use of waste material in concrete

7/29/2019 use of waste material in concrete

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WASTE & RECYCLED MATERIAL

IN CONCRETE TECHNOLOGY


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CONTENTS NEED OF RECYCLING OF WASTE MATERIALS

ROLE OF WASTE MATERIALS IN CEMENT CLINKER

PRODUCTION

PORTLAND CEMENT MANUFACTURE FROM WASTEMATERIALS

RECYCLING OF CONCRETE.

MINING & QUARRYING WASTES

APPLICATION OF MISCELLANEOUS WASTES ROLE OF WASTE MATERIAL AS AGGREGATES


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ABSTRACT

World wide consumption of concrete amounts to more than

1000 Kgs/person

The demand is expected to increase in future

Concrete comprises in quantity the largest of man madematerial


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INTRODUCTION

Concrete made with Portland cement ,water admixtures and

aggregates comprises in quantity the largest of all man made material

Historically whenever new compounds were produced ,or waste

materials accumulated in industries ,they were incorporated as one ofingredients of concrete. Typical examples are fly ash phosphogypsum,blastfurnace slag, saw mil waste, rice husk, cotton etc.The wide spread need forconserving resources & environment will be reflected major emphasis on theuse of wastes & by products.

Recycling of concrete materials also offers some promise. Attemptsare already being made to use municipal refuse & waste oil as partialsubstitutes for the fuel in the production of cement clinker


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NEED OF RECYCLING OF WASTE MATERIALS

Rise in population

Large scale demand for housing

Over stressing the reserves of traditional building

materials

Cement material presently not in a position to cope

the millions of the country

The enormous amount of waste materials Recycling becoming imperative & mandatory


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ROLE OF WASTE MATERIAL IN CEMENT

CLINKER PRODUCTION

Many waste materials contain basic ingredients that areneeded for the manufacturing of cement clinker

Fly ash can also be used as a source of raw material

Lime sludge can be used as a substitutes for lime stone

Red mud a waste material from the production of aluminaused as a raw material for cement clinker production

Phosphogypsum as a mineralizer for making clinker


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COMPRESSIVE STRENGTH OF MORTAR(MPA)

Cement 1 day 3 days 7 days 28 days

Phosphogypsum

Minerals

17.3 26.2 37.4 53.7

Normal Cement 8.2 22.0 37.4 50.0


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PORTLAND CEMENT MANUFACTURED

FROM WASTE MATERIALS

FLY ASH CEMENT

BLAST FURNACE SLAG CEMENT

RICE HUSK ASH CEMENT


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FLY ASH CEMENT

Fly ash is the ash component of Coal liberated duringcombustion .

Fly ash can be incorporated into Portland cement in one ofthe three ways.

Fly ash can be used as a admixture or as replacement ofPortland cement.

Fly ash addition to Portland cement results in increasedworkability.

In fly ash cement development of compressive strength isslow

At longer periods of curing Fly ash concrete develops higherstrengths than the normal concrete


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WHY CHARACTERISTICS?

Not a specially manufactured product governed by

strict rules

Variation in carbon, particle shape & size distribution,

presence of minerals etc..

Exhibits different characteristics with different

compounds.

No proper processing is available.

Change in the behavior of concrete.


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MACROSCOPIC VIEW OF FLY ASH


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FLY ASH

Finely divided residue resulting from combustion of

powdered coal.

Common ingredient in concrete.

First used in construction of Hungry Horse Dam in USA

In India, first used in Rihad Dam.

High volume fly ash is of current interest.

Quality of fly ash is governed by IS:3812-1981


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INFLUENCE OF FLY ASH ON STRENGTH

DEVELOPMENT IN CONCRETE


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PERMEABILITY OF FLY ASH CONCRETE


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Hungry Horse Dam, Montana,is a thick-arch structure

that was built between 1948 and 1953with concrete containing120,000 metric tons of fly ash.The use of coal fly ash in cementand concrete displaces Portlandcement.


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Fly ash used in the construction of buildings at Chennai


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Fly ash used in Delhi Metro


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Roman Coliseum: An classic example of Romanstructures which was build with fly ash concrete.


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WELCOME

ASH

CEMENT

3

DAYS

7 DAYS 28 DAYS 90 DAYS

70:30 31.9 45.4 58.7 63.9

50:50 26.1 39.0 57.6 60.7

30:70 24.0 35.4 42.7 50.1

0:100 22.4 32.5 42,4 47.4

COMPRESSIVE STRENGTH


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ADVANTAGES OF FLY ASH CONCRETE

Addition of fly ash to concrete minimize or eliminates

the expansion due to alkali aggregate reaction

WORKABILITY

TIME OF SETTING


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DURABILITY OF FLY ASH CONCRETE

Sufficiently cured fly ash concrete has dense structure &hence more resistance to deleterious substances.

