STAR LION COLLEGE OF ENGINEERING AND TECHNOLOGY,

CE6506 CONSTRUCTION TECHNIQUES,

EQUIPMENT AND PRACTICE

M.ANBARASAN M.E (Structures)

Asst. Professor

STAR LION COLLEGE OF ENGINEERING AND TECHNOLOGY,

MANANGORAI - THANJAVUR.

Lecture notes

2

ANBARASAN M.E (STRUCTURES) ASST.PROFESSOR -SLCET. www.Vidyarthiplus.com

OBJECTIVE

The main objective of this course is to make the student aware of the various construction techniques, practices and the equipment needed for different types of construction activities. At the end of this course the student shall have a reasonable knowledge about the various construction procedures for sub to super structure and also the equipment needed for construction of various types of structures from foundation to super

TEXT BOOKS

S.no Book title Author Publication

1

Construction Planning, Equipment and Methods

Peurifoy, R.L., Ledbetter, W.B. and Schexnayder, C.,

McGraw Hill, Singapore, 1995

2 Building Construction, Planning Techniques and Method of Construction

Arora S.P. and Bindra S.P.,

Dhanpat Rai and Sons, 1997.

3 . Building construction,. Varghese , P.C Prentice Hall of India Pvt. Ltd, New Delhi, 2007

4 Concrete Technology, Theory and Practice, .

Sheety, M.S, S. Chand and Company Ltd, New Delhi, 2005

REFERENCE BOOKS

5 Construction and Foundation Engineering

Jha J and Sinha S.K., Khanna Publishers, 1993

6 Construction Equipment and Management Sharma S.C.

Khanna Publishers New Delhi, 1988.

7 Construction Equipment and Job Planning

Deodhar, S.V. Khanna Publishers, New Delhi 1988.

8 Construction Equipment and its Planning and Application

Dr. Mahesh Varma Metropolitan Book Company, New Delhi-, 1983.

9 Concrete Technology Gambhir, M.L

Tata McGraw – Hill Publishing Company Ltd, New Delhi, 2004

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UNIT – I

Class notes

CEMENT : Definition, Grades, Types, Manufacture, Testing

CONCRETE : Definition

Manufacture - batching, mixing , transporting, placing, compaction, curing, finishing

Testing – fresh & hardened (non-destructive)

Quality of concrete

Application

Concrete Chemicals

MIX DESIGN : BIS & ACI method

CEMENT

Definition

Cement is a substance acts as a binding agent for materials.

It is obtained by burning the mixture of calcareous material such as limestone and

argillaceous materials such as clay at a high temperature.

There are two main constituents in Portland cement:

Argillaceous materials - clay

Calcareous materials – calcium carbonate.

COMPOSITION OF ORDINARY CEMENT

INGRIDENT PERCENT

Lime 62

Silica 22

Alumina 5

Calcium sulphate 4

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Iron oxide 3

Magnesia 2

Sulphur 1

Alkalies 1

SETTING ACTION OF CEMENT

When water is added to cement, ingredients of cement react chemically with

water and forms chemical compounds which impart strength to the cement.

This is known as setting action of cement.

Chemical compounds produced are ….

Tricalcium aluminate

Tricalcium silicate

Dicalcium silicate

Tetra –calcium alumino ferrite.

Usually cement attains about 70% of its final strength in 28 days and about 90% of its final

strength in one year or so.

MANUFACTURE OF PORTLAND CEMENT

There are three operations involved in manufacture of Portland cement:

Mixing of raw materials

Burning

Grinding

Mixing of raw materials

There are two methods in mixing of raw materials of cement:

Dry process

Wet process.

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BURNING

Burning is carried out in rotary kiln.

Diameter of kiln is 250-300 cm; length is 90-120 m and inclined about 1 in 20 to 30.

It is supported on rollers.

Refractory lining is provided on the inner surface.

Slurry is injected at upper end and it descends to burning zone carbon-dioxide gets

evaporated and forms nodules.

Temperature is about 1500-1700 c.

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In burning zone the lime and clay in the slurry get chemically fused to form hard balls of

Portland cement known as clinkers (Size 5 to 10mm).

GRINDING

Grinding is done in ball mills and tube mills.

Gypsum is added about 3 to 4 percent during grinding.

Gypsum controls initial setting time of cement.

Finely ground cement is stored in silos.

It is weighed and packed in bags.

Each bag contains 50Kg of cement.

The bags are stored in dry places.

