introduction Classification Of Aggregates, Good Qualities of an Ideal Aggregate: ,Tests on Aggregate:- , Specıfıc gravıty of Aggregate. , Flakiness & Elongation Index , Fineness Modulus (f.m):

1. AGGREGATE
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2. INTRODUCTION:-
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Aggregate are the important constituent in concrete. Aggregate are
granular material, derived from the most part from the natural
rocks, crushed stones, or natural gravels and sands.
Aggregate generally occupy about 70% to 80% of the volume of
concrete and can therefore be expected to have an important
influence on it properties.
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3. 3
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4. Classification Of Aggregates
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A) CLASSIFICATION BASED ON SIZE:
>Coarse aggregate:
Aggregate which retained on the No.4 (4.75mm) sieve. The
function of the coarse aggregate is to act as the main load-
bearing component of the concrete.
>Fine aggregate:
Aggregate passing No.4(4.75mm) sieve and
predominately retained on the No.200 (75µ) sieve. The fine
aggregate serve the purpose of filling all the open space in
between the coarse particles.
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5. B) Classification Based On Source:
>Natural aggregates:
This kind of aggregate is
taken from natural deposits without
changing their nature during the
process production such as crushing
and grinding.
>Manufactured (synthetics)
aggregates:
This is a kind of man-made
materials produced as a main product
or an industrial by-product. Some
example are blast furnace slag, air
cooled slag and broken bricks.
Synthetics aggregates are produced
by thermally processed materials
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6. C) Classification Based On Unit
Weight:
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 Aggregates are classified as Light-weight, Heavy-weight and
Normal-weight aggregate depending on weight and specific
gravity.
AGGREGA
TE
SPECIFIC
GRAVITY
UNIT
WEIGHT
(kN/m3)
BULK
DENSITY
(kN/m3)
EXAMPL
E
normal-
weight
2.5-2.7 23-26 15.20-16.80 sand
heavy-
weight
2.8-2.9 25-29 >20.80
Scrap
iron
light-weight 12 <11.20 dolomite
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7. D) CLASSIFICATION BASED ON SHAPE:
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 The shape of aggregates is an important characteristic, since it affect the
workability of concrete.
CLASSIFICATION EXAMPLE
Rounded River or seashore gravels
Partly rounded Pit sands & Gravels
Angular Crushed Rocks
Flaky Laminated rocks
FLAT ELONGATE
D
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8. E) Classification Based On Surface
Texture:
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 Surface texture is a measure of the smoothness and roughness of
aggregate. The grouping of aggregate is broad and is based on visual
examination of the specimen. As per IS:383-1970 the aggregates are
classified into five groups, namely, Glassy, Smooth, Granular, Crystalline,
Honeycombed and Porous.CLASSIFICATION EXAMPLES
Glassy Black flint
Smooth Gravel, Marble
Granular Sandstone
Rough Basalt
Crystalline Granite
Honeycombed & Porous Brick, slag
SMOOT
H
ROUG
H
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9. Good Qualities Of An Ideal Aggregate:
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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.
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.
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10. Tests On Aggregate:-
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The test usually conducted on coarse aggregates are
1. Aggregate Crushing Value
2. Aggregate Impact Value
3. Aggregate Abrasion Value
4. Particle Size
5. Flakiness &Elongation Index
6. Specific Gravity And Water Absorption
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11. 1) Impact Value Test
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1. 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.
2. Material passing 12.5mm and retained on 10mm sieve is
taken.
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12. 2) Aggregate Crushing Value:-
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1. The aggregate crushing value gives a relative measure of resistance of an
aggregate to crushing under a gradually applied compressive load.
2. The aggregate crushing strength value is useful factor to know the
behavior of aggregates when subjected to wear.
𝑪𝑹𝑼𝑺𝑯𝑰𝑵𝑮 𝑽𝑨𝑳𝑼𝑬 = 𝒘𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝒇𝒓𝒂𝒄𝒕𝒊𝒐𝒏 𝒑𝒂𝒔𝒔𝒊𝒏𝒈 𝒕𝒉𝒆 𝒔𝒊𝒆𝒗𝒆
𝒕𝒐𝒕𝒂𝒍 𝒘𝒆𝒊𝒈𝒉𝒕 𝒐𝒇 𝒔𝒂𝒎𝒑𝒍𝒆
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13. 3) Aggregate Abrasion Value:-
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 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
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14. 4) Sieve Analysis
 Sieve analysis is also called as Particle size
value.
 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.
𝐅𝐢𝐧𝐞𝐧𝐞𝐬𝐬 𝐌𝐨𝐝𝐮𝐥𝐮𝐬
=
cumulative % of agg retained on each sieve
𝟏𝟎𝟎
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16. Specıfıc Gravıty Of Aggregate.
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 Sp.Gr. is used in certain computations for concrete mix
design or control work, such as, absolute volume of aggregate
in concrete.
 It is not a measure of the quality of aggregate.
Sp.Gr.=
Weight of Agg. (WA)
Weight of an equal volume of water (VA*ρw)
=
WA
VA*ρw
=
ρA
ρw
Density of Agg.
Density of Water
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17. Flakiness & Elongation Index
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FLAKINESS INDEX= weight of particle passing through the
gauge
weight of sample
ELONGATION INDEX=weight of particle retained on length
gauge
weight of sample
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18. Fineness Modulus (F.M):
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 The sum of cumulative percentage of residues retained
on each of the Indian standard sieves (80mm, 40mm,
20mm, 10mm, 4.75mm, 2.36mm, 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.
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19. Thank you….19
THANK YOU
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