Building materials notes

1. 1
Lecture Slides
Department of Civil Engineering
Vel Tech
Building Materials
( Subject Code: )

2. UNIT III AGGREGATES and CONCRETE
Aggerates-Fine aggregates-River sand-M sand – P sand –
Properties- Coarse aggregates- Properties- Grading- Tests on coarse
aggrates- recycled aggregates- concrete- Ingredients- Grades- Types
– Manufacturing process- Application of concrete- Admixture- Self-
healing concrete – light generating concrete.
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Syllabus

3. Introduction
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Aggregates 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.

4. Classification of Aggregates
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
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.
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
such as expanded clay and shale used for making light weight concrete.
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5. Classification of Aggregates
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Based on Shape:
The shape of aggregates is an important characteristic, since it affect the
of concrete.
CLASSIFICATION EXAMPLE
Rounded River or seashore gravels
Partly rounded Pit sands & Gravels
Angular Crushed Rocks
Flaky Laminated rocks

6. Fine Aggregates
Fine aggregates
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.
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Sand it consist of small angular or rounded grains of silica depending upon the source from which it is
obtained. It is classified as:
Pit or Quarry sand: 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. (i) Pit or quarry sand:
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.
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.
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).

7. M-sand
• What is M-sand
• Manufactured sand is a substitute of river for
construction purposes sand produced from
hard granite stone by crushing. The crushed
sand is of cubical shape with grounded edges,
washed and graded to as a construction
material. The size of manufactured sand (M-
Sand) is less than 4.75mm. And it is also called
as ‘ROBO SAND’
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8. Why Manufactured sand is used !
• Manufactured sand is an alternative
for river sand.
• Having more good quality than the
river sand.
• Availability and transportation of M
sand.
• Cost of construction is less by using
this sand
• It is well graded in the required
proportion.
• Absorption of water by M sand is
very less.
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9. Properties of M-sand
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• High strength of concrete.
• Durability of concrete.
• Workability of concrete.
• Less Construction Defects.
• Economy.
• Eco-friendly.

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11. Manufacturing of M- sand
 Primary Crushing
The raw mined material is brought to the crusher plant by rear-dump haulers or front-
end loaders. Primary crushing reduces this run of mine rock to a more manageable size.
The two types of primary crushers are the compression (jaw crushers and gyratory
crushers).
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12. Manufacturing of M - Sand
Secondary crushing
The Secondary crushing unit is basically the same as the primary crusher except it
reduces the stone to an even smaller size. It consists of a reciprocating feed hopper,
an over crusher conveyor, a two-deck vibrating screen, a compression crusher, an
under crusher return conveyor, a revolving elevator wheel, a diesel power unit, and
conveyors.
There are three types crushers. They are :-
1. Cone crusher
2. 2. Roll crusher
3. 3. Hammer mill
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Cone Crusher

13. Manufacturing of M-Sand
Vertical Shaft Impactor (VSI) Working principle of vertical shaft impactor is totally different than
horizontal shaft impactor. It has a high speed rotor with wearing resistant tips and main
chamber (crushing chamber) is designed in such a way so that speed rotor throw the rocks
against the high crushing chamber. In vertical shaft impactor crusher predominant force is the
velocity of speed rotor.
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VSI VSI

