fine aggregates – river sand – crushed stone sand – properties – coarse Aggregates – Crushing strength – Impact strength – Flakiness Index – Elongation Index – Abrasion Resistance – Grading

1. AGGREGATES
E.PRABAKARAN
Assistant Professor,
Department of Civil Engineering,
Dr. N.G.P. Institute of Technology,
Coimbatore

2. Uses of Aggregates
• Concrete making
• Road laying
• Railway Ballast

3. Fine aggregate

5. Coarse aggregate:

6. • Classification
• Source
• Size
• shape
• Texture
• Strength
• Specific gravity and bulk density
• Moisture content
• Bulking factor
• cleanliness
• Soundness
• Chemical properties
• Thermal properties
• Durability
• Sieve analysis
• Grading

7. Classification
By size:
Fine aggregate:
• Sand and/or crushed stone
• < 5 mm (0.2 in.)
• F.A. content usually 35% to
45% by mass or volume of
total aggregate
Coarse Aggregate:
• Gravel and crushed stone
•  5 mm
• typically between 9.5 and
37.5 mm

8. By Weight
• Normal weight aggregates
• Natural – sand, gravel, crushed rock as granite etc.,
• Artificial – broken brick, air-cooled slag, etc.,
Produce normal-weight concrete 2200 to 2400 kg/m3
• Light weight aggregates – Shale, Clay, Slate, Slag
Produce structural lightweight concrete 1350 to 1850 kg/m3
Produce lightweight insulating concrete
• Heavy weight aggregates – Barite, Limonite, Magnetite, Ilmenite,
Hematite, Iron, Steel punchings or shot
Produce high-density concrete up to 6400 kg/m3

9. By source:
1. Minerals
• Silica
• Quartz, Opal
• Silicates
• Feldspar, Clay
• Carbonate
• Calcite, Dolomite
• Sulfate
• Gypsum, Anhydrite
• Iron sulfide
• Pyrite, Marcasite
• Iron oxide
• Magnetite, Hematite
2. Igneous rocks
• Granite
• Syenite
• Diorite
• Gabbro
• Peridotite
• Pegmatite
• Volcanic glass
• Felsite
• Basalt
3. Metamorphic rocks
• Marble
• Metaquartzite
• Slate
• Phyllite
• Schist
• Amphibolite
• Hornfels
• Gneiss
• Serpentinite
4. Sedimentary rocks
• Conglomerate
• Sandstone
• Claystone, siltstone,
argillite, and shale
• Carbonates
• Chert

10. Most common aggregates
• Sand
• Gravel
• Crushed stone

11. Size
• 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.
• >4.75 mm – coarse aggregate
• <4.75 mm – Fine aggregate

12. Range of Particle Sizes

13. •The maximum size of aggregate used in any given condition
may be limited by the following conditions:
• Thickness of section
• Spacing of reinforcement
• Clear cover
• Mixing, handling and placing techniques
• Rubbles – 60 cm thick – used to sink in plastic concrete – called
as displacement concrete – Koyna dam, Maharashtra
• For heavy reinforcement - <5mm aggregate used
• Generally in concrete – 20 mm as coarse aggregate, < 4.75 mm
as fine aggregate

14. • Maximum size ― is the smallest sieve that all of a particular
aggregate must pass through.
• Nominal maximum size ― is the standard sieve opening immediately
smaller than the smallest through which all of the aggregate must
pass.
• The nominal maximum-size sieve may retain 5% to 15%
 1/5 then narrowest dimension between sides of forms
 3/4 clear spacing between rebars and between rebars and the form
 1/3 depth of slabs

15. Shape:
• Affects workability
• Voids ratio – improve the water absorption

16. • Source: Concrete Technology, M.S.Shetty

17. • If the voids is 33 percent the angularity is zero
• If the voids is 44 percent the angularity number – 11
• The normal aggregate which are suitable for making the concrete may have
angularity number anything from zero to 11
• Angular aggregates are superior to rounded aggregates from the following two
points of view:
• Angular aggregates exhibits better interlocking effect
• Surface area is higher than rounded aggregate – for better bonding and strength

18. Texture:
• It is a measure of which depends upon the relative degree to which particle
surfaces are polished or dull; smooth or rough
• Deponds on:
• Hardness, grain size, pore structure, structure of the rock, and degree of forces acting on
the particle surface
• Surface smoothness increases, contact area decreases
• Rough textured aggregates develops higher bond strength in tension than
smooth textured aggregate.

