SCHEDULE 3

THE TECHNICAL SPECIFICATION

FOR

The Piling Work

(Contract No. TMN/C/10/2011- )

CUDDALORE 2×600MW ITPCL POWER PROJECT

STANCARD TECHNICAL SPECIFICATION AND

INSTRUCTION FOR CONSTRUCTION AND

INSTALLATION OF RCC BORED CAST-IN-SITU ILES

INDEX OF CONTENTS

1. INTRODUCTION

2. SCOPE

3. GENERAL

4. CODES AND STANDARDS

5. COMFORMITY WITH DESIGN

6. MATERIAL

7. STORAGE OF MATERIALS

8. EQUIPMENT AND ACCESSORIES

9. INSTALLATION

10.TESTING AND ACCEPTANCE CRITERIA

11. TECHNICAL SPECIFICATION FOR PILING

12.SAFETY

1. INTRODUCTION

The Pile is the main and basic part of the foundation. Pile finds application in

foundation to transfer loads from a structure to competent sub-surface strata

having adequate load bearing capacity. This specification deals with bored cast-in-

situ piles. Bored cast-in-situ pile is formed within the ground by excavating or

boring a hole within it, withor without the aid of a temporary casing (to keep the

hole stabilized) and subsequently filling it with plain or reinforced concrete. These

piles are particularly applicable in certain subsoil condition where penetration to a

pre-determined depth is essential. Piling construction needs following mile stone

for better completion.

2. SCOPE

This specification deal with the requirements regarding materials, workmanship

and installation of bored cast-in-situ reinforced concrete piles of 2X600 MW

Thermal Power Project in Cuddalore District, Tamil Nadu State.

IS: 2911 (Part-1/Sec-2) shall form a part of this specification and shall be complied

with unless there are any variances with the specification where the latter shall

prevail.

3. GENERAL

The work to be provided by the sub-contractor, unless otherwise specified, shall

include but no be limited to the following:

3.1 furnish all labour, supervision, services, materials, equipment and accessories

, tools, plants transportation including consumables and temporary works

required for the supply and installation of piles of desired capacity.

3.2 Mark the proposed sequence of installation on seven copies of identification

plan. The identification plan will be prepared by the cub-contractor as per

the basic plan furnished by the Engineer, in so desired by him.

3.3 Contractor shall be furnished full detail of the proposed piling equipment,

accessories, temporary works and method of pile construction for approval

of the engineer.

3.4 Contractor shall submit detailed daily report of boring and pile casting

incorporating information as required by the Engineer.

3.5 Contractor shall be Carryout load test to the satisfaction of the engineer

including casting and submit the test results in approved proforma.

4. CODES AND STANDARDS

Reference to any code shall always reference to the latest revised edition of the

code including all its amendments upto date, unless otherwise specified. In the

event of any conflict between the requirements of this specification and those of

the referred codes, the former shall govern.

The Piling operation shall be carried out strictly in line with IS: 2911 (Part I/Sec. 2).

Major clauses are reproduced herein for purpose of ready reference and guidance

only. In case of any typographical errors & mistakes, the corresponding reference

in IS: 2911 (Part I/Sec. 2) shall prevail.

IS : 383 - Indian Standard Specification for Natural Sources for Concrete

IS : 432 - Indian Standard Specification for (Part-1) Mild Steel & Medium

Tensile Steel Bars and Hard drawn Steel Wire for Concrete

Reinforcement : Pat-1 Mild Steel and Medium Tensile Steel

Bars.

IS : 456 - Indian Standard Code of Practice for Plain and Reinforced

Concrete.

IS : 516 - Indian Standard Specification for Methods of Test for Strength

of Concrete.

IS : 1199 - Indian Standard Specification for Methods of Sampling and

Analysis of Concrete.

IS : 1786 - Indian Standard Specification for high strength deformed steel bars

and wires for concrete reinforcement.

IS : 2062 - Steel for General Structural Purposes.

IS : 2386 - Indian Standard Specification for Methods of Test for Aggregates

for Concrete Part – 1 to VIII

IS : 2502 - Code of Practice for Bending & Fixing of Bars for Concrete

Reinforcement.

IS : 2751 - Code of Practice for Welding of Mild Steel Bars used for

Reinforced Concrete Construction.

