A presentation about Coarse Aggregate & Fine Aggregate on Civil Engineering subject. Due to privacy concern, only the group members names are kept where the student ID's are removed.

1. Aggregate

2. Abdull All Fuad
Pallob Sikdar
Rajib Roy
Md. Likhon Miah
Parvez Ahmed
Presented by,
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3.  Aggregate, in building and construction, material used for mixing with cement, bitumen, lime, gypsum, or
other adhesive to form concrete or mortar. The aggregate gives volume, stability, resistance to wear or
erosion, and other desired physical properties to the finished product.

5.  Aggregates occupy at least three quatres of
volume of concrete.
 Cheaper than the cement, put into the mix as
much as possible.
 Higher volume stability and better durability
than the cement paste alone.
 Do not react with cement and water.
Characteristics of Aggregates:

6. Classification of Aggregate:
Aggregates can be classified as following;
 Production Method
 Petrological Characteristics
 According to particle size
 According to their unit weight

7. Aggregates
Production Method Petrological
Characteristics
According to particle size According to their unit weight
Natural Aggregates
By-Product Aggregates
Igneous Rocks
Sedimentary Rocks
Metamorphic Rocks
Fine Aggregates
Coarse Aggregates
Normal Wright Aggregates
Light Weight Aggregates
Heavy Weight Aggregates

10. Depending on their particle size aggregates are classified as:
1. Fine Aggregate
2. Coarse Aggregate
Fig. Fine Aggregate Fig. Coarse Aggregate

11. Fine aggregates consist of natural sand or any crushed stone particles that
are ¼” or smaller. This product is often referred to as 1/4'” minus as it
refers to the size, or grading, of this particular aggregate.
Those particles that are predominantly retained on the 4.75 mm (No. 4)
sieve and will pass through 3-inch screen, are called coarse aggregate. The
coarser the aggregate, the more economical the mix.
Fine aggregates:
Coarse aggregate:

12. Properties of Fine Aggregates:
o Generally accounts for 30% - 35% of the mixture.
o It should be inert completely.
o Its grain should be sharp, strong and angular.
o It should not contain salts.
o The amount of silt and clay should not exceed 4%
o It should not be too fine.
o It should be well graded.
o Impurities like iron pyrites, acidic and basic salts,
mice etc should not present in the sand.

13. Properties of coarse aggregates:
• Maximum size would be ¾th of clear spacing between reinforcing bar or
between reinforcing bars and forms Makes up 40% - 45% of the
mixture.
• Shape of the particles of the C. A should be irregular and angular.
• Should not be elongated, flat and flaky because such particles are
considered as weak aggregates.
• Should have rough surface as it exhibit good bonding.
• Should have smaller porosity and absorption.
• Should not increase in volume because of moisture.
• Iron pyrites, coal, mica, shale, clay, alkali should be present in such
quantity that may not affect the strength and durability of concrete.

14. Tests of Aggregates:
◼ Flakiness index
◼ Elongation index
◼ Clay, Fine silt and Dust
◼ Organic Impurities
◼ Specific Gravity
◼ Bulk density and voids
◼ Crushing Value
◼ Impact value
◼ Abrasion value

15. Flakiness Index is the percentage by weight of particles in it, whose least dimension (i.e. thickness) is less than
three-fifths of its mean dimension. This test is used to determine the particle shape of the aggregate and each
particle shape being preferred under specific conditions.
Elongation Index is the percentage by weight of particles in it, whose largest dimension (i.e. length) is
greater than one and four-fifths times its mean dimension.
Flakiness index:
Elongation Index:
Fig. Flakiness Index Fig. Elongation Index

16. Clay, Fine silt and Dust Test:
This test is to find out the Silt content in sand.
To test for organic matter impurities in sand, shake some sand in a plain glass bottle with an equal volume of a 3%
solution of caustic soda (100 gm of caustic soda in 4 liters of water), and let this stand for 24 hours. The liquid
above the sand should not be darker than light straw (pale yellow) color. If the color is a marked yellow or brown,
high amount of organic impurities are present. These impurities can be removed by washing the sand, which also
helps to remove salts from the sand.
Organic Impurities:

17. The fine aggregate specific gravity test is used to calculate the specific gravity of a fine aggregate sample
by determining the ratio of the weight of a given volume of aggregate to the weight of an equal volume of
water.
Coarse aggregate crushing value is the percentage by weight of the crushed material obtained when test
aggregates are subjected to a specified load under standardized conditions. Aggregate crushing value is
a numerical index of the strength of the aggregate and it is used in construction of roads and pavements.
Specific Gravity Test:
Crushing Value:

18. The aggregate impact value gives a relative measure of the resistance of an aggregate to sudden shock or impact,
which in some aggregates differs from its resistance to a slow compressive load.
Abrasion test is carried out to test the hardness property of aggregates. The principle of Los Angeles abrasion test is
to find the percentage wear due to relative rubbing action between the aggregate and steel balls used as abrasive
charge.
Impact Value:
Abrasion Test:

19. Thank You