19. • Source: Concrete Technology, M.S.Shetty

20. Measurement of surface texture
• Making a cast of the surface and magnifying a section of this
• Tracing the irregularities by drawing a fine point over the surface and
drawing a trace magnified by mechanical, optical or electrical means
• Getting section through the aggregates and examining

21. Strength:
• Theory and Scope
This is one of the major mechanical properties required for a road stone. The test
evaluates the ability of the aggregates used in road construction to withstand the
stresses induced by moving vehicles in the form of crushing. With this, the
aggregates should also provide sufficient resistance to crushing under the roller
during construction.
• Aggregate Crushing Value
The aggregate crushing value gives a relative measure of resistance of an
aggregate to crushing under a gradually applied compressive load. To achieve a
high quality of pavement, aggregate possessing low aggregate crushing value
should be preferred.

22. Apparatus
• A 15-cm diameter open-ended steel cylinder, with plunger and base-plate
• A straight metal tamping rod of circular cross-section 16 mm in diameter and 45 to 60 cm
long, rounded at one end
• A balance of capacity 3 kg
• IS Sieves of sizes 12.5, 10 and 2.36 mm
• Compression Testing Machine
• Cylindrical metal measure with 11.5 cm diameter
and 18 cm height

23. Procedure
• The sample passing 12.5 mm sieve and retained on 10 mm sieve is selected.
• The aggregate is tested in surface dry condition.
• The quantity of aggregate is such that the depth of material in the cylinder, after tamping is 10 cm.
• The cylindrical measure is filled in three layers of approximately equal depth, each layer being tamped 25
times with the rounded end of the tamping rod and finally leveled off, using the tamping rod as a straight
edge.
• The weight of the material comprising the test sample is determined.
• The cylinder of the test apparatus is put in position on the base-plate and the test sample added in thirds,
each third being subjected to 25 strokes from the tamping rod.
• The surface of the aggregate is carefully levelled and the plunger inserted so that it rests horizontally on this
surface, care being taken to ensure that the plunger does not jam in the cylinder.
• The apparatus, with the test sample and plunger in position, is placed between the platens of the testing
machine and loaded at as uniform a rate as possible so that the total load is reached in 10 minutes. The total
load is 40 tonnes.
• The load is released and the whole of the material removed from the cylinder and sieved on a 2.36-mm IS
Sieve.
• The fraction passing the sieve is weighed

24. Observation:
• Nominal size of the aggregate =
S.No.
Weight of
the empty
measure (g)
Weight of the
measure with
aggregate (g)
Weight of
aggregate
(g)
Weight of
aggregate
retained
on 2.36
mm sieve
(g)
Weight of
aggregate
passing
through
2.36 mm
sieve (g)
Aggregate
Crushing
Strength (%)
Average

25. Calculation
Weight of the aggregate = Weight of measure with aggregate – Weight of the
empty measure
Weight of aggregate passing through
2.36 mm sieve
Aggregate Crushing Strength = ------------------------------------------ x 100
Weight of aggregate taken

26. Result
• The Crushing strength of the given sample of coarse aggregate is
_______________%
Specification as per IS : 383 – 1970
• The aggregate crushing value should not exceed 45% by weight for
aggregates used for concrete other than for wearing surfaces and 30% by
weight for concrete for wearing surfaces, such as runways, roads and
pavements.

