CE 6002 - CONCRETE TECHNOLOGY (UNIT I)

S.R.V ENGINEERING COLLEGE
DEPARTMENT OF CIVIL ENGINEERING
CE 6002 – CONCRETE TECHNOLOGY

1. DEFINITION OF CEMENT
2. MANUFACTURING PROCESS
3. TYPES OF CEMENT
4. GLOBAL SCENARIO
5. EVOLUTION OF INDIAN CEMENT FACTORY
6. Economic status
7. USES OF CEMENT
8. TESTS
9. Aggregates
10. Classification of aggregates
11. CHARACTERSTICS OF AGGREGATES
12. AGGREGATE TEST

•The word Cement has come from the Roman word
‘Opus Caementicium’
•Cement is a binder, a substance that sets and hardens independently,
and can bind other materials together.
•The most important use of cement is the production
of mortar and concrete—the bonding of natural or
artificial aggregates to form a strong building material that is durable in
the face of normal environmental effects.
•Joseph Aspdin, a British stonemason, invented Portland cement way
back in 1824. With this invention, Aspdin laid the foundation of today’s
cement industry.
What Is CEMENT?

MANUFACTURING PROCESS
Cement is made out of limestone, shale, clay mined out of quarry close to the
plant.
The raw material is crushed, and then heated at temperature in excess of 1000
degree Celsius in rotating kiln to become clinker.
Clinker is then mixed with gypsum and ground to a fine powder to produce final
grade of cement.
The technology is a continuous process
At present 93% of cement production in India is based on modern and
environment-friendly dry process technology and only 7% of the capacity is based
on old wet and semi-dry process technology.
The cost of Cement is 29% energy; 27% raw materials; 32% labour and 12%
depreciation

TYPES OF CEMENT
•Ordinary Portland Cement (OPC)
•Portland Pozzolana Cement (PPC)
•Portland Blast Furnace Slag Cement (PBFS)
•Oil Well Cement
•Rapid Hardening
• Sulphate Resisting Portland Cement
•White Cement etc.
The basic raw materials used in the cement manufacturing process are
limestone, sand, shale, clay, and iron ore.

GLOBAL SCENARIO
•Today, it is estimated that there are around 1500 integrated cement
production plants in the world.
•It is estimated that world cement consumption is to rise on an average
between 3.6% and 4.8% per year in the coming years.
•Most of the growth is coming from Central and Eastern Europe and Asia,
growth in mature markets also looks healthy.
•The share of the four largest firms account only for 23% of the overall
demand.
•LAFARGE and CEMEX have become very strong global cement players.

EVOLUTION OF INDIAN CEMENT FACTORY
•A Kolkata based company started manufacturing cement in 1889.
•In 1914, Indian Cement Company Ltd was established in Porbandar.
•In 1927, Concrete Association of India was set up to create public
awareness on the utility of cement.
•In 1956, price and distribution system of cement industry came under
government control.
•After the economic reform in 1980’s the government control on
cement industry was liberalized.
•A great increase in demand of cement, has resulted India to become
2nd largest cement producer in the world after China.

Growth Rate
Investments
Exports
FDI and GDP

•India is the world’s second largest producer of cement with total capacity of 224
million tonnes as on April 2010.
•Indian Cement Industry comprises of 140 large and more than 365 mini cement
plants.
•According to ACC cement report, Government’s continued thrust on
infrastructure will help the cement to maintain an annual growth of 9-10% in
2010.
•With addition in the cement production, it is expected that cement production in
India will reach 300 million tonnes in the coming years.

•Cement and gypsum products have received cumulative FDI of US$ 1708.69
million between April 2000 and March 2010, according to the Department of
Industrial Policy and Promotion.
•Madras Cements Ltd is planning to invest US$ 178.4 million to increase the
manufacturing capacity of its Ariyalur plant in Tamil Nadu to 4.5 MT from 2 MT
by April 2011.
•Shree Cement, plans to invest US$ 97.13 million this year to set up a 1.5 MT
clinker and grinding unit in Rajasthan. Moreover, in June 2010, Shree Cement
signed an MoU with the Karnataka government to invest US$ 423.6 million for
setting up a cement unit and a power plant.

•During 2007-08, the export of cement from India touched the 2.16
million tonnes mark. However during 2008-09, the cement export
from India stood at 1.46 million tonnes.
•In spite of seeing fall during 2008-09, the export segment of the
industry is expected to grow again on account of various
infrastructure projects that are being taken up all over the world. India
has an immense potential to tap markets of Middle East and South
East Asia
•The negative ACGR (Annual Compound Exponential Growth Rate)
of -5.52% in control period has seen ACGR of 35.35% in
decontrolled and opened up economy

•The industry occupies an important place in the national economy because
of its strong linkages to other sectors such as construction, transportation ,
coal and power.
•The cement industry is one of the major contributors to the exchequer by
way of indirect taxes.
•100% FDI is permitted in the cement industry.
•It contributes approximately 1.3% of GDP and the industry is employing
over 0.14 million people

•Production of Concrete
• Construction Purpose
o Building (Floors, Beams, Columns,
Roofing)
o Transport (Roads, Pathways, Crossings,
Bridge)
o Water (Pipes, Drains, Canals)
o Agriculture (Irrigation, Housing)

1. Field testing
2. Standard consistency test
3. Fineness test
4. Soundness test
5. Strength test

 Open the bag and take a good look at the cement, then it should
not contain any visible lumps.
 Colour of cement should be greenish grey.
 Should get cool feeling when thrusted.
 When we touch the cement, it should give a smooth &not a
gritty feeling.
 When we throw the cement on a bucket full of water before it
sinks the particles should flow.
 When we make a stiff paste of cement & cut it with sharp
edges & kept on a glass plate under water there wont be any
disturbance to the shape& should get strength after 24hours.