IS : 2911 - Code of Practice for Design and Construction-(Part-1/Sec.2) of Pile

Foundations-Bored Cast-in-situ piles.

IS : 2911 - Code of Practice for Design and Construction-(Part-1/Sec.2) of Pile

Foundations-Load Test on pile.

IS : 4926 - Indian Standard Specification for Ready Mixed Concrete.

IS : 9716 - Guide for Lateral Dynamic Load Test on Piles.

5. CONFORMITY WITH DESIGN

The sub-contractor will prepare check lists in approved proforma which will be

called “Pile Installation Cards”. At each important stage of the work as decided by

the engineer, the work will be checked and approved by the engineer for

correctness and conformity with the design, specification and drawings, before

allowing the next phase of work to commence. The intermediate checks and

approvals by the engineer will not, however, absolve the sub-contractor form his

total responsibility to execute the work as per the specification and drawings and

to remove and/or rectify all work which is defective or inaccurate.

6. MATERIAL

6.1 General

All materials viz. cement, steel, aggregates, water, etc. whether incorporated in the

works of used temporarily as aids or for executing enabling works will be of best

approved quality conforming to the latest Indian Standard Specification.

6.2 Casing

Casing in boreholes where used, should be manufactured out of best quality mild

steel with proper treatment, the composition and thickness of the materials being

of special importance where they are likely to be in contact with harmful chemicals

and organic materials causing deterioration in service.

6.3 Concrete

Concrete of M-30 grade shall be used for piles as indicated but the concrete

strength of pile should be higher than its design strength by 20% as a margin as

per drawings accordance with IS: 456. The concrete cube strength on 15 cm.

cubes at 28 days shall satisfy the acceptance criteria as per IS: 456. Concrete

cubes will be cast as per instruction of the Engineer. These will be cast and cured

by the sub-contractor at site for testing. The concrete shall be of such consistency

as to give a slump of 100 to 150 mm.Cement used for the concrete shall be

Ordinary Portland Cement of 4 grade conforming to IS: 1812 & 12269 respectively.

The minimum cement content shall be 400kg/M3 of concrete based on subsoil

condition requirement besides that required from strength and other

considerations.Clean water, free from acids and other impurities, shall be used in

the manufacture of concrete.

6.4 Reinforcement:

Reinforcement shall be mild steel bars conforming to IS: 432. If instead of mild

steel or steel bars are used they shall conform to IS: 1786 of Fe-500 grade.

7. Storage of Materials

7.1 General

All materials shall be stored so as to prevent deterioration or intrusion of foreign

matter and to ensure the preservation of their quality and fitness for the work, Any

material which has deteriorated or has been damaged or is otherwise considered

defective by the engineer shall not be used, failing which, the engineer shall be at

liberty to get the materials removed and the cost incurred thereof shall be realized

from the sub-contractor’s dues. The relevant clauses pertaining to storage of

material under “Technical Specification for Cement Concrete (Piling)” will apply.

7.2 Casing

Mild steel casing will be painted outside with two coats of anticorrosive paint or

smeared with protective layer of grease and kept store in weather proof sheds, off

the ground, on study racks in such a manner as to enable quick and easy in

spectrum. Epoxy painting on outside surface shall be provided if so specified in

the drawing.

7.3 Quality Control

The sub-contractor shall establish and maintain quality for different items of work

and materials as may be directed by the engineer to assure compliance with

contract requirements and maintain and submit to the engineer records of the

same. The quality control requirements stipulated under the “Technical

Specification For Cement Concrete(Piling)” will apply wherever relevant in

addition. The requirement will include but not be limited to the following:

a) Location and plumb: Control survey for accuracy in plan and check for

verticality.

b) Driving of casing: Correction of weight of hammer, length of fall, number of

strokes per minute and rate of penetration.

c) Boring: Boring method to suit soil profile.

d) Casting of pile: Check inside casing, reinforcement cage, concrete mix,

placing, consolidation and curing.

e) Inspection of pile.

f) Load tests.

8. EQUIPMENT AND ACCESSORIES

8.1 The equipment and accessories for installation of bored cast-in-situ piles shall

be selected giving due consideration to the subsoil conditions and the method of

installation, etc. These shall of standard type and shall have the approval of the

Engineer-in-charge.