27. Aggregate Impact Value
• The aggregate Impact value gives a relative measure of the resistance of an
aggregate to sudden shock or impact.
Apparatus
• Impact testing machine
• A cylindrical steel cup of internal diameter 102 mm and
depth 50mm
• IS Sieves of sizes 12.5, 10 and 2.36 mm
• A cylindrical metal measure of internal diameter 75 mm and
depth 50 mm
• Tamping rod of 10 mm diameter and 230 mm long, rounded at
one end
• Balance

28. Procedure
• The test sample consists of aggregates passing 12.5mm sieve and retained on 10mm sieve.
• The aggregate comprising the test sample is dried in an oven for a period of four hours at a
temperature of 100 to 110°C and cooled.
• The measure is filled with the aggregate in three layers and each layer tamped with 25 strokes
of the rounded end of the tamping rod.
• After the third layer is tamped, the surplus aggregate struck off, using the tamping rod as a
straight-edge.
• The net weight of aggregate in the measure is determined
• The whole of the test sample is placed in the steel cup, which is fixed firmly in position on the
base of the machine and compacted by a single tamping of 25 strokes of the tamping rod.
• The hammer is raised until its lower face is 380 mm above the upper surface of the aggregate
in the cup and allowed to fall freely on to the aggregate.
• The test sample is subjected to a total of 15 blows each being delivered at an interval of not
less than one second.
• The crushed aggregate is removed from the cup and is sieved on the 2.36-mm IS Sieve.
• The fraction passing the sieve is weighed.
• The fraction retained on the sieve is also weighed and if the total weight is less than the initial
weight by more than one gram, the result is discarded and a fresh test made. Two tests are
made.

29. Observation
• Nominal size of the aggregate =
• Calculation
Weight of the aggregate = Weight of measure with aggregate – Weight of the empty Measure
Weight of aggregate passing through 2.36 mm sieve
Aggregate Impact Strength = _________________________________________ X 100
Weight of aggregate taken
S.No. Weight of the
empty
measure (g)
Weight of the
measure with
aggregate (g)
Weight of
aggregate (g)
Weight of
aggregate
retained on
2.36 mm
sieve (g)
Weight of
aggregate
passing
through 2.36
mm sieve (g)
Aggregate
Impact Strength
(%)
Average

30. Result
• The Impact strength of the given sample of coarse aggregate is
_______________%
• Specification as per IS: 383 – 1970
The aggregate impact value should not exceed 45% by weight for aggregates
used for concrete other than for wearing surfaces and 30% by weight for
concrete for wearing surfaces, such as runways, roads and pavements.

31. AGGREGATE ABRASION VALUE
Theory and Scope
Abrasion is a measure of resistance to wear. It is an essential property for road aggregates
especially when used in wearing coarse. Due to the movements of traffic, the road stones used in
the surfacing course are subjected to wearing actions at the top. When traffic moves on the road,
the soil particles (sand) which come between the wheel and road surface causes abrasion on the
road stone.
Los Angeles Abrasion Test
The principle of Los Angeles abrasion test is to find the percentage wear due to the relative
rubbing action between the aggregates and steel balls used as abrasive charge.
Apparatus
• Los Angeles abrasion testing machine
• Set of IS sieves

32. Observation
• Nominal size of the aggregate =
S.No.
Weight of
Aggregate taken
for testing (g)
Weight of aggregate
retained on 1.70
mm sieve (g)
Weight of aggregate
passing through
1.70 mm sieve (g)
Aggregate
Abrasion Value
(%)
Average

33. Procedure
• The test sample consists of clean aggregate which has been dried in an oven at 105 to 110°C to
substantially constant weight and shall conform to one of the gradings.
• The test sample and the abrasive charge shall be placed in the Los Angeles abrasion testing machine
• The machine shall be rotated at a speed of 20 to 33 rev/min. For gradings A, B, C and D, the machine
shall be rotated for 500 revolutions; for gradings E, F and G, it shall be rotated for 1000 revolutions.
• At the completion of the test, the material shall be discharged from the machine and a preliminary
separation of the sample made on a sieve coarser than the l.70 mm IS Sieve.
• The material coarser than the 1.70 mm IS Sieve shall be washed and dried in an oven at 105 to 110°C to
a substantially constant weight, and accurately weighed to the nearest gram.
• The difference between the original weight and the final weight of the test sample shall be expressed as
a percentage of the original weight of the test sample. This value shall be reported as the percentage of
wear.
• Result
• The abrasion value of the given sample of coarse aggregate is ________________%
• Specification as per IS : 383 – 1970
• The aggregate abrasive value should not exceed 50% by weight for aggregates used for concrete other
than for wearing surfaces and 30% by weight for concrete for wearing surfaces, such as runways, roads
and pavements.

