qa&qc_ms_ concrete work.docx

7/28/2019 QA&QC_MS_ Concrete Work.docx

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METHOD STATEMENT

FOR

CONCRETEWORK

Rev. No. Details Of Revision Date Prepared by Checked by Approved by

1. OBJECTIVE


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The objective of this method statement is to provide guidelines for inspection ofconcrete work at all Projects.

2. SCOPE

This method statement covers concrete works under the scope of projectspecification and Integrated Management System.

3. REFERENCES

The following documents are considered as reference document:

Applicable codes and standards

Project specifications

Project Quality Plan

Quality Inspection Plan

Project Drawings

4. ABBREVIATIONS/DEFINATIONS

5. RESPONSIBILITIES

The area incharge will organize resources to perform concrete worksactivities as per project specification, in compliance with quality, schedule &

HSE requirements.

QA&QC inspector will assure that all the relevant work is carried out inconformance with project specification, PQP and QIP. In case of any non-conformance, it will be controlled by corrective action request (CAR).

6. PROCEDURE

6.1 Concrete Materials

6.1.1 Cement

The cement used for concrete, reinforced concrete, mortar, grout& plaster works shall be Portland cement conforming to project

specification.

The supplier/ manufacturer shall provide certificates ofconformance. Use cement in sequence of receipt of shipmentsunless otherwise directed by consultant/client.

6.1.2 Fine Aggregates

Natural sand or sand prepared from stone, gravel or other inertmaterial having similar characteristics, conforming to projectspecifications/codes shall be used.

6.1.3 Coarse Aggregates

The aggregates to be used in the concrete shall be procured froma source known to produce aggregate that is chemically inert,strong, hard, durable and of limited porosity and free from any


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adhering impurities that may impair the strength, durability orquality of concrete.

Sampling and testing of coarse aggregate. Each size of the aggregate shall be stored separately and in a

manner that will prevent contamination and intermixing. Theequipment & method of handling the aggregates shall ensure thatthe stockpiles do not suffer deterioration and contamination.

6.1.4 Water

The water used in the preparation of concrete & mortar shall beclean & free from injurious amounts of impurities (Potable watermeets this requirement). The water shall conform the projectspecification/ACI code requirements. The water shall be stored ina clean container or tank and shall be subjected to chemicalanalysis as per specifications.

Sampling and testing of Rebar by independent lab.

6.1.5 Storage and Handling of Materials

All materials shall be stored and handled in such a manner thatwill prevent damage or deterioration.

6.1.6 Concrete Additives/Admixtures

Concrete additives/admixtures shall only be used after approvalfrom the Construction Manager.

6.1.7 Mix Design/Trial Mixes Trial mixes shall be prepared to determine the mix proportions

necessary to produce the strength of concrete as per projectspecifications. Each mix shall be prepared to meet the workabilityrequirements for transporting, placing & compacting of theconcrete relative to the particular situation it is to be used.

The details of the design/proposed mixes shall be submitted to theclient/consultant for his approval and no concreting shall becommenced until formal approval has been received.

Preparation of mix design and its approval

6.2 Batching Plant

The batching plant shall produce the concrete in accordance with thespecific design mix applicable as per project specifications.

The laboratory Incharge shall be responsible for determining thecorrect amount of water to be added keeping in view the moisturecontent of coarse and fine aggregates and workability requirementsas per project specification.

The batch plant supervisor shall be responsible for checking that allwash water has been removed from the delivery truck drum beforeadding new ingredients of concrete.

After loading fresh ingredients of concrete, the drum revolutionsrequired to produce uniform concrete shall be set.

The batch plant inspector/Quality Control man shall perform the slumptest and keep a complete record of each truck of concrete.


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Calibration and inspection of the equipment of batching plant shall becarried out periodically.

Use of horn during movement of concrete trucks (if required).6.3 Hot Weather Concrete

During hot weather the batching plant supervisor shall take allnecessary instructions to ensure that the temperature of the mixedconcrete does not exceed specified temperature or 40oC.

These measures shall include, but not be limited to, shading ofaggregates, spraying water on aggregates, linking the mixing water toa chilled unit, chilling the mix ingredients with ice and when ice is usedin the mix, maintain the correct amount of water required.

Re-tempering of concrete or mortar, which has partially hardened,

shall not be permitted.

6.4 Concrete Tests

The characteristic strength of the concrete placed in the formworkshall be determined for 7 days and 28 days by the compressivestrength testing of test cylinders/cubes as per project specifications.

On each day when concrete is poured a minimum of six tests

cylinders/cubes shall be produced from the same batch and for every100 m3 thereafter of as per specifications.

Keep a complete record of specimen of test concrete with locationand date of placement, proportion of mix blend and type of cementetc.

6.5 Concreting Operations

6.5.1 Transportation

Use of horn for starting a movement.

