The document discusses the process of cement manufacturing. It begins with the raw materials used, which include limestone, clay, iron oxide, and aluminum. These materials are quarries, crushed, and transported to a plant for storage. They are then ground together and preheated before being burned in a kiln at 1500°C to produce clinker. The clinker is cooled, ground with gypsum, and stored in silos before being packaged and distributed. The document outlines the characteristics, types, grades, setting process, optimal storage conditions, and common uses of cement in construction.
2. Table of Contents
Introduction
History
Raw materials of cement
Manufacturing of cement
Characteristics of cement
Types of cement and their Properties
Grades of cement
Function of cement
◦ Setting
◦ Ratio of mixture
Storage of cement
Tests
Uses of cement
Conclusion
3. Introduction
Cement is a building
material for binding bricks,
stones or aggregates.
Used for making mortar or
concrete.
Cements natural and
artificial.
Natural cement-burning
and crushing of stones and
lime.
Artificial cement-burning
at high temperature and
gypsum is added.
4. History
1756-John Smeaton (England) created hydraulic
lime from lime stone.
1796- John Parker(England) created an improved
version. Birth of natural cement industry.
1824-portland cement was invented by Joseph
Aspedin. It resembled the colour of sand stone
found in Portland, U.K .
1904-First cement factory in Tamil Nadu, India.
5. Raw material
ingredient range approximate
lime 60-65% 63
Silica 17-25% 21
Alumina 4-8% 6
Iron oxide 1-6% 3
Magnesia 1-3% 1.5
Calcium sulphate 3-5% 4
Sulphur 1-3% 1
Alkalies 0.2-1% 0.5
6. Lime- excess will decrease the strength. Deficiency
will make it set quickly.
Silica- higher silica increases the strength but setting
time is prolonged.
Alumina- results in quick setting. Excess alumina
weakens cement.
Iron oxide- for colour hardness and strength.
Magnesia- hardness and colour.
8. 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.
9. Grinding- cooled
clinkers are ground
and gypsum is
added.
As cement comes
out of grinding mill
it is collected in
hopper for storage
in silos.
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10. Dry process-available raw material is hard.
Mixing of raw materials undergo crushing, drying,
reduction in size, mixing in correct proportion.
11.
12. THE CEMENT MANUFACTURING PROCESS
1. BLASTING : The raw materials that are used to manufacture cement (mainly limestone and clay) are blasted
from the quarry.
Quarry face
1. BLASTING 2. TRANSPORT
3. CRUSHING AND TRANSPORTATION : The raw materials, after crushing, are
transported to the plant by conveyor. The plant stores the materials before they are
homogenized.
quarry
3. CRUSHING & TRANSPORTATION
2. TRANSPORT : The raw materials are loaded into a dumper.
crushing
conveyor
Next
dumper
storage at
the plant
loader
13. THE CEMENT MANUFACTURING PROCESS
1. RAW GRINDING : The raw materials are very finely ground in order to produce the raw mix.
1. RAW GRINDING
Raw grinding and burning
2. BURNING
2. BURNING : The raw mix is preheated before it goes into the kiln, which is heated by a flame that can
be as hot as 2000 °C. The raw mix burns at 1500 °C producing clinker which, when it leaves the kiln, is
rapidly cooled with air fans. So, the raw mix is burnt to produce clinker : the basic material needed to
make cement.
conveyor
Next
Raw mix
kiln
cooling
Back
preheating
clinker
storage at
the plant
Raw mill
14. THE CEMENT MANUFACTURING PROCESS
1.GRINDING : The clinker and the gypsum are very finely ground giving a “pure cement”. Other secondary
additives and cementitious materials can also be added to make a blended cement.
1. GRINDING
Grinding, storage, packing, dispatch
2. STORAGE, PACKING, DISPATCH
2. STORAGE, PACKING, DISPATCH :The cement is stored in silos before being dispatched either in
bulk or in bags to its final destination.
