concrete works (old one but could be used sometimes)

8/12/2019 Concrete Works (Old One but Could Be Used Sometimes)

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CONCRETEWORKS

1. OBJECTIVE

The main objective of this document is to provide guidelines for inspection of concrete works at

Construction of Canal Intake Structure: Project.

2. SCOPE

This method statement covers concrete works under the scope of project specifications and

Quality Management System (QMS) Companywide.

3. RESPONSIBILITIES

- The Construction Manager will organize resources to perform concrete works activities asper project specification, in compliance with quality, and planning schedule requirements.

- QCE will assure that all the relevant work is carried out in conformance with projectspecification, PQP and QIP. In case of any non-conformance, it will be controlled by

corrective action request (CAR).

4. PROCEDURE

4.1 Concrete Materials

4.1.1 Cement

- The cement used for concrete, reinforced concrete, mortar, grout & plaster worksshall be Portland cement conforming to project specs.

- The supplier/ manufacturer shall provide certificates of conformance. Use cement insequence of receipt of shipments unless otherwise directed by Client.

4.1.2 Aggregate (coarse & fine)

- Natural sand conforming to project specifications/codes shall be used.


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- The aggregates to be used in the concrete shall be procured from a source known toproduce aggregate that is chemically inert, strong, hard, durable and of limited

porosity and free from any adhering impurities that may impair the strength,

durability or quality 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. The equipment & method of handling the

aggregates shall ensure that the stockpiles do not suffer deterioration and

contamination.

4.1.3 Water

- The water used in the preparation of concrete & mortar shall be clean & free frominjurious amounts of impurities (Potable water meets this requirement).

4.1.4 Storage and Handling of Materials

- All materials shall be stored and handled in such a manner that will preventdamage or deterioration.

4.1.5 Concrete Additives/Admixtures

- Concrete additives/admixtures shall only be used after approval from theClient.

4.1.6 Mix Design/Trial Mixes

- Trial mixes shall be prepared to determine the mix proportions necessary toproduce the strength of concrete as per project specifications. Each mix

shall be prepared to meet the workability requirements for transporting,

placing & compacting of the concrete 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 be commenced

until formal approval has been received.


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4.2 Batching Plant

- The batching plant shall produce the concrete in accordance with the specific designmix applicable as per project specifications.

-

The Material Engineer/ Lab In-charge shall be responsible for determining thecorrect amount of water to be added keeping in view the moisture content of

coarse and fine aggregates and workability requirements as per project

specification.

- The batch plant controller shall be responsible for checking that all wash waterhas been removed from the delivery truck drum before adding new ingredients of

concrete.

- After loading fresh ingredients of concrete, the drum revolutions required toproduce uniform concrete shall be set.

- The batch plant technician shall perform the slump test and keep a complete recordof each truck of concrete.

- Calibration and inspection of the equipment of batching plant shall be carried outperiodically.

- Use of horn during movement of concrete trucks (if required).4.3 Hot weather concreting

- During hot weather the batching plant supervisor shall take all necessaryinstructions to ensure that the temperature of the mixed concrete does not exceed

specified temperature.

- These measures shall include, but not be limited to, shading of aggregates, sprayingwater on aggregates, linking the mixing water to a chilled unit, chilling the mix

ingredients with ice and when ice is used in the mix, maintain the correct amount of

water required.

- Re-tempering of concrete or mortar, which has partially hardened, shall not bepermitted.


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4.4 Concrete Tests

- The characteristic strength of the concrete placed in the formwork shall bedetermined for 7 days and 28 days by the compressive strength testing of test

cylinders as per project specifications.- Frequency for testing will be as per specs.- Keep a complete record of specimen of test concrete with location and date of

placement, proportion of mix blend and type of cement etc.

4.5 Concrete operations

4.5.1 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 stipulated time period after adding water.

- The concrete delivery note shall be endorsed with the time of dispatch ofthe truck. This information will also be summarized for each pour on

prescribed form.

- No concreting operations shall be performed without the written approvalof client.

4.5.2 Placing of Concrete

- Prior to placing concrete, air & concrete temperatures shall be recorded.- Placing of rebar and formwork shall be as per drawing and its get its

approval from client.

- All equipment that are necessary for placing concrete i.e. pumps, vibrators,compressors and concrete test equipment etc. shall be checked for

availability, operational capacity, reliability and calibration.

- For all large pours, prior to pouring, standby vibrators, concrete pumps,batching plants etc. shall be provided for replacement in the event of

breakdown.


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4.5.3 Compaction of Concrete

- During compaction, vibration checks shall be made to ensure that rebarspacer blocks are not displaced or dislodged. Rebar that shall be exposed

after concreting are protected during the pouring and subject to cleaning

during & immediately after the completion of the pouring.

- After placing, compaction shall be done thoroughly around allreinforcement, embedded fixtures and internal corners and forms with

internal vibrators according to the procedure conforming to project

specifications or standards.

- Use gumboots for entering into concrete.4.5.4 Concrete Curing

- Immediately after the concrete work has been accomplished, take measuresto protect the concrete by spraying the exposed surfaces with a curing

compound and by placing burlap or blankets. Cover the exposed surface by

hessian, these covers shall be maintained and where possible the burlap or

blankets shall be covered by polythene.

- Curing compound if used shall be approved by client and as per projectspecifications.

4.6 Concrete Finishing

- The concrete face shall be checked for compliance as indicated in the projectspecifications or construction drawings. The concrete face shall be clean and free

from all foreign matters etc.

4.7 Repairs to Damaged or Defective Concrete

- Follow the correct instructions so that concrete is not damaged or is not defective.- If some damage or defect exists, conduct inspection of the location jointly with

client/consultant and submit the proposed method statement for performance of

repairs and get it approved in writing before commencing such repairs.

4.8 Construction Joints

- Construction joints shall be constructed exactly in accordance with the detail shownin the plans and the specifications with the best of workmanship.


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- Get approval of client/consultant before introducing such joints if not shown on thedrawings.

- Time as per specs shall be elapsed 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 mortar before placing

new concrete.

4.9 Expansion Joints/Water stops

- Expansion joints shall be constructed as per drawings/specifications.- PVC/SS Water stops as required shall be fabricated and located as shown on the

drawings.

- Water stops shall be accurately cut, fit and integrally jointed at sectional joints andangular junctions to provide a continuous watertight diaphragm at all points.

- Make adequate provision for the support of water stops during the progress ofwork.

4.10 Concrete Embedment

- Anchor bolts, edging angles and other miscellaneous metal embodiments inconcrete shall accurately be located and secured in position within approved

tolerance to resist loads incidental to placing of concrete.

- Verify all anchor bolts and embedded items locations are as per constructiondrawings.

4.11 Equipment Installation

- Equipment shall not be installed till assurance of concrete strength.4.12 Hand finishing

- In the event of breakdown of mechanical equipment, hand-finishing method may beused to finish the concrete already deposited when the breakdown occurs and no

additional concrete shall be placed until such equipment is repaired to the

satisfaction of Client.

5. TOOLS & EQUIPMENTS

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


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6. Related documents

- Corrective Action Request (CAR) form- Quality of Coarse/Fine aggregate.- Survey Report- Weather record- Flat and elongated particles- Calculation Sheet Aggregate Combination For Concrete Design Mix.- Specific gravity test- Cement Soundness test- Unit weight (Loose / Rodded)- Summary of Daily Concrete- Concrete compression test- Monthly / Weekly summary of compression strength of concrete- Request/Report for Inspection/Test (RIT)


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concrete works (old one but could be used sometimes)

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