cement, types of cement types of cement .pptx

INTRODUCTION
• Cement is a fine, soft, powdery-type substance
• Cement is a binder, a substance used in construction that hardens when
mixed with water. It is the key ingredient in concrete and mortar making
it one of the most widely used construction materials worldwide.
• When cement is mixed with water, it can bind sand and aggregates into a
hard, solid mass called concrete.

Importance of Cement
• Provides strength and durability to structures
• Used in various forms of construction (buildings, bridges,
roads, dams, etc.)
• Enhances workability and stability in different
environmental conditions

• In 1824, Joseph Aspdin, a British stone mason, heated a mixture of finely
ground limestone and clay in his kitchen stove and ground the mixture
into a powder to create a hydraulic cement—one that hardens with the
addition of water.
• A variety of sandstone is found in abundance in Portland in England
hence it is called as “ ORDINARY PORTLAND CEMENT “
• In India, the first cement factory was installed at Tamil Nadu (1904) by
South India Industry Limited
HISTORY OF CEMENT

Four essential elements are needed to make cement. They are Calcium,
Silicon, Aluminum and Iron.
• Calcium (which is the main ingredient) can be obtained from limestone,
whereas silicon can be obtained from sand.
• Aluminum and iron can be extracted from bauxite and iron ore and only
small amounts are needed.
CHEMICAL COMPOSITION OF CEMENT

• These oxides interact with one another in the kiln at high temperature to
form more complex compounds.
• The relative proportions of these oxide compositions are responsible for
influencing the various properties of cement, in addition to rate of cooling
and fineness of grinding.

CHEMICAL COMPOSITION OF CEMENT

FUNCTIONS OF INGREDIENTS OF CEMENT
Lime (CaO)
Lime forms nearly two-third (2/3) of the cement. Therefore sufficient quantity of the lime
must be in the raw materials for the manufacturing of cement.
Its proportion has an important effect on the cement. Sufficient quantity of lime forms
dicalcium silicate and tri-calcium silicate in the manufacturing of cement.
• Excess quantity of lime makes the cement unsound
• Lime in excess, causes the cement to expand and disintegrate
• If it is less, it decreases the strength and allows the cement to set quickly

Silica (SiO2)
The quantity of silica should be enough to form di-calcium silicate and tri-
calcium silicate in the manufacturing of cement.
• An important ingredient which gives strength to cement
• If it is in excess silica allows the cement to set slowly (setting time is
prolonged)

Alumina(Al2O3)
• This imparts quick setting time to the cement.
• If it is in excess quantity, it weakens the cement.
• It also lowers the temperature of clinkers. (Alumina reduces the
melting point of raw materials in cement kilns, making production
more energy-efficient.
Iron Oxide (Fe2O3)
• It helps the fusion of the raw materials during burning stage.
• It gives colour, strength and hardness to cement.

Magnesium Oxide (MgO)
• If present in small quantities, MgO imparts hardness and color to cement.
• If becomes excess quantity, weakens the cement, make cement unsound.
Sulphur (S)
• A very small quantity is required in the manufacturing of cement.
• Proper sulfate levels can enhance early strength development
• If it is in excess, SO3 makes the cement unsound.

Alkalies
• A small quantity are required.
• Alkalies and other impurities present in raw materials are carried by the flue gases
during heating.
• If it is in excess quantity, efflorescence is caused.
• Alkalis in cement affect setting time, strength, and durability. While small amounts
can be beneficial, excess alkalis can cause cracking and durability issue making
proper control essential.

TYPES OF CEMENT
1. Ordinary Portland Cement
2. Rapid Hardening Cement (or) High Early Strength cement
3. Extra Rapid Hardening Cement
4. Sulphate Resisting Cement
5. Quick Setting Cement
6. Low Heat Cement
7. Portland Pozzolana Cement
8. Portland Slag Cement
9. High Alumina Cement
10. Air Entraining Cement
11. Super sulphated Cement
12. Masonry Cement
13. Expansive Cement
14. White Cement

ORDINARY PORTLAND CEMENT
It is called Portland cement because on hardening (setting)
its colour resembles to rocks (Portland stone) near Portland
in England. It was first of all introduced in 1824 by Joseph Asp
din, England.
• Most important type
• Classified into 3 grades, namely 33 grade, 43 grade and 53
grade.