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PROPERTIES OF CEMENT

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It is an excellent binding material.

Gives strength to masonry.

Possesses a good plasticity.

Offers a good resistance to moisture.

Easily workable.

It hardens quickly after addition of water.

The colour of cement should be uniform.

Cement should be free from lumps.

Cement should feel smooth when touched or rubbed in between fingers.

If a small quantity of cement is thrown into a bucket of water, it should sink and should not

float on the surface.

Average compressive strength of cement mortar should not be less than 11.5 N/mm2 at

3days and 17.5 N/mm2 at 7days.

Average tensile strength of cement mortar should not be less than 2 N/mm2 at 3days and

2.5 N/mm2 at 7days.

The initial setting time should not be less than 30 mins and final setting time should not be

more than 600 mins.

The loss of ignition should be within 4%

The specific surface of cement should not be less than 2250 cm2 /gm.

If the cement is sieved on 90 micron sieve for 15 mins, the residue by weight should be

within 10%.

USES OF CEMENT

It is used for constructing engineering structures such as dams, bridges, storage

reservoirs.

Used for making joints for pipes, drains.

Used for preparation of foundations, footpath.

Used for manufacture of precast pipes, fencing posts.

Used for masonry work, plastering, pointing.

Used for laying floors, roofs and constructing lintels.

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Used for protecting the structures from weather.

TYPES OF CEMENT

TESTING OF CEMENT:

Testing of cement can be brought under two categories:

• Field testing

• Laboratory testing

Field testing – sufficient to subject the cement to field tests when it is

used for minor works.

Open the bag and take a look at the cement. There should not be any

visible lumps. The colour of the cement should normally be greenish

grey.

Thrust your hand into the cement bag. It must give you a cool feeling.

Take a pinch of cement and feel between the fingers. It should give a

smooth and not a gritty feeling.

Quick setting cement

Low heat cement

High alumina cement

Expanding cement

Rapid hardening cement

Acid resistant cement

Sulphate resisting cement

White cement

Coloured cement

Blast furnace cement

Pozzolana cement

Air – entraining cement

Masonry cement

Oil-well cement

Redi-set cement

High strength cement

Hydrophobic cement

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Take a handful of cement and throw it on a bucket full of water, the

particles should float for some time before they sink.

Take about 100 grams of cement and a small quantity of water and

make a stiff paste (cake should not disturb when take into the water)

Laboratory testing - for using cement in major works, the laboratory test

are carried out.

The following are carried out in laboratory:

Fineness test (sieve analysis)

Setting time test(standard consistency)

Strength test(compressive strength)

Soundness test(le chatelier)

Heat of hydration test(vacuum flask method)

Chemical composition test

Strength test:

Compressive strength is most important.

The standard sand is used for finding the strength of cement.

FINENESS TEST

Fineness of cement is important bearing on the rate of hydration and on

rate of gain of strength.

Finer cement offers a greater surface area and hence faster and greater

the development of strength.

Fineness of cement is tested in two ways:

By sieving.

By determination of specific surface by air- permeability.

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SETTING TIME TEST:

An arbitrary division has been made for the setting time of cement as

initial setting and final setting time.

Initial setting time- is the time elapsed between the moments that the

water is added to the cement to the time that the paste starts losing its

plasticity.

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 sufficient firmness to resist pressure.

The test is carried out in vicat apparatus.

CONCRETE

Definition

Concrete may be defined as a building material obtained by mixing

cement, fine, coarse aggregates and water in suitable proportions.

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It is plastic mixture after curing it becomes hard mass.

The coarse aggregates are broken stone, broken bricks or gravel, the fine

aggregate is sand or surki and the binding material is lime or cement.

Fresh concrete or plastic is a freshly mixed material which can be

molded into any shape.

The relative quantities of cement, aggregates and water together control

the properties in the wet state as well as in the hardened state.

Constituents of Concrete

Cement

Fine aggregate and Coarse aggregate

Water

ADVANTAGES OF CONCRETE

It is plastic when freshly prepared and can be mounded to any

shape.

Concrete does not lose its strength with age and does not require

maintenance.

The proportion of mix can be suitable designed to give concrete of

required strength.

It is durable and not affected by weather.

It affords quickness and ease of a construction.

It can be given various finishes.

Concrete is water repellent and can be made water proof.

Concrete can be made fire proof or light weight or chemical resistant by

using suitable admixtures.

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PROPERTIES OF CONCRETE

Concrete has high compressive strength depends on the proportion of

cement, sand, coarse aggregates and water used.