The standard consistency of a cement paste is defined as
that consistency which will permit a Vicat plunger
having 10 mm diameter and 50 mm length to penetrate
to a depth of 33-35 mm from the top of the mould.
USE:
Used to find out the percentage of water required to
produce a cement paste of standard consistency.
This is also called normal consistency (CPNC).

•For first trial, take about 500gms of cement & water of 24%by weight of cement.
•Fill it in Vicat’s mould with in 3-5min.
•After filling, shake the mould to expel air.
•A standard plunger, 10 mm diameter, 50 mm long is attached and brought down
to touch the surface of the paste and quickly released.
•Note the reading according to depth of penetration of the plunger.
Conduct trials continuously by taking different water cement ratios till the
plunger penetrates for a depth of 33-35mm from top.
This particular percentage is known as percentage of water required to produce
cement paste of standard consistency.
This is usually denoted as ‘P’.

 An arbitraty division has been made for the setting
time of cement.
 Initial setting time &
 Final setting time.

 The time elapsed between the moment that the water
is added to the cement, to the time that the paste starts
losing its plasticity.
 Normally a minimum of 30min has maintained for
mixing & handling operations.
 It should not be less than 30min.

 The time elapsed between the moment the water is
added to the cement, and the time when the paste has
completely lost its plasticity and has attained
sufficient firmness to resist certain definite pressure.
 It should not exceed 10hours.
 So that it is avoided from least vulnerable to damages
from external activities.

PROCEDURE:
•Take correctly 100grams of cement on a
standard IS sieve No.9
•Break down the air-set lumps & sieve it
&weigh it.
•This weight shall not exceed 10% for
ordinary cement.
•Sieve test is rarely used.

 It is very important that the cement after setting shall not undergo any
appreciable change of volume.
 This test is to ensure that the cement does not show any subsequent
expansions.
 The unsoundness in cement is due to the presence of excess of lime
combined with acidic oxide at the kiln.
 This is due to high proportion of magnesia & calcium sulphate.
 Therefore magnesia content in cement is limited to 6%.
 Gypsum 3-5.

 This is the most important of all properties of
hardened cement.
 Due to excessive shrinkage and cracking the
strength tests are not made on heat cement paste.
 Standard sand is used for finding the strength of
cement.

Aggregates are inert materials which are mixed with binding material
such as cement or lime for manufacturing of mortar or concrete.
Aggregates are used as filler in mortar and concrete and also to reduce
their cost.
(1) Fine aggregates
(2) Coarse aggregates

Aggregates whose 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.
It consists of small angular or rounded grains of
silica depending upon the source from which it is
obtained. It is classified as:
(i) Pit or quarry sand
(ii) River Sand
(iii) Sea Sand

(i) Pit or quarry sand
It is found 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.
(ii) 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.
(iii) 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.

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).

Aggregates whose particles do not pass through 4.75 mm IS are termed
as coarse aggregates. Most commonly used coarse aggregates are
crushed stone, gravel; broken pieces of burnt bricks,etc.
It is an excellent coarse aggregate and is obtained by crushing granite,
sand stone or grained lime stone and all types of stones. Crushed stones
are used for the construction of roads and railway tracks, etc.
It is an other very good coarse aggregate. It is obtained from river beds,
quarries and sea shores. The gravel obtained from sea shores should be
well washed with fresh water before use in order to remove the impurities
which may be clay, salts ,silt,etc. It is commonly used in the preparation
of concrete.

It is also a good artificial source of coarse aggregates. It is obtained by
breaking well burnt bricks. It is generally used in lime concrete at places where
aggregates from natural sources are either not available or are expensive. It can
be used at places where low strength is required. It should be watered well
before using it in the preparation of concrete. It is commonly used for mass
concrete in foundations and under floors.
(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.

Aggregate containing the constituents which generally react with alkalies in
cement cause excessive expansion, cracking of concrete mix, should never be
used. Suitability of aggregates should be judged either by studying its service
history or by laboratory tests.
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.

The aggregate crushing value gives a relative measure of resistance of
an aggregate to crushing under a gradually applied compressive load.
The aggregate crushing strength value is useful factor to know the
behaviour of aggregates when subjected to wear.
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.
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.

CE 6002 - CONCRETE TECHNOLOGY (UNIT I)

CE 6002 - CONCRETE TECHNOLOGY (UNIT I)

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