concreting works

8/17/2019 Concreting Works

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Quality Control

for

Concrete Works


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Contents

1. What is Quality

2. Importance of Quality

3. Stages of Quality Control in Concrete Works

a) Pre Pour Stage

b) During Pour Stage

c) Post Pour Stage

4. Responsibilities


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What Is Quality

What is Quality

The term “QUALITY” has been defined as the totality

of features and characteristics of a product or services

that bear on its ability to satisfy stated or implied

needs.


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What Is Quality

What is Quality Assurance

All those planned and systematic actions necessary to

provide adequate confidence that a product or

service will satisfy given requirements for quality.

It usually requires a continuous evaluation of factors

that affect the adequacy of the design or specificationfor intended applications, verifications and audits of

production, installation and inspection operations and

adequate documentation.


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What Is Quality

What is Quality Control

The operational techniques and activities that are

used to fulfill requirements for quality.

These Operational techniques are defined in quality

assurance stage


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Importance of Quality

Why do we need Quality in Construction

The most essential aspects in any construction are to

achieve-

o Strength

o Serviceability &

o Durability


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So to attain these aspects of construction we should

follow some set of norms as prescribed through

specifications, standards, codes of practice, standard

construction practice etc…

To avoid any delay or reworks which requires Moneyand Time which are very vital for a contractor


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Structures can stand with good quality construction

even though there is marginal deficiency in design

But

Good design cannot prevent failure of structures if

the construction quality is poor


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Stages of Quality Control in Concrete Works


a) Pre Pour Stage

b) During Pour Stage

c) Post Pour Stage


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Pre Pour Stage

Pre Pour Stage

To eliminate any undesired results after concreting

following norms are to be followed before starting

any concreting…


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Pre Pour Stage

Pre Pour Stage

Ensure all approvals for construction, IFC drawings, Safety

Norms, Work Method Statements are in place before starting

any activity at site.


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Pre Pour Stage

Pre Pour Stage

Before starting any new

activity all concerned persons

should be made familiar with

the sequences of activities to

complete the work in safe &

proper way with optimumutilization of resources by the

way of toolbox talks.


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Pre Pour Stage

Pre Pour Stage

Ensure all prerequisites like termite control, Screed concrete

waterproofing works are completes and signed off from

consultant to proceed further stage of work.


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Coordinate Making

Mark coordinates, grid

lines, opening and

element dimensions,

on the screed concrete

before starting fixing

of rebars as per IFC.


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Pre Pour Stage

Rebar Works

Ensure rebars are fixed

as per Bar Bending

Schedule or shop

drawing with proper

cover, extra bars as per

general reinforcementdrawings,


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Pre Pour Stage


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Pre Pour Stage

Rebar Works

Use proper supporting

system to support

vertical rebars in place

Proper platforms shall

be used for fixing of reinforcement


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Pre Pour Stage

Formwork

Formwork shall be

fabricated as per

approved formwork

details with all

accessories fixed in

position as permanufacturer

recommendations


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Pre Pour Stage

Formwork


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Pre Pour Stage

Formwork

Apply uniformly approved

Form releasing agent toshutter before fixing in

position


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Pre Pour Stage

Formwork

Tie rods must be provided exactly in same number and

position as per manufacture recommendations

Cones and sleeves used in tie rod are be sealed perfectly with

masking taps as this is most vulnerable for leakage.


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Pre Pour Stage

Formwork


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Pre Pour Stage

Formwork

All Joints are to be

properly sealed with foamsheet to prevent any gout

loss


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Pre Pour Stage

Formwork

Adequate support shall

be provided to supportthe formwork in position

and avoid bulging


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Pre Pour Stage

Formwork

After completion of

shuttering in all respectsformwork should be

checked for alignment

plumb, dimension, cover

and inserts if any.


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Pre Pour Stage

Formwork

Proper scaffoldings and

platforms shall beprovided to place the

concrete, so that no

workers will use the form

work as platform forconcreting


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Pre Pour Stage

Formwork

Construction activities are to be inspected by QC Engineer

during execution and suggest for any corrections

Before starting concreting activates works are to be cleared by

MEP and approving authority


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During Pour Stage

Concreting Activities

Clean the area ready for

concrete prior to concreteby air jet and ensure area

is clean and dry before

concrete


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During Pour Stage


o Ensure adequate equipment like viberator trowels screeds

etc., are available before starting concrete activities .o Only trained Forman and works should be engaged for

concrete operations.

o Sufficient number of carpenters must be available for

checking and tightening the tie rods.o Ensure adequate curing facilities are available before

starting concrete.


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During Pour Stage



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During Pour Stage


o Ensure concrete is done from height of 1.5 m. grater height may

lead to honeycomb and segregation.o Concrete must be done in layers in not more than 600mm in

height.

o Either sides of the opening shall be equally filled and vibrated to

prevent dislocation of formwork at openings.

o Correct concrete slump must be ensured to prevent

honeycombing and segregation.

o excessive vibration will lead to bleeding of concrete and disturb

the stability of form work to greater extent.


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During Pour Stage



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During Pour Stage



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During Pour Stage


o The carpenters must be slightly hammering the forms with rubber

mallets during concrete to obtain a smooth surface.o The concrete pour rate must not exceed the formwork design

criteria

o Any addition of water in concrete transit mixer for workability

should be strictly restrained. Such act shall lead to segregation of

concrete and result in excessive honeycombs

o For the areas where reinforcement congestion is encountered it is

recommended to use self-compacting concrete rather than

vibrating the normal concrete excessively


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Post Pour Stage

Post Pour Stage

o Check plumb for vertical elements and adjust if necessary

while concrete is still green.o Curing must commence immediately using water/ approved

curing compound.

o Any minor deformities / honey-combings observed must be

immediately repaired as per approved repair methodologyand with approved repair material .


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Post Pour Stage

Post Pour Stage

Ensure shutter are

properly cleaned oiledsoon after stripping for

further use


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Post Pour Stage

Post Pour Stage

Coordinates must be

checked and as built mustbe prepared to confirm

there is no deviation


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Responsibilities

QA/QC Engineer

o Check work under execution from time to time for any

corrective measures that may be required to avoid reworks.

o Rise NCR in the event of any deviations.

o Provide Tool Box Talks on all new activities to all concernedpersons to make them familiar with the sequences of

activities to complete the work in safe & proper way with

optimum utilization of resources.


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Responsibilities

Construction Manager

o Arrange material and man power for execution of works without

any hindranceo Provide toolbox talks to all concerned persons to make them

familiar with the sequences of activities to complete the work in

safe & proper way with optimum utilization of resources.

o Address all comments made by QC Engineer in preliminary

inspection prior to consultants inspection.o shall be thorough in all the IFC Drawings, shop drawings, Method

statement and normal construction practices etc.,


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Responsibilities

Project Manager

o Take corrective action immediately after receipt of internal

NCR.

o NCRs should be addressed / closed by all concerned within 3

days.

o In addition, preventive measures / Lesson learnt to be

implemented to avoid the recurrence.


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THANK YOU

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