34. Specific Gravity
FOR FINE AGGREGATE:
Specific gravity of aggregates is made use of in design calculations of
concrete mixes.
APPARATUS:
• PYCNOMETER.
• BALANCE(0.1G SENSITIVITY)
• DISTILLED WATER.
Procedure:
• The pycnometer is thoroughly cleaned and dried, its empty weight is taken (W1) gms
• Take about 150g (approximately) of dry sand & put it the bottle and find its weight (W2)
gms
• The density bottle is now filled with distilled water upto the mark(marked in bottle) and
weigh as (W3) gms
• The bottle is now emptied, completely fill with only distilled water the mark and find its
weight(W4)gms

35. • CALCULATION:
SPECIFIC GRAVITY OF SOIL (G) = [(W2 – W1)] / [(W2 -W1) – (W3-W4) ]
• RESULT:
SOIL SPECIFIC GRAVITY OF SOIL (G) = _________
SL.NO PARTICULARS WEIGHT IN GRAMS
TRIAL 1
WEIGHT IN
GRAMS
TRIAL 2
WEIGHT IN
GRAMS
TRIAL 3
1 WEIGHT OF PYCNOMETER (W1)
2 WEIGHT OF PYCNOMETER + SOIL (W2)
3 WEIGHT OF PYCNOMETER + SOIL +
WATER (W3)
4 WEIGHT OF PYCNOMETER + WATER
(W4)

36. • For Coarse aggregate:
• There are three methods of testing for the determination of the specific gravity of aggregates, according
to the size of the aggregates larger than 10 mm, 40 mm and smaller than 10 mm. For Samples larger
than 10 mm, 40 mm, the below given test method is used and for samples smaller than 10 mm
Pycnometer test is done.
Apparatus Required
• A balance of capacity about 3kg, to weigh accurate 0.5g, and of such a type and shape as to permit
weighing of the sample container when suspended in water.
• A thermostatically controlled oven to maintain temperature at 100-110° C.
• A wire basket of not more than 6.3 mm mesh or a perforated container
of convenient size with thin wire hangers for suspending it from the balance.
• A container for filling water and suspending the basket
• An air tight container of capacity similar to that of the basket
• A shallow tray and two absorbent clothes, each not less than 75x45cm.

37. • Procedure
• About 2 kg of aggregate sample is washed thoroughly to remove fines, drained and placed
in wire basket and immersed in distilled water at a temperature between 22- 32º C and a
cover of at least 5cm of water above the top of basket.
• Immediately after immersion the entrapped air is removed from the sample by lifting the
basket containing it 25 mm above the base of the tank and allowing it to drop at the rate of
about one drop per second. The basket and aggregate should remain completely immersed
in water for a period of 24 hour afterwards.
• The basket and the sample are weighed while suspended in water at a temperature of 22°
– 32°C. The weight while suspended in water is noted = W1g.
• The basket and aggregates are removed from water and allowed to drain for a few
minutes, after which the aggregates are transferred to the dry absorbent clothes. The
empty basket is then returned to the tank of water jolted 25 times and weighed in
water= W2 g.
• The aggregates placed on the absorbent clothes are surface dried till no further moisture
could be removed by this cloth. Then the aggregates are transferred to the second dry
cloth spread in single layer and allowed to dry for at least 10 minutes until the aggregates
are completely surface dry. The surface dried aggregate is then weighed = W3 g
• The aggregate is placed in a shallow tray and kept in an oven maintained at a temperature
of 110° C for 24 hrs. It is then removed from the oven, cooled in an air tight container and
weighted=W4 g.