Chemical Composition of O. P. Cement
O.P.C has the following approximate chemical
composition:
The major constituents are:
1. Lime (CaO) 60- 63%
2. Silica (SiO2) 17- 25%
3. Alumina (Al2O3) 03- 08%

The raw materials required for manufacturing of cement are calcareous
materials, such as lime stones or chalk, and argillaceous (silica and
Alumina) materials such as shale or clay and Gypsum
Lime stones Shale
MANUFACTURING OF PORTLAND CEMENT

Calcium Sulphate (or) Gypsum (CaSO4)
At the final stage of manufacturing, gypsum is
added to increase the setting of cement.

Cement is usually manufactured by two processes:
1. Wet process
2. Dry process
There are five stages in manufacturing of cement by wet process:
1. Crushing and grinding of raw material
2. Mixing the material in proportion
3. Heating the prepared mixture in rotary kiln
4. Grinding the heated product known as clinker
5. Mixing and grinding of cement clinker with gypsum
Mixing of raw material
clinker

MANUFACTURING OF PORTLAND CEMENT
• The soft raw materials are first crushed into suitable size (25 mm in crusher)
and dry air is passed through the material.
• This is done usually in cylindrical ball or tube mills containing the charge of
steel balls.
Note :- All operations done separately for each raw material
• Now they stored in hopper .
• Mixed in correct proportions and made ready for rotary kiln
• The finely powdered of raw material is called as Raw Mix and stored in
storage tank.
Mixing of raw material (Dry Process)

WET PROCESS
• when raw materials are soft.
• Raw materials are mixed and crushed, stored in silos.
• Crushed material from different silos are drawn in appropriate
proportion in a channel called wet grinding mill.
• Mixed with water called slurry. Stored in slurry silo.
• Slurry fed in rotary kiln passing through 3 zones-dry zone,
burning zone and cooling zone.

BURNING
Rotary Kiln for Burning

Raw mix Feed into a preheating tower where it is heated (DIA. 2.5-3 m, length- 90-
120m).
•kiln rotates at about 1-3 revolution per minute.
• The slurry gradually descends, and with rise in temp. CO2 of slurry is evaporated.
• Small lumps (nodules) formed at this stage gradually rolls down to burning zone
(Temp. 1400- 1500 deg. C).
• The product formed at this zone is calcined product and nodules converted into
small hard greenish blue balls known as clinkers.
BURNING

• For dry process, coal is pulverized through vertical coal mill and stored in silos.
• Pumped through burner with required quantity of air.
• Preheated raw material rolls down through kiln and heated at such extent so that
CO2 is driven off with combustion gases.
• Material is heated at temp. 1400-1500 deg C to fuse together and fused product is
known as clinkers.
At the burning zone the temp of clinker is very high, at the outlet temp. is about 1000
deg C.

It is a common variety of cement
• It is suitable for the construction of all civil engineering works except under
water constructions
Uses of Ordinary Portland Cement
• Used in all important structures where great strength is required such as
heavy
buildings and bridges light houses, docks, reservoirs, etc,.
• Foundations in wet places, and structures subjected to the action of water
such as • Retaining walls
USES OF OPC (ORDINARY PORTLAND CEMENT)

• Cement mortar for plastering, pointing etc
• Plain concrete
For making
• Reinforced cement concrete for laying floors ,roofs, lintels, beams, etc,.
• Reinforced brick work
• In drainage and water supply works like water storage tanks, septic, tanks, etc,.
• For protecting the external faces of buildings or engineering structures from weathering
action
• For thin masonry works, where strength is required • Making joints for drains, pipes etc,.
• Manufacturing of precast pipes, piles, garden benches, fencing posts, flower pots, etc,.
• Preparation of foundations, footpaths, etc,.

RAPID HARDENING CEMENT
Also known as early gain in strength of cement. This cement contains more %age of
C3S and less %age of C2S, high proportion of C3S will impart quicker hydration
• The high strength at early stage is due to finer grinding, as fineness of cement will
expose greater surface area for the action of water.
•The strength obtained by this cement in 03 days is same as obtained by O.P.C in 7
days.
• Initial and final setting times are same as OPC i.e. 30mins and 10 hrs. And soundness
test by Le-Chatielier is 10mm
• Greater lime content than OPC

EXTRA RAPID HARDENING CEMENT
• It is obtained by intergrinding Cacl2 with rapid hardening cement.
• Addition of Cacl2 should not exceed 2% by weight of the rapid
hardening cement.
• Concrete made by using this cement should be transported, placed,
compacted & finished within about 20 minutes.
• Strength is higher than 25% than that of rapid hardening cement at 1 or
2 days.