14. Manufacturing of M sand
Horizontal shaft impactor (HSI) Horizontal shaft impactor (HSI) crusher consists of hammers that
are fixed to the spinning rotor. Hammers are utilized for the breaking of these rocks.
horizontal shaft impactor crusher is used for soft materials and materials like gypsum,
phosphate, limestone and weathered shales.
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15. Manufacturing of M sand
Screen are essential to the final aggregate product. The right screen selection will allow
uninterrupted production of aggregate. Screens separate crushed rock into two or more
particle size ranges. Screens are also used to remove oversized rock before they get into
the secondary hopper and to separate out very small particles, also known as fines.
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16. P-sand
The full form of P sand is Plastering Manufactured Sand which is also known as
crushed sand or manufactured fine aggregate. This type of sand is used in construction
greatly. They are a very fine grade of sand used mainly for plastering and creating
renders. They give a very smooth finish to the plasters.
 Properties of P sand
P-Sand is free of silt and clay particles and therefore has denser particle packing
properties compared to natural/river sand. It also offers
higher flexural strength,
better abrasion resistance,
higher unit weight, and
lower permeability.
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17. Coarse aggregates:
Coarse aggregates are any particles greater than 4.75 mm, but generally range between 6 and 32 mm in size. Gravels
constitute the majority of coarse aggregate used in concrete with crushed stone
Coarse aggregates - Properties
 Aggregate must be strong and hard enough to resist the crushing action.
They should not have the cover of organic materials, clay, and dust otherwise it will affect the bonding
strength of concrete and aggregate.
 The aggregates used for concrete must be durable.
 Coarse aggregates for concrete should be chemically inactive.
 They should not contain an excessive amount of angular, sharp, and hard particles.
 The aggregate shape should be ideally spherical or cubical.
 They should be free from any hygroscopic slat.
 Aggregates should not have water absorption of more than 5% of their actual weight.
 The ideal size of coarse aggregates should be such that they should pass the through IS 63 mm sieve
and retains on the 4.75 mm IS sieve.
Aggregate used for construction must be free from any disintegrated pieces, alkalis, vegetable matter,
etc.
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18. Grading of Coarse aggregates:
The coarse aggregate used in making concrete contains aggregates of different sizes. This
particle size distribution of the aggregate is termed “Gradation”. The sieve analysis was
conducted to determine this particle size distribution.
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19. Grading of Coarse aggregates:
1. Well graded
 Well-graded aggregates have a gradation of particle size that fairly evenly
spans the size from the finest to the coarsest. A core of well-graded aggregate
concrete shoes a packed field of many different particle sizes.
2. Poor Graded
 This aggregate is characterized by a small variation in size. It includes
aggregate particles that are near the same size. This means that the particles
of the aggregate pack together, leaving relatively large voids in the concrete.
3. Gap Graded
 Gap-graded aggregate consists of aggregate particles in which some
intermediate-size particles are missing. A core of gap-graded concrete shows
a field of small-seized aggregate interspersed with slightly large aggregate
pieces embedded in a small-sized aggregate.
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20. Test on Coarse Aggregates
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21. Test on Coarse Aggregates
 1. Impact Test on Aggregates.
 2. Crushing Value Test of Aggregate.
 3. Abrasion Test Of Aggregate.
 4. Shape Test on Aggregates (Elongation & Flakiness Index).
 5. Specific Gravity and Water Absorption Test of Coarse
Aggregate.
 6. Soundness Test on Aggregates.
 7. Bitumen Adhesion Test.
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22. Impact Test on Aggregates
 It is the ability of aggregates that resist sudden impact or shock load on it. Also, it can
be defined as the resistance of an aggregate to failure by impact load is known as
the Impact Value of Aggregate.
 The need for impact value test is used to measure the toughness of aggregates which is
nothing but the ability of aggregates to resist sudden loading or impact loading
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 Aggregate Crushing Value is the relative resistance of aggregates to crushing under
gradually applied compressive load.
 Aggregate Crushing Value Test is an important test to be performed on aggregate. The
strength of aggregate parent rock is determined by preparing cylindrical shape specimens of
size 25 mm diameter and 25 mm height.
IS Code For Crushing Value Test
 Aggregate Crushing value test IS Code is 2386-4 (1963): Methods of Test for Aggregates for
Concrete.
Crushing Value Test of Aggregate