38. Observations of Test
Weight of saturated aggregate suspended in water with basket = W1g
Weight of basket suspended in water = W2 g
Weight of saturated surface dry aggregate in air = W3g
Weight of oven dry aggregate = W4 g
Weight of saturated aggregate in water = W1 – W2 g
Weight of water equal to the volume of the aggregate = W3–( W1–W2)g
• Formulas:
(1) Specific gravity = W3 / (W3– (W1– W2))
(2) Apparent specific gravity = W4/ (W4– (W11– W2))
(3) Water Absorption = ((W3 – W4) / W4) X 100
** The size of the aggregate and whether it has been artificially heated
should be indicated.
** Though high specific gravity is considered as an indication of high
strength, it is not possible to judge the suitability of a sample aggregate
without finding the mechanical properties such as aggregate crushing, impact

39. Recommended Values of Specific Gravity and Water Absorption for
Aggregates
The specific gravity of aggregates normally used in road construction ranges
from about 2.5 to 3.0 with an average of about 2.68.
Water absorption shall not be more than 0.6 per unit by weight.

40. Grading:
• Aggregate comprises about 55% of the volume of mortar and about 85% volume of mass of
concrete. Mortar contains aggregate size of 4.75 mm and concrete contains aggregate upto a
maximum size of 150 mm
• Workable concrete can be attain with good grading of aggregate which leads for minimum
voids and maximum strength
• Sieve analysis:
• The aggregates used for making concrete are normally of the maximum size 80 mm, 40
mm, 20 mm, 10 mm, 4.75 mm, 2.36 mm, 600 micron, 300 micron and 150 micron.
• The aggregate fraction from 80 mm to 4.75 mm are termed as coarse aggregate and those
fractions from 4.75 mm to
150 micron are termed as fine
aggregate

41. Minimum weight of sample for sieve analysis (IS 2386 Part 1 – 1963)

42. Fineness Modulus (FM)
• A single number system used to express the fineness or coarseness of
an aggregate
• Higher values indicate coarser grading
• Sum of cumulative % retained on the standard sieves
• Certain sieves are NOT counted (even if used)
• Can be helpful in calculating blends of two materials
• FM of coarse aggregate can also be calculated and can aid in blending
coarse and medium size materials

43. • Take suitable quantity (1000 gms) of oven dried soil retained in 75sieve.
• Sieve the soil through 4.75 mm, 2.36 mm, 1.18 mm, 0.71mm,600 , 500,
300, 150 using a mechanical shaker for 5 minutes.
• Each sieve and pan with soil retained on them is weighted carefully and note it
in the observation.
• The sum of the retained soil is checked against the original mass of soil taken.
• All the observations are entered in the data sheet and the calculations are
made.
• By using the formula find the uniformly co-efficient, coefficient of
curvature from semi log graph.
• Fineness modulus = Total sum of the cumulative % retained / 1000

44. Dry Sample Wt. 1267 g
Sample:
Retained
Sieve Size, (mm) Sieve Size, (US) Mass, (g) Ind. % Retained Cum % Retained % Passing
150 1 1/2" 0 0 0 100
75 1" 0 0 0 100
37.5 3/4" 0 0 0 100
19 1/2" 0 0 0 100
9.5 3/8 0 0 0 100
4.75 # 4 25 2.0 2.0 98.0
2.36 # 8 163 12.9 14.9 85.1
1.18 #16 228 18.0 32.9 67.1
0.6 # 30 278 22.0 54.9 45.1
0.3 # 50 355 28.1 83.0 17.0
0.15 # 100 177 14.0 97.0 3.0
Pan Pan 38 3.0
Total 1264 100 2.85 FM
Sieve Loss Check 0.24%
Gradation & Fineness Modulus:
100 - 2 = 98
100 - 14.9 = 85.1

45. Flakiness
Flakiness and Elongation tests are conducted on coarse aggregates to assess the shape of the aggregates. Aggregates which
are flaky or elongated are detrimental to the higher workability and stability of mixes. They are not conducive to good
interlocking and hence the mixes with an excess of such particles are difficult to compact to the required degree.
FLAKINESS INDEX
The flakiness index of aggregates is the percentage by particles whose least dimension (thickness) is less than 3/5th (0.6) of
their mean dimension. The test is not applicable to sizes smaller than 6.3mm.
Apparatus
• Thickness gauge
• I.S. sieves of sizes 63, 50, 40, 31.5, 25, 20, 16, 12.5, 10 and 6.3mm
• Balance
Procedure
• The sample is sieved with the set of sieves arranged in order
• A quantity of aggregate is taken sufficient to provide the minimum number of 200 pieces of any fraction to be tested
• Each fraction is gauged in turn for thickness on the metal gauge
• The total amount passing the gauge is weighed to an accuracy of atleast 0.1 percent of the weight of the test sample.
• The flakiness index is calculated as the total weight of the material passing the various thickness gauges expressed as a
percentage of the total weight of the sample gauged
Result
The Flakiness Index of the given sample of coarse aggregates is ________%