SULPHATE RESISTING CEMENT
•It is modified form of O.P.C and is specially manufactured to
resist the sulphates.
•This cement contains a low %age of C3A and high %age of
C3S
•This cement requires longer period of curing.
•It develops strength slowly, but ultimately it is as strong as
O.P.C.

QUICK SETTING CEMENT
• This cement is manufactured by adding small %age of aluminum sulphate
(Al2SO4) which accelerates the setting action.
• Gypsum content is reduced.
• Sets faster than OPC.
• Initial setting time is 5 minutes. Final setting time is 30 minutes.

LOW HEAT CEMENT
• Low percentage of tri-calcium aluminates (C3A) and silicate (C3S) and
high %age of di-calcium silicate (C2S) to keep heat generation low.
• Very slow rate of developing strength as rate of C3S Content is low.
•Heat evolved @ 7 days-66 cal/g and 28 days-75 cal/g
•initial set time-1 hr, final set time-10 hrs
•Better resistance to chemical attack than OPC.

Portland Pozzolana Cement
• OPC clinker and Pozzolana (Calcined Clay, Surkhi and Fly
ash) ground together.
Produces less heat of hydration and offers great resistance to
attacks of Sulphates.
• Used in marine works and mass concreting.
• Ultimate strength is more than OPC.
• Low shrinkage on drying
• Water tightness.

Portland Slag Cement
• Produced by mixing Portland cement clinker, gypsum and
granulated blast furnace slag which shall not exceed 65%
• blackish grey in color.
• Lesser heat of hydration.
• Suitable for marine works, mass concreting.
• Offers good resistance to the attack of sulphate.

HIGH ALUMINA CEMENT
Different from OPC
• Characterised by its dark colour, high heat of hydration and resistance
to chemical attack.
• Initial setting time of 4 hrs and final setting time of 5hrs.
• Raw materials used are limestone and bauxite

AIR ENTRAINING CEMENT
• OPC with small quantity of air entraining materials (oils, fats, fatty
acids) ground together.
• Air is entrained in the form of tiny air bubbles which enhances
workability and reduces segregation and bleeding.
•It increases sulphate water resistance of concrete.

Supersulphated Cement
• Ground blast furnace slag + OPC +CASO4.
Heat of hydration which is considerably lower.
• It is also resistant to Sulphate attack.
• Used in a) Marine Structures, b) Mass concrete works

Masonry Cement
• Unlike ordinary cement, it is more plastic.
• Made by mixing hydrated lime, crushed stone, granulated
slag or highly colloidal clays are mixed with it.
• Addition of above mentioned materials reduces the
strength of cement.

Expansive Cement
• The main difference in this cement is the increase in volume that
occurs when it settles.
• Used to neutralize shrinkage of concrete made from ordinary
cement so as to eliminate cracks. A small percentage of this
cement with concrete will
not let it crack. It is specially desirable for hydraulic structures.
• In repair work, it is essential that the new concrete should be
tight fitting in the old concrete. This can be done by using this

Colored Cement
• Suitable pigments used to impart desired color.
• Pigments used should be durable under light, sun
or weather.

WHITE CEMENT
• OPC with pure white color produced with white
chalk or clay free from iron oxide.
• As iron oxide gives the grey colour to cement, it is
therefore necessary for white cement to keep the
content of iron oxide as low as possible.
• Instead of coal, oil fuel is used for burning.

TESTS FOR CEMENT
Field Tests Lab Tests
Colour
Presence of lumps
Strength
Fineness
Compressive strength
Tensile strength
Consistency
Setting Times
Soundness

Thrust your hand into the cement
bag. It must be giving you a cool
feeling.
 It feels smooth when rubbed it in
between fingers.
Open the bag and take a good look at the
cement. There should not be any visible
lumps.
 The colour of the cement should
normally in greenish grey.
FIELD TESTS OF CEMENT

Take another handful sample of cement and throw it in the bucket full
of water.
Particles of cement should float a while before sinking down.