This reduces the corrosion of reinforcement.

Class F fly ash reduces alkali-silica reactivity because of thedense structure & hence expansion is reduced whichincreases durability.

Because of the reduced permeability the chloride ingressis reduced.


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STRUCTURES USED FLY ASH ASH

Sl. No Structures State Cement replaced(%) Source of flyash

1. Gurgoantunnel Haryana 15 Delhi

2. Jawar sagarDam Rajasthan 20

Delhi3. Kakki Dam Kerala 20 Neyveli4. Navora

barrage U.P. 15 Harduaganj5. Rihad Dam

UP 15 Bokaro6.

Sone Barrage Bihar 15 Bokhara

7. UmiumProject Assam Not available Durgapur

8.Chandil dam Bihar 25 Talcher


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FLY ASH MISSION PROJECT SITES


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BLAST FURNACE SLAG CEMENT

Portland blast furnace slag cement can replace Portlandcement where high strength is not required.

It is produced by intergrinding Portland cement clinker &granulated blast furnace slag.

The workability of this cement is as good as Portland cementconcrete.

This is resistant to a number of aggressive agents includingsulphates of Al,Mg,NH4etc

The rate of hardening is slower than the normal Portlandcement concrete.

The 90 days strength is of Portland cement concrete.

More resistant to sea water &other chemical agents thanPortland cement.


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RICE HUSK


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RICE HUSK ASH CEMENT

In the rice milling operation one ton of rice paddy

produces 400 kg of husk. Burning of the husk results in 20% by

a weight of ash. Blending this ash with cement produces a

suitable blended cement


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ADVANTAGE

The rice husk ash cement on hydration

produces practically no Ca(OH)2 &hence is

superior to Portland.


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RECYCLING OF CONCRETE

Except structures which have to be preserved as moments a

great number of them have to be demolished sooner or later.

Concrete accounts of nearly 75% by weight of all construction

material.

Millions of tons of concrete debris are generated by natural

disaster.

Depletion of normal aggregate sources, stricter environmental

laws & waste disposal problems make recycling of concrete.


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WHAT IS CONCRETE RECYCLING?

Breaking , removing & crushing hardened concrete from

an acceptable source. Old concrete pavements often

are excellent sources of material for producing RCA

RECYCLING PROCESS


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RECYCLING PROCESS


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USES OF RECYCLED CONCRETE

Smaller pieces of concrete are used as gravel for new

construction projects.

Sub base gravels laid down as the lowest layer in a road.

Recycled concrete can also be used as the dry aggregate for

brand new concrete.

Larger pieces can be used for erosion control.


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DISADVANTAGES

Lead paint contamination.


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CONCRETE RECYCLING MACHINE


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MINING & QUARRYING WASTES

Large amount of wastes produced in mining & quarrying

operations.

Mineral mining wastes are waste rock or mill tailings.

Manufacturing of bricks ,light weight aggregates & autoclaved

concrete blocks.


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APPLICATION OF MISCELLANEOUS WASTES

Collier spoil

Waste glass

Red mud

Burnt clay

Saw dust


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COLLIERY SOIL

In coal operations about one half of the material is separated

& discarded as colliery soil.

This soil is used to fill in road embankments.

It can also be used to produce light weight concrete.


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WASTE GLASS

Millions of tons of waste glass are generated annually..

The strength of concrete less than with gravel aggregate.

This is used to make light weight aggregates.


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RED MUD

Red mud is a waste product resulting from the extraction of

alumina from bauxite ore.

It is sufficiently plastic to be moulded into balls.

Firing at about 1260 to 1310 c produces a strong dense

aggregate.


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BURNT CLAY

High permeability.

Concrete contains burnt clay has high fire resisting capacity.


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SAW DUST

Saw dust concrete is used only to a limited extent because of

its low strengths.

The addition of sand can improve strength.

Saw dust cement has a good insulation value .

Low thermal conductivity.

Concrete containing large amounts of saw dust is flammable.


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ROLE OF WASTE MATERIALS AS


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ROLE OF WASTE MATERIALS AS

AGGREGATES

Use of waste & byproducts as aggregates has greater

potential because 75% of concrete is composed of aggregates.

Various aggregates examined includes reclaimed concrete

mining & quarrying wastes, colliery soil, waste glass, red mud,

burnt clay & saw dust.


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CONCLUSION

In the coming future Recycling of Waste Materials

& by production for concrete technology will achieve new

heights, as attempts are already being made to use

municipal refuse & waste oil as partial substitutes for

production of cement clinker. We have to promote &

development in the area of utilization of waste materials.

Variability of the physical & chemical characteristics

& availability at locations far removed from populations

areas may inhibit the wide spread use of many types ofwastes. Future work will have to be directed to study of

the long term durability of concretes containing these

materials.


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use of waste material in concrete