This document discusses different types of aggregates used in concrete based on their source, size, shape, and unit weight. It describes natural aggregates obtained from various rock types as well as artificial aggregates produced through chemical reactions or processing of natural aggregates. It also categorizes aggregates as fine, coarse, or all-in based on their size and discusses how aggregate properties like shape, surface texture, specific gravity, and shrinkage influence the properties of concrete.

5. 1 According to source or nature of
formation.
2 According to size .
3 According to shape.
4 According to unit weight.

6. • Natural Aggregates
• Artificial Aggregates

7. Main sources of these aggregate are natural deposits of
sand ,and gravel or obtained from quarries by cutting
rocks .the rocks are generally of three types i.e.
Igneous,Sedimentsary and Metamorphic rocks. The
aggregates obtained from Igneous rocks match the
requirements to a great extent. Also sedimentary rocks
provide good quality of aggregates but metamorphic
rocks are not used for aggregates because of formation
of thin structure which are not desirable.

8. These aggregates are generally
obtained from natural aggregates
by performing certain chemical
reactions , applying force,
heating the natural aggregates
etc. For example -broken bricks,
fly ash, blast- furnace slag etc.

9. •

10. Fine aggregates are those aggregates which
can pass through 4.75mm IS-sieve. For
example – Silts, clay, Loam etc. Fine
aggregates are natural sand , crushed stone
sand and crushed gravel stone . Fine
aggregates contribute towards reducing the
number of voids, increases the workability,
increases the volume, reduces the cost and
proper density is provided.

11. These are the aggregates which are the
residue of the 4.75 mm IS sieve and
passed through 75 mm IS sieve .Coarse
consists of crushed gravel, uncrushed
gravel and partially crushed gravel. These
aggregates are formed by natural
disintegration of rocks or by artificial
crushing of rocks or gravel.

12. All-in-aggregates are combine
mixture of fine aggregates and
coarse aggregates .It contains
various fractions of fine and
coarse aggregates. For High
quality concrete these type of
aggregates are used.

13. • Rounded Aggregates
• Irregular Aggregates
• Angular Aggregates
• Flaky and elongated Aggregates

14. In rounded aggregates less amount of
cement is required for preparing concrete
of good quality. There are 33% to 35%
voids in rounded aggregates .Due to
smooth and rounded structure there is
poor locking among or between the
aggregates and thus reducing strength of
structure but they provide high
workability.

15. These aggregates vary in surface as compared
to rounded aggregates. They are not perfect
ally round . They have 35 to 37%of voids.
Because of more surface area they required
more cemented paste. The interlocking
provided by these aggregate is not up to the
required level but better than rounded
aggregates.

16. These aggregates have angular structure i.e.
having shape and well defined edges, and are
rough particles. The voids percentage lies in the
range of 37 to 40 %.Due to rough and angular
structure the interlocking is quite good and also
required more cement paste for a workable
concrete with high strength. Crushed is an
example of angular aggregate.

17. The flaky aggregates are those in which the
least dimension of the aggregates is less than
3/5 the times the mean dimensions. Mean
dimensions the average size of sieves from
which the aggregates passes or on which they
are retained. The percentage of voids are
high for these aggregates.
Elongated can be define as those aggregates
which has its length or greatest dimension ,
greater than 9/5 of its mean dimension .

18. • Normal weight aggregates
(Sands ,gravel , crushes rocks etc.)
•Heavy weight aggregates
(Magnetite, scrap iron etc.)
•Light weight aggregates
(naturally manufactured )

19. •

20. Specific Gravity
Absolute: the ratio of the weight of the solid to the weight of an
equal volume of water (both at a stated temperature)
• refers to volume of the material excluding all pores
Apparent: ratio of the weight of the aggregate (dried in an oven at
212- 230ºF for 24 hours) to the weight of water occupying
a volume equal to that of the solid including the
impermeable pores
• volume of solid includes impermeable pores (but not
capillary pores)
Used for calculating yield of concrete or the quantity of aggregate required
for a given volume of concrete.

21. Particle Shape and Surface Texture
• Rough textured, angular, elongated particles require more water to
produce workable concrete than do smooth, rounded, compact
aggregates.
• Aggregates should be relatively free of flat and elongated particles
(limit to 15% by weight of total aggregate).
• Important for coarse and
crushed fine aggregate -
these require an increase in
mixing water and may affect
the strength of the concrete,
if cement water ratio is not
maintained.

22. Shrinkage of Aggregates:
Large Shrinkage = fine grained sandstones, slate,
basalt, trap rock, clay-
containing
Low Shrinkage = quartz, limestone,
granite, feldspar

23. • Flakiness test
• Abrasion test
• Crushing test
• Impact test