• The fineness test of cement is conducted to determine the particle size
of cement and ensure it meets the required standards.
• Finer cement has a larger surface area, leading to faster chemical
reactions with water (hydration). This results in early strength gain,
which is crucial for rapid construction
• Finer cement improves the mixing and workability of concrete.
•Fineness testing ensures that cement is finely ground for better
performance, workability, strength, and durability. However, excessive
fineness can lead to shrinkage and cracks.
FINENESS TEST

Sieve Test for Fineness
Fineness of cement is measured by sieving it on standard sieve. The
proportion of cement of which the grain sizes are larger than the
specified mesh size is thus determined.
Standard size of the sieve for the test is 90μm.

PROCEDURE:
•Take correctly 100 grams of cement on a standard IS sieve of size 90
micron.
•Break down the air-set lumps & sieve it & weigh it.
•This weight of residue shall not exceed 10% .

Soundness Test
In the soundness test a specimen of hardened cement paste is boiled for a fixed
time so that any tendency to expand is speeded up and can be detected.
Soundness means the ability to resist volume expansion.
Le Chatelier's apparatus

 It consists of a small split cylinder of spring brass.
 It is 30mm diameter & 30mm high.

 This is immersed in water at a temperature 27deg C-32 deg C for 24 hours.
 Measure the distance between indicators.
 Heat the water & bring to boiling point of about 25-30min.
 Remove the mould from the water after 3 hours.
 Measure the distance between the indicators.
 This must not exceed 10mm for ordinary, rapid hardening, low heat Portland
cements.
 If this expansion is more than 10mm the cement is said to be unsound.

Standard Consistency Test
The standard consistency test of cement
determines the amount of water required
to form a cement paste of standard
consistency. This is the water content at
which the paste allows a Vicat plunger to
penetrate 5-7 mm from the bottom of the
mold.

Importance of Standard Consistency
• Ensures the correct water-cement ratio for proper
hydration.
• Helps in determining water content for other tests like
setting time and soundness tests.
• Prevents excess water, which can cause low strength and
shrinkage cracks.

Procedure
• Weigh 400 g of cement and place it in a mixing tray.Add water
(about 25% of cement weight) and mix thoroughly for 3-5
minutes.
• Fill the Vicat mold with the cement paste and level the surface.
Lower the Vicat plunger onto the paste and release it freely.
• Measure penetration depth of the plunger.
• Adjust water content and repeat the test until the penetration
is 5-7 mm from the bottom

Setting Time Test
• 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 30 min has maintained for mixing & handling
operations.
• It should not be less than 30min.
INITIAL SETTING TIME

• Mix 400 g of cement with water (P% of standard
consistency).
• Fill the Vicat mold with the paste and level it.Insert the
1 mm Vicat needle every 2 minutes.
• Record the time when penetration is less than 5 mm
from the bottom.

FINAL SETTING TIME
• 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.
• Apparatus Required: Vicat’s Apparatus (with 5 mm needle with an annular collar),
Vicat mold, Weighing balance, Stopwatch, Mixing tray & trowel

STRENGTH TEST
• This is the most important of all properties of hardened cement.
• The strength test of cement determines its load-bearing capacity and durability.
It ensures quality compliance and prevents structural failures.
This test is crucial for safe and long-lasting construction.
Standard sand is used for finding the strength of cement.

• Take 1:3 ratio of cement and sand to form mortar.
• Mix them for 1min, then add water of quantity(P/4)+3.0%.
where P is the percentage of water required to produce the standard consistency.
• Mix three ingredients thoroughly until the mixture is of uniform colour.
• The time of mixing should not be<3min and >4min.
• Then the mortar is filled into a cube mould of 70.6 mm and 76mm and area of 50
cm2.
• Compact the mortar.
• Keep the compacted cube in the mould at a temperature of 27°C ± 2°C least 90 for
24 hours.

• After 24hours the cubes are removed & immersed in clean fresh water until
taken for testing.
• The cubes are tested for compressive stress for 3, 7 and 28 days.
• The comp. stress of OPC should not be less than 11.5 N/mm2 at end of 3 days
, 17.50 N/mm2 a end of 7 days.

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