarried, cut and
shaped

94. Density: A stone’s
porosity affects its
ability to withstand
frost action and
staining

95. Density:
Porosity of Stones
24-hours Water Absorption of Stones by Volume

96. Appearance:
Appearance factors
include color, grain,
and texture

97. CLASSIFICATION OF STONES
(according to geological origin):
• Igneous rock
• Metamorphic rocks
• Sedimentary rock

98. Igneous rock is formed by the crystallization
of molten magma, as granite, obsidian and
malachite

99. Igneous rock also known
as primary, unstratified
or eruptive rocks

100. Metamorphic rocks has undergone a change
in structure, texture, or composition due to
the natural agencies, as heat and pressure,
especially when the rock becomes harder
and more crystalline, as marble and slate

101. Metamorphic rocks:
Examples of Transformation of Rocks

102. Sedimentary rock is formed by the deposition
of sediment by glacial action, as limestone,
sandstone and shale

103. Sedimentary rocks are also known as
aqueous or stratified rocks

104. As a load bearing wall material, stone is
similar to modular unit masonry. Although
stone masonry is not necessarily uniform in
size, its laid up with mortar and used in
compression. Almost all stone is adversely
affected by sudden changes in temperature
and should not be used where a high degree
of fire resistance is required.

105. Stone is used in construction in the following
forms:
• Rubble
• Dimension stone
• Flagstone
• Crushed stone

106. Rubble - consists of rough fragments of broken
stone that have at least one good face for
exposure in a wall.

107. Dimension stone - is quarried and squared stone
2’ or more in length and width and of specified
thickness, used commonly for wall panels,
cornices, copings, lintels and flooring.

108. Flagstone - refers to flat stone slabs used for
flooring and horizontal surfacing.

109. Crushed stone - is used as aggregate in concrete
products.