46. Observation
• Nominal size of the aggregate =
Weight of aggregate retained in Elongation gauge
Elongation Index = ________________________________________________ * 100
Weight of aggregate taken for testing
Size of Aggregate
Weight of the aggregate
taken (g)
Weight of aggregates
Passing through Thickness
gauge (g)
Passing through I.S.
Sieve
(mm)
Retained on I.S.
Sieve (mm)
63 50
50 40
40 31.5
31.5 25
25 20
20 16
16 12.5
12.5 10.0
10 6.3
Total

47. Elongation test:
Elongation Index
• The elongation index of an aggregate is the percentage by weight of particles
whose greatest dimension (length) is greater than 1 and 4/5th times (1.8 times)
their mean dimensions. The elongation test is not applicable to sizes smaller
than 6.3mm.
Apparatus
• Elongation gauge
• I.S. sieves of sizes 63, 50, 40, 31.5, 25, 20,
16, 12.5, 10 and 6.3mm
• Balance

48. Procedure
• The sample is sieved with the set of sieves
arranged in order
• A quantity of aggregate is taken sufficient to
provide the minimum number of 200 pieces
of any fraction to be tested
• Each fraction is gauged individually for
length on the metal gauge
• The total amount retained by the length
gauge is weighed to an accuracy of
atleast 0.1 percent of the weight of the test
sample
• The elongation index is calculated as
the total weight of the material retained
on the various length gauges, expressed as a
percentage of the total weight of the sample
gauged.

49. Observation
• Nominal size of the aggregate =
Calculation
Weight of aggregate retained in Elongation gauge
Elongation Index = ________________________________________________ * 100
Weight of aggregate taken for testing
Result
Size of Aggregate Weight of the aggregate taken
(g) Weight of aggregates Retained in
Elongation gauge (g)Passing through I.S. Sieve
(mm)
Retained on I.S. Sieve
(mm)
63 50
50 40
40 31.5
31.5 25
25 20
20 16
16 12.5
12.5 10.0
10 6.3
Total

50. Mineral
Composition
Particle
Shape
Surface
Characteristics
Gradation Soundness Chemical
Activity
Physical
Properties
Specific
Gravity
Hardness
Thermal
Properties
Absorption
Elastic
Properties
Cement
Solutions
Deleterious
Minerals
Uniformity
Flat
Elongated
Angular
Round
StoneGravel
Coatings
Roughness
Bond to
Mortar
Freezing
and
Thawing
Workability and
Water Requirement
of Cement
Cement Content
Proportions
Fine Coarse
Salts
Artificial
Aggregate
Maximum
Size
Toughness
Wear
Permeability
Coarse Aggregate

51. Mineral
Composition
Particle
Shape
Surface
Characteristics
Organic
Impurities
Gradation Soundness Chemical
Activity
Physical
Properties
Specific
Gravity
Hardness
Thermal
Properties
Absorption
Elastic
Properties
Cement
Solutions
Water
Reten-
tivity
Deleterious
Minerals
Uniformity
Flat
Elongated
Angular
Round
Manufac-
tured Bond
Natural
Band
Coatings
Roughness
Bond to
Paste
Freezing
and
Thawing
Workability and
Water Requirement
of Concrete
Cement Content
Proportions
Fine Coarse
Salt
Fine Aggregate

52. Seminar topics:
• Bulking of aggregates
• Alkali aggregate reaction

53. References
• M.S.Shetty, Concrete Technology, S.Chand and company Ltd., New
Delhi, 2005
• http://www.iricen.gov.in/LAB/res/pdf/test-19.pdf
• https://theconstructor.org/building/aggregates-specific-gravity-
water-absorption-test/1358/
• https://www.slideshare.net/