It hardens with age and process of hardening continuous for long time

even after it has attained sufficient strength, but the rate of hardening

decreases with age.

It is free from corrosion and atmospheric effects.

It is weak in tension. Steel reinforcement is placed in cement concrete at

suitable places to take up the tensile stresses called as RCC.

It shrinks in the initial stage and during hardening. This can be minimized

by proper curing.

Segregation : Separation of the constituent materials of concrete

Bleeding : Water from the concrete comes out of the surface of the

concrete

Water Cement ratio: Ratio of weight of water used to that of cement. It

depends upon strength, workability and method of compaction

Workability

The property of freshly mixed concrete which determines the ease and

homogenous with which it can be mixed, placed, compacted and finished

Factors Affecting Workability

Water content

Mix proportions

Size of aggregates

Shape of aggregates

Surface texture of aggregates

Grading of aggregates

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Use of admixtures

WATER CONTENT

Water content in a given volume of concrete will have significant

influences on the workability.

Higher the water content, higher is the fluidity which affects workability.

Mix proportion

Aggregate/cement ratio is important factor influences workability.

Higher the aggregate/cement ratio, leaner is the concrete.

Size of aggregate

Bigger the size of the aggregate less is the surface area and less is the

amount of water.

It will give better workability.

Shape of aggregate

The shape of aggregate influences workability.

Angular, elongated or flaky aggregate makes the concrete harsh when

compared with rounded aggregates.

Surface texture

The total surface area of rough textured aggregate is more than the

surface area of smooth rounded aggregate of same volume.

Grading of aggregate

It influences maximum workability.

Better the grading, less the void content and higher the workability.

Use of aggregate

Use of air-entraining and pozzolanic material gives better workability.

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The following tests are commonly employed to measure workability:

Measurement of workability

Slump test – K Slumper

Compacting factor test - Compacting factor apparatus

Flow test – Flow table

Kelly ball test – Kelly ball

Vee bee consistometer test- VBR

Process of manufacture of concrete

The various stages of manufacture of concrete are:

Batching

Mixing

Transporting

Placing

Compacting

Curing

Finishing

Batching

The measurement of materials for making concrete is known as

batching.

Volume batching – Gauge box

Weigh batching – weight machine

Mixing

Mixing of materials is essential for the production of uniform concrete.

There are two methods for mixing concrete:

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Hand mixing

Machine mixing.

Transporting concrete

Concrete can be transporting by a variety of methods and equipments.

Mortar pan

Wheel barrow, Hand cart

Bucket and Rope way

Truck mixer and Dumpers

Belt conveyors

Chute

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Skip and Hoist

Pumps and Pipeline

PLACING

Placing concrete within earth mould.

e.g.: foundation concrete for a wall or column.

Placing concrete within large earth mould or timber plank formwork.

e.g.: road slab and airfield slab.

Placing concrete in layers within timber or steel shutters.

e.g.: mass concrete in dam construction or construction of concrete

abutment or pier.

Placing concrete within usual from work.

e.g.: columns, beams and floors.

Placing concrete under water.

Compaction of concrete

Compaction of concrete is the process adopted for expelling the

entrapped air from the concrete.

Hand compaction:

Rodding

Ramming

Tamping.

Compaction by vibration

Internal vibrator (needle vibrator)

Formwork vibrator (external vibrator)

Table vibrator

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Platform vibrator

Surface vibrator (screed vibrator).

Compaction by pressure and jolting

Compaction by spinning.

Curing of concrete

Curing is the process of maintaining a satisfactorily moisture content and

favorable temperature.

The following are the curing methods:

Water curing

Membrane curing

Application of heat

Miscellaneous

Water curing

Water curing can be done in the following:

Immersion

Ponding

Spraying

Wet covering

Membrane curing

Bituminous compounds

Polyethylene

Waterproof paper

Rubber.

Application of heat

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The exposure of concrete to higher temperature can be done in the

following manner:

Steam curing at ordinary pressure

Steam curing at high pressure

Curing by infra-red radiation

Electrical curing.

Miscellaneous methods of curing

Calcium chloride is used as a surface coating or as an admixture.

Finishing

Finishing operation is the last operation in making concrete.

Surface finish can be grouped as follows:

Formwork finishes – centering work

Surface treatment

Applied finishes.

Miscellaneous Finishes : Non - Slip Finish, Coloured finish, Water

resistant floor finish

TESTS OF FRESH CONCRETE

Slump test

Kelly ball test.