8.2 The capacity of the rig shall be adequate so as to reach the desired depth.

8.3 Provision shall be kept for chiseling within the borehole in case of any

underground obstruction/hard strata. However, chiseling shall be carried out only

with the approval of Engineer-in-charge.

8.4 In case pile is required to be socketted in medium or good quality rock strata,

the equipment mobilized shall have adequate capability to do so upto the required

socket length.

8.5 Use of drilling mud in stabilizing sides of boreholes is also made where

appropriate or necessary. Drilling mud should have certain basic properties.

9. INSTALLATION

All installation requirements shall be in accordance with IS : 2911 (Part 1/Sec.2)

and as supplemented or modified herein or by other best possible standards

where the specific requirements mentioned in this section of the specification

might not have covered all the aspects to the fill satisfaction of the engineer.

9.1 General

The sub-contractor shall furnish complete information about the type of piles

offered with sketches of pile sections showing reinforcement, method of boring,

details and availability of equipment and accessories formula or data curve on

which the sub-contractor bases the load carrying capacity of piles as well as the

criteria for determining suitable and sufficient founding of individual piles and any

other relevant details.

The sub-contractor will be supplied with bore hole logs or any other data indicating

the nature of the soil expected to be encountered. The information furnished to the

sub-contractor shall be taken as guidance only and variation there from shall not

affect the terms of the contract. Piles should be founded on suitable continuous

hard strata. In case the sub-contractor is required to drive piles to greater of

shallower depths than that is envisaged the sub-contractor to do the same. The

sub-contractor should in his own interest, investigate the site thoroughly and take

additional bores if he feels it necessary to assess the type of boring equipment to

be used and the depth to suitable founding strata.

9.2 Identification of Piles.

A Plan in triplicate, showing clearly the designation of all piles by an identifying

system shall be filed with the engineer before installation of piles is started if so

desired by the engineer.

9.3 Sequence of Piling

Individual piles and pile groups shall be constructed in such a sequence that the

adjacent piles already installed are not disturbed, nor their carrying capacity

reduced by subsequent boring/driving operation. The Sub-Contractor should follow

the sequence order strictly to work that Engineer created.

9.4 Boring

9.4.1 With Casing

Boring equipment and accessories shall generally conform to IS 2911 –relevant

section. Boring may be done by either rotary or percussion equipment or grabbing

equipment using reversed or direct mud circulation method. In case of unstable

soils the boring tools used should be such that suction effects are minimized.

Stabilization of the sides of bore hole shall be done by use of casing. The size of

cutting tools shall not be less than the diameter of the pile by more than 75 mm.

The Casing should be used from the found level and shall be dept ahead of boring

in case where there is danger of caving-in due to subsoil water entering into the

bore hole or where the soil is loose. While boring below subsoil water level,

precaution shall be taken so that no boiling of the bottom of the hole occurs due to

difference in hydrostatic head.

Boring shall proceed by alternatively driving the casing and extracting the bored

material with the boring tools. While boring in soft material liable to cavitations

boring tools shall not be operated at a level below the toe of the casing. Care shall

be taken to ensure that the volume of water added to the bore shall be not more

than the minimum necessary for the operation of the boring tools. The casing shall

be driven down through the soft material to penetrate a hard stratum not subjected

to cavitations and shall be sealed in this material as far as possible. Thereafter the

boring shall be continued by means of the boring tools until the approved bearing

layer is reached.

Criteria for approval of the bearing layer will be agreed between the Engineer and

the Sub-contractor based on visual inspection of recognizable sample, recovered

from the pile bore in the upper levels of the compact layer. The approved samples

shall consist of sound material shall be consistent in quality for a depth of 300 mm

in the pile bore. A sample of this material shall be supplied by the Sub-contractor

to the Engineer duly labeled for maintaining records of the founding strata.

The piles shall be installed with due consideration for safety of adjacent structures

by a method which their strength unimpaired and which develops and retains the

required bearing resistance.

Where the soil is such that driving of a pile causes previously installed piles to

heave, load test shall be conducted at the expense of the Sub-contractor on such

proportion of the heaved piles which shall be ordered by the Engineer.

