Presented by:

Sneha

Himani

Naveen

Amit

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

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.

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.

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

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.

Manufacturing Of Cement

Mixing of raw material(wet or dry)

Burning

Grinding

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.

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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Dry process-available raw material is hard.

Mixing of raw materials undergo crushing, drying, reduction in size, mixing in correct proportion.

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

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

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

Characteristics

Strength- atleast 175kg/cm2

Fineness

Soundness

Presence of lumps

Colour

Resistant to moisture.

Setting time

Types of Cement Ordinary portland cement

Rapid hardening cement

High alumina cement

Blast furnace slag cement

Super sulphated cement

Low heat cement

Air entraining cement

Quick setting cement

Coloured cement

Whit cement

Acid resistance cemet

Hydrophobic cement

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.

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.

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

Coloured cement

◦ Can get colours by adding mineral pigments.

◦ Green(chromium oxide),blue(cobalt),red, brown, yellow(iron oxides)

◦ Used for decorations.

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.

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.

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

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.

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.

Tests

For fineness

◦ Sieve test

◦ Surface area test

For normal consistency –to determine the setting time

For soundness

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.

Cement as concrete

◦ For manufacturing solid and hollow concrete blocks.

◦ For laying subfloors and floors

◦ For RCC constructions(slab, beam, column, stairs, footings, etc)

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

Thank you