The concrete shall be transported to site in transit mixers

immediately after mixing and shall be placed within 30 minutes ofthe water being added.

The concrete delivery note shall be endorsed with the time ofdispatch of the truck.

The concrete pour record shall be endorsed with the time of arrivalof dispatch and at the time of completion of discharging.

The drum revolution counter shall be observed when the truckarrives at the pour site and after discharge and record bothreadings.

No concreting operations shall be performed without the writtenapproval of client/consultants.

6.5.2 Placing of Concrete


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Prior to placing concrete, air & concrete temperatures shall berecorded.

Placing of rebar and formwork shall be as per drawing and its getits approval from client.

All equipment that are necessary for placing concrete i.e. pumps,vibrators, compressors and concrete test equipment etc. shall bechecked for availability, operational capacity, reliability andcalibration.

For all large pours, prior to pouring, standby vibrators, concretepumps, batching plants etc. shall be provided for replacement inthe event of breakdown.

6.5.3 Compaction of Concrete

During compaction, vibration checks shall be made to ensure thatrebar spacer blocks are not displaced or dislodged. Rebar thatshall be exposed after concreting are protected during the pouringand subject to cleaning during & immediately after the completionof the pouring.

After placing, compaction shall be done thoroughly around allreinforcement, embedded fixtures and internal corners and formswith internal vibrators according to the procedure conforming toproject specifications or standards.

Use gumboots for entering into concrete.

6.5.4 Concrete Curing Immediately after the concrete work has been accomplished, take

measures to protect the concrete by spraying the exposed surfaceswith a curing compound and by placing burlap or blankets. Coverthe exposed surface by hessian, these covers shall be maintainedand where possible the burlap or blankets shall be covered bypolythene.

Curing compound if used shall be approved by consultant/clientand as per project specifications.

Incharge Quality Control shall keep curing records.

6.6 Concrete Finishing

The concrete face shall be checked for compliance as indicated in theproject specifications or construction drawings. The concrete faceshall be clean and free from all foreign matters etc.

6.7 Repairs to Damaged or Defective Concrete

Follow the correct instructions so that concrete is not damaged or isnot defective.

If some damage or defect exists, conduct inspection of the locationjointly with client/consultant and submit the proposed methodstatement for performance of repairs and get it approved in writingbefore commencing such repairs.

6.8 Construction Joints


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Construction joints shall be constructed exactly in accordance with thedetail shown in the plans and the specifications with the best ofworkmanship.

Get approval of client/consultant before introducing such joints if notshown on the drawings.

At least 48 hours shall elapse before casting adjoining concrete.

Construction joints shall be perpendicular to the plane of the member.

Continue all specified reinforcement through joints.

Joints should be roughened.

Construction joints shall be cleaned and grouted with cement mortarbefore placing new concrete.

6.9 Expansion Joints/Water stops

Expansion joints shall be constructed as per drawings/specifications.

Water stops shall be fabricated and located as shown on thedrawings.

Water stops shall be accurately cut, fit and integrally jointed atsectional joints and angular junctions to provide a continuouswatertight diaphragm at all points.

Make adequate provision for the support of water stops during theprogress of work.

6.10 Concrete Embedment

Anchor bolts, edging angles and other miscellaneous metalembodiments in concrete shall accurately be located and secured inposition within approved tolerance to resist loads incidental to placingof concrete.

Verify all anchor bolts and embedded items locations are as perconstruction drawings.

6.11 Equipment Installation

Equipment shall not be installed till the approval of concrete strengthby client / consultant.

6.12 Hand finishing

In the event of breakdown of mechanical equipment, hand-finishingmethod may be used to finish the concrete already deposited whenthe breakdown occurs and no additional concrete shall be placed untilsuch equipment is repaired to the satisfaction of engineer.

7. TOOLSANDEQUIPMENTS

Batching plant, Concrete Mixers, Transit mixers, Loader (front end), VibratorsConcrete pumps, Wheel-barrows etc.

8. HSEINSTRUCTIONS


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Concrete work shall be performed in accordance with relevant project HSEinstructions & HSE policy of DESCON at all temporary and permanent sites.

All efforts shall be made to keep the environment clean.

Material or equipment should be maintained in an orderly manner and labeledin accordance with statutory requirements and use in safe manner.

Concrete placing to be allowed only after Client approval.

Beware from falling or flying concrete while pouring is in progress.

If buckets are used for pour, riding the bucket is prohibited.

Electric powered trowels, floats & vibrators shall be double insulated orgrounded for operator protection.

Any liquid fuel spills and accidental waste disposal should be avoided andproperly cleaned up.

Nozzle-men must use PPE for head & face protection.

Eye protection required for labour area placing concrete.

9. RELATEDDOCUMENTS

qa&qc_ms_ concrete work.docx

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