Back
clinker
storage
Gypsum and the secondary additives are added
to the clinker.
silos
Home page
dispatch
bags
Finish grinding
17. Ordinary portland cement
◦ Most commonly used cement
◦ Moderate strength
◦ Less heat of hydration but does not cause any
defect.
◦ Mainly used in pavements and buildings.
◦ Normal setting time.(initial setting 30mins, final
setting 8hrs, hardening in 3days)
Rapid hardening cement
◦ hardens in 1 day.
◦ Stronger than OPC
◦ light weight, extra fine
◦ Mainly used in highways, under water structures and
in cold weather areas.
18. High alumina cement
◦ Long setting time(initial setting time 3-
5hrs)
◦ Very high compressive strength
◦ High resistance to sulphate
◦ Used in sea water construction.
◦ High heat of hydration
◦ Highly resistant to corrosion and temp.
◦ Very expensive, unsuitable for massive
construction.
◦ Extra care required.
19. Blast furnace slag cement
◦ Low heat of hydration
◦ Not suitable for dry acid zones
◦ Less strength than other cement, need longer curing
period.
◦ cheap
Quick setting cement
◦ Higher aluminium sulphate content.
◦ Sets in 5mins and final setting 30mins.
◦ Extra care required, hardens very quickly
◦ Used in running water
20. Coloured cement
◦ Can get colours by adding
mineral pigments.
◦ Green(chromium
oxide),blue(cobalt),red,
brown, yellow(iron oxides)
◦ Used for decorations.
21. White cement
◦ Raw material-pure white
chalk(lime stone)
◦ Free from iron oxide and
manganese oxide.
◦ Dries quickly.
◦ Used for plastering or
ornamental flooring or
marking.
22. Grades of Cement
Grades signifies the strength of cement after 28
days.
Grade 33- attains 33N/mm2 in 28days, when the
mortar of cement and sand is 1:3. initial setting
time 30mins and final setting time maximum
10hrs.
Grade 43- attains 43N/mm2 in 28 days
Grade 53- attains 53N/mm2 in 28 days.
23. Setting of Cement
Setting-when water is mixed
with cement, the action of
changing from flux to solid
state.
During the next stage of
hydration, paste gains
strength and starts hardening.
Initial setting time period-is
the time required when the
cement paste looses its
plasticity. For OPC- 30mins
Final setting time period- is
the time required to achieve
hardness. For OPC – 10hrs
24. Abram’s Law
water to cement ratio
Strength of fully
compacted concrete is
inversely proportional to
water cement ratio.
In practice, around 40%
water is used.
Practically, if we use less
water the mixture becomes
very stiff and difficult to
handle.
25. Storage Guidelines
Away from moisture.
Storage period should be short.
If long, should be stored in steel
drums
Avoid jute bags
More frequent delivery of
smaller lots
Damp proof sheds
Bags should be stacked in piles.
Not more than 10bags in a pile.
Cover with taurpaulin
Ensure FIFO.
26. Tests
For fineness
◦ Sieve test
◦ Surface area test
For normal consistency –
to determine the setting
time
For soundness
27. Application of Cement
Cement as mortar
◦ For laying or binding masonry
units(bricks ,stones,etc)
◦ For pointing the masonry joints
◦ For plastering the surface to
protect from weather.
◦ For decorative finish
◦ For filler material in ferro
cement construction.
◦ For damp proof course below
the ground level.
◦ Water proofing, crack repairs
and structures.
28. Cement as concrete
◦ For manufacturing solid
and hollow concrete
blocks.
◦ For laying subfloors and
floors
◦ For RCC
constructions(slab,
beam, column, stairs,
footings, etc)
29. Recap
Introduction
History
Raw materials of cement
Manufacturing of cement
Characteristics of cement
Types of cement and their Properties
Grades of cement
Function of cement
◦ Setting
◦ Ratio of mixture
Storage of cement
Tests
Uses of cement
Conclusion