24. Abrasion Test Of Aggregate
 The abrasion Test is the measure of aggregate
toughness and abrasion resistance such as
crushing, degradation, and disintegration.
 This test is suggested by AASHTO T 96 or ASTM C
131: Resistance to Degradation of Small-Size
Coarse Aggregate by Abrasion and Impact in Los
Angeles Machine.
 IS Code For Abrasion Test of Aggregate Test
 The Abrasion test of aggregate is done as per IS
2386.4 – 1963: Method of Testing For Coarse
Aggregate
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25. Shape Test on Aggregates (Elongation & Flakiness Index)
Flakiness and Elongation Index Tests are very important tests to be performed on
aggregate in the laboratory. This test gives the percentage of the flaky and elongated
aggregate present in the total aggregate sample.
 Flakiness Index
The flakiness index of aggregate is the % by weight of the particles (aggregates) whose
thickness is less than 3/5th(0.6 times) of their mean dimension.”
 Elongation Index
The Elongation index of aggregate is the % by weight of the particles (aggregates) whose
length is greater than 1 and 4/5th (1.8 times) of their mean dimension.”
 IS Code For Test
 The elongation and Flakiness Index Test is conducted as per IS 2386 (Part 1) – 1963
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26. Specific Gravity and Water Absorption Test of Coarse Aggregate
Specific gravity and Water Absorption Tests of Aggregates are major
important tests to be performed on aggregate.
These two parameters or properties of aggregate play an important role in
the mix design of concrete. As we know that aggregate occupies 70 to 80%
volume of concrete, and its testing becomes essential before use.
Specific Gravity
Specific Gravity is defined as the ratio of the weight of a given volume
of aggregate to the weight of an equal volume of water. The specific gravity
usually showed the strength and quality of the material. The specific gravity
of aggregates test is usually used for the identification of stones or
aggregates.
Water Absorption
Water absorption of aggregates is the % of water absorbed by an air-
dried aggregate when immersed in water at 27°C for a period of 24 hours.
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27. Soundness Test on Aggregates
 The soundness of aggregate refers to the durability of an aggregate in terms of the
resistance to the action of weather and is an indication of the resistance to weathering
of fine and coarse aggregates.
 This test, estimates the resistance of an aggregate to in-service weathering. It can be
performed on both coarse and fine aggregate.
 Soundness is the % loss of material from an aggregate blend during the sodium or
magnesium sulphate soundness test
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28. Bitumen Adhesion Test
 The adhesion between mineral aggregates and bitumen is an important criterion that
describes the quality of the asphalt mixture, asphalt pavement performance, and
resistance to distress. The lack of bonding can lead to significant asphalt pavement
damage.
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29. Recycled aggregate
Recycled aggregates are developed from the reprocessing of materials that
have been originally used in construction. They include sand, gravel, crushed
stone, and asphalt. Essentially, the term refers to materials that have been
previously used in construction.
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30. Properties of recycled aggregates
 Generally, recycled aggregate, in comparison to the aggregate obtained from
natural resources,
Is characterized by:
 higher water absorption,
 lower density,
 higher content of organic.
 possibly harmful substances,
 higher level of crushability,
 reduced abrasion resistance
 reduced resistance to frost
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31. Concrete
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concrete is a mixture of paste and aggregates. The paste, composed of portland cement and water,
coats the surface of the fine and coarse aggregates. Through a chemical reaction called hydration,
the paste hardens and gains strength to form the rock-like mass known as concrete.

32. Ingredients of Concrete
Concrete is a mixture of cement, air, water, sand, and gravel–it's as simple as that! Not exactly. The typical
concrete mix is made up of roughly 10% cement, 20% air and water, 30% sand, and 40% gravel. This is called
the 10-20-30-40 Rule–though proportions may vary depending on the type of cement and other factors
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33. Grades of Concrete :As per IS 456:200
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34. Types of concrete
 Normal Strength Concrete
 Plain or Ordinary Concrete
 Reinforced Concrete
 Prestressed Concrete
 Precast Concrete
 Light – Weight Concrete
 High-Density Concrete
 Air Entrained Concrete
 Ready Mix Concrete
 Polymer Concrete
 Polymer cement concrete
 Polymer impregnated
concrete
 High-Strength Concrete
 High-Performance Concrete
 Self - Consolidated Concrete
 Shotcrete Concrete
 Pervious Concrete
 Stamped Concrete
 Limecrete
 Asphalt Concrete
 Roller Compacted Concrete
 Rapid Strength Concrete
 Glass Concrete
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35. Making of Concrete
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36. Making of Concrete
 Manufacturing of concrete involves in various stages as
explained below
● BATCHING
● MIXING
● TRANSPORTING
● PLACING
● COMPACTING
● CURING
● FINISHING
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37. Batching
 Batching
Batching is the process involves in measuring concrete mix ingredients by either mass
or volume and pouring ingredients into the mixer. To produce a uniform quality concrete
during manufacturing process, the ingredients must be measured accurately for each batch.
 There are two types of batching
1. Volume batching
2. Weight batching
 Volume batching
● This method is generally adopted for small jobs.
● Gauge boxes are used for measuring the fine and coarse aggregate.
● The volume of gauge box is equal to the volume of one bag of cement.
● The material should be filled loosely in the gauge boxes, no compaction is allowed.
 Weigh Batching
Batching by weight is more preferable in manufacturing of concrete than volume batching ,as
it is more accurate and leads to more uniform proportioning of concrete.
● Weigh batching does not have uncertainties associated with bulking.
● It’s equipment falls into 3 general categories :I. Manual, II. Semi automatic III. Fully
automatic
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38. Mixing
 During manufacturing process the mixing of concrete should ensure that the
mass becomes Homogeneous , uniform in colour and consistency.
 Methods of Mixing :
Hands(using hand shovels)
Stationary Mixers
Ready mix concrete
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39. Transporting and Placing
 Many ways can be used to transport the manufactured concrete to place in
required of concrete. Like Beam, column, foundations
 ● Mortar Pan : Concrete carried in small Quantities
 ● Wheelbarrows and Buggies : Short flat hauls on all types of onsite concrete
construction
 ● Belt Conveyors: Supplying concrete horizontally or higher/lower level.
 ● Cranes and Buckets: Used for Work above ground level, Buckets use with
Cranes, cableways, and helicopters.
 ● Pumps: supplying concrete from central discharge point to formwork.
 ● Transit Mixer: used for long
distance transporting the concrete
particularly in RMC plant
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40. Compaction of concrete
 ● Compaction of concrete is process that helps
in expelling the trapped air from the concrete
 ● During the process of mixing, transporting
and placing of concrete air is likely to get
trapped in the concrete.
 ● Studies say that 1% air in the concrete can
approximately reduces the strength of concrete
by 6%.
 ● If air is not expelled from concrete, it will
result in forming honeycombs and reduced
strength.
 Different Methods of Concrete Compaction
 1) Hand Compaction – Rodding, Ramming, Tamping
 2) Compaction by Vibration – Internal vibrator,
Formwork vibrator, Table Vibrator, Platform
vibrator, Surface vibrator. 9/30/2023 40