TESTS ON HARDENED CONCRETE

Non-destructive testing-does not cause any destructive of the element.

Semi-destructive testing-cause negligible damage of the element.

Non-destructive testing:

Rebound hammer test.

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Ultrasonic pulse velocity test.

Semi-destructive testing:

Windsor probe test

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REBOUND HAMMER TEST

It consists of spring-controlled mass that slides on a plunger within

tubular housing.

When the plunger is pressed the spring controlled mass rebounds.

Depends on surface hardness of concrete.

Related to compressive strength.

The rebound is read on graduated scale and the value is designated as

“rebound number” or “rebound index”.

Uses:

It is used for estimating the compressive strength.

Establishing the uniformity of concrete.

Assessing the quality of one element of concrete in relation to another.

Limitations:

Results are affected by the angle of test, surface smoothness, and mix

proportion.

It is only suitable for close-textured concrete.

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TYPES OF CONCRETE

FRC

Composite material consisting of mixture of cement mortar and

discontinuous discrete, uniformly dispersed suitable fibers.

Types:

a) SFRC- steel fiber reinforced concrete

Normal density

Air-entraining

Polymer concrete

composites

Sulphur impregnate

concrete

Fibre reinforced

concrete(FRC).

Roller compacted concrete

Super plasticized

C

o

l

o

u

r

e

d

P

u

m

p

e

d

R

e

a

d

y

Ferro cement

Light weight

Recycled

Heavy weight

No slump

No fine

Vacuum

Spanned

Hot

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b) CFRC- carbon fiber reinforced concrete

c) GFRC- glass fiber reinforced concrete

d) HFRC- hybrid fiber reinforced concrete.

SFRC- steel fiber reinforced concrete

Made up of rusted steel.

Used in road pavements, bridge decks.

CFRC- carbon fiber reinforced concrete

Has high tensile strength.

Durability.

HFRC- hybrid fiber reinforced concrete

Made up of polypropylene, nylon fibers, asbestos.

Durability

High tensile strength.

CFRC- carbon fiber reinforced concrete

Has high tensile strength.

Durability.

HFRC- hybrid fiber reinforced concrete

Made up of polypropylene, nylon fibers, asbestos.

Durability

High tensile strength.

Quality of concrete

Good workability

No segregation

No bleeding

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High strength

Durability

Impermeability

Elasticity

Shrinkage

Least thermal expansion.

Advantages of concrete

Availability of concrete is easy.

Easy handling.

Easy transportation.

More economical.

Monolithic character gives better appearance.

Disadvantages of concrete

Expansion joints are required.

Construction joints are provided to avoid cracks.

Sustain loads develops creep in structure.

Due to low tensile strength, concrete is required to be reinforced to

avoid cracks.

Soluble salts in concrete cause efflorescence of moisture react with

them.

CONCRETE CHEMICALS

They are used in cement as an additive, in mortar and concrete as

admixtures.

Such additives and admixtures are called as concrete chemicals or

construction chemicals.

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It includes the following materials:

Plasticizers and super plasticizers.

Retarding plasticizers and retarders.

Accelerating plasticizers and accelerators.

Air-entraining agent.

Water proofing material.

Polymer bonding agents.

Floor hardness and dust proofers.

Concrete curing compounds.

Polymer mortar for repair and maintenance.

Adhesive for tiles, marbles and granite.

Mould releasing agents.

Grouting agents.

Decorative and protective paint.

Concrete repair system.

Installation aids.

Queries

Two marks:

What is cement and list out its chemical composition?

What is the process of cement manufacturing?

What are the methods of testing in cement?

What is meant by workability?

What is concrete and explain mix proportion of concrete?

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What are the testing methods involved in fresh concrete and hardened

concrete?

What are the qualities of concrete?

Describe the advantage of concrete?

Describe the disadvantages of concrete?

What is meant by concrete chemicals?

16 marks:

Describe the manufacturing of cement (dry and wet process)?

What are the different types of cement? Explain their properties

and uses?

Describe the field testing and laboratory testing method in cement?

Explain in detail the process of concrete manufacturing?

Explain the method of non-destructive testing in detail?

What tests are used to determine the workability of fresh concrete?

explain in detail:

What are the different types of concrete? Explain their properties

and uses?

Explain the various types of concrete chemicals in detail?

Documents

STAR LION COLLEGE OF ENGINEERING AND TECHNOLOGY,