41. Curing
 Curing of freshly placed
concrete is very important for
optimum strength and
durability. The process of
keeping concrete damp for this
purpose is known as curing.
 The object is to prevent the
loss of moisture from concrete
due to evaporation or any
other reason.
 Curing must be done for at
least three weeks and in no
case for less than ten days.
There are many types of curing
methods which can be adopted
based of requirements.
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42. Finishing
 The reason Concrete is used
because of its high compressive
strength. However, the finish
of the ultimate product is not
that pleasant. In past couple
of decades efforts have been
made to develop surface
finishes to give a better
appearance to concrete surfaces
and are as follows.
 1. Formwork Finishes
 2. Surface Treatments
 3. Applied Finishes
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43. Application of concrete
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Concrete Dams Residential
Buildings
Commercial
Buildings
Roads or
Driveways
Marine
Construction
Culverts and
Sewers
Foundation
s
Concrete
Bridges

44. Admixtures
 Concrete admixtures are natural or manufactured
chemicals or additives added during concrete mixing to
change the properties / enhance specific properties of the
fresh or hardened concrete, such as workability, durability,
or early and final strength.
 The properties commonly modified are the heat of
hydration, accelerate or retard setting time, workability,
water reduction, dispersion and air-entrainment,
impermeability and durability factors.
Types of Admixtures
Chemical admixture:
Accelerators,
Retarders,
Water-reducing agents,
Super plasticizers,
Air entraining agents etc.
Mineral admixtures: fly ash, silica fume, rice husk. GGBS, etc
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45. Self-healing concrete
 Self-healing concrete is characterized as the capability of concrete to fix its cracks on its own
autogenously or autonomously. It not only seals the cracks but also partially or entirely recovers the
mechanical properties of the structural elements. This kind of concrete is also known as self-
repairing concrete
 Self-healing is an old and well-known phenomenon for concrete, given that it contains innate
autogenous healing characteristics. Cracks may heal over time due to continued hydration of clinker
minerals or carbonation of calcium hydroxide
 There are many solutions for improving autogenous healing by adding the admixtures, such as
mineral additions, crystalline admixtures, and superabsorbent polymers.[6] Further, concrete can be
modified to built-in autonomous self-healing techniques.
 The capsule-based self-healing, the vascular self-healing, and the microbiological self-healing are
the most common types of autonomous self-healing techniques
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46. light generating concrete /
 The light emitting concrete composition comprises light-emitting pigments. The light emitting pigments
include a titanium powder, a sulphide powder and resins, cement, sand, gravel and water. The method
of synthesizing a light emitting concrete structure comprises preparing slurry.
 Light-emitting cement is a green construction material designed to illuminate highways, roads, and bicycle
lanes without using electricity. Light-emitting cement absorbs solar energy during the day and radiates
light at night.
 This innovative cement was developed by Dr. Jose Carlos Rubio from the Michoacan University of Saint
Nicholas of Hidalgo in Mexico. The research focused on modifying
the microstructure of cement to absorb solar energy
and emit light in darkness.
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