9.4.2 With Drilling Fluid.

Alternate to the boring with casing, stabilization of the sides of bore hole can be

effected by the use of drilling fluids.

In such cases the drilling fluid mist be used at least from the level of subsoil water,

as the hole, should then be always kept almost full with the fluid. The density and

composition of the fluid shall be such as to suit the requirements of ground

conditions and to maintain the fine materials from the boring in suspension. At the

last stage of boring or in intermediate hard layers chisel or a chopper may be

used. The rate for piling work should be inclusive of any chiseling, chopping of

hard strata, clearing of bottom of pile borehole etc complete as per specifications

and necessary penetration test as may be required to prove the soundness of the

founding strata. A five percent bentonite suspension would be generally suitable

and its quality shall conform to specification given in Appendix ‘A’ or IS : 2911

(Part-1/Sec.2).

9.5 Spacing of Piles.

In general, all piles shall have minimum spacing on centers of 3 d (where‘d’ is the

diameter of the pile) unless shown otherwise in the drawings.

9.6 Placing of Reinforcement

Reinforcement as required shall be made into stiff cages sufficiently wired or

welded to withstand handling without any damage or distortion. Reinforcement

shall be placed immediately after cleaning and inspection of the bottom of bore

holes. The reinforcement should be supported away from the sides of the shaft by

means of suitable space block to ensure concentric alignment in the shaft. Steps

shall be taken to ensure correct positioning during concreting of reinforcement in

the piles without and distortion.

Nominal lap between reinforcement cages shall be 60 cm and the main reinforcing

steel shall project for a length sufficient to develop bond (45 times the diameter of

reinforcing bar) above the level of the underside of the pile cap.

The concrete cover to main reinforcement shall not be less than 5 cm and suitable

spacer blocks shall be provided at intervals not exceeding 2 meters and wired to

the main reinforcement.

9.7 Concreting

Immediately before concreting the bottom of the hole shall be cleaned very

carefully. The cleaning of the hole shall be ensured by careful operation by air

lifting process unless otherwise allowed by the Engineer. To lift spoil at founding

level before concreting, borehole shall be agitated by jetting with fresh drilling mud

with relatively higher pressure than that used during boring or air through tremie

pipe. While boring by use of drilling mud, the specific gravity of the mud

suspension in the vicinity of the bottom of the borehole shall be determined by

suitable slurry sampler in a first few piles and at suitable interval of the piles and

recorded. Consistency of the drilled mud suspension shall be controlled

throughout the boring as well as concreting operation in order to keep the hole

stabilized and to avoid concrete mixed up with the thicker suspension of the mud.

Concreting of boreholes shall start as soon as possible after the completion of

boring. It a borehole, be left unconcerned for more than two hours, it shall be

cleaned thoroughly as directed by the Engineer before concreting. Concrete shall

be so placed as to fill the entire volume of the tube or bore without the formation of

voids caused by faulty consolidation or entrapped air. Great care shall be taken to

ensure that the fluid alluvial soil does not penetrate between batches of the

concrete. Concreting under water shall be done in one operation. Concrete shall

be placed by means of a tremie pipe. It shall, however, be ensured that concrete

entering the tremie pipe does not get mixed up with the slurry and ¼ kg of

granulated vermiculite shall be poured in the tremie pipe before pouring concrete

as directed by the Engineer.

9.7.1 Tremie Method of Concreting.

The tremie pipes and funnel shall be filled and lifted just 15 cm above bottom

before releasing the concrete column to facilitate flushing out the bottom. The

concrete levels in the tremie shall be checked every few centimeters in order to

not the difference. If any, between the theoretical quantities that should have been

placed and actual quantity that has gone in. This is to locate the position of over

cut during boring.

In addition to the normal precautions to be taken in tremie concreting as per

relevant section of IS : 2911 the following specification shall be particularly

applicable for the use of tremie concrete in pipes.

a) The concrete shall be coherent, rich in cement (not less than 400 kg/m3) and

of slump not less than 100 mm.

b) The hopper and tremie shall be closed system embedded in the placed

concrete, through which water cannot pass.

c) The tremie shall be large enough with due regard to the size of the aggregate.

For 20 mm aggregate the tremie pipe shall be of diameter not less than 200 mm,

aggregates more than 20 mm shall not be used.

d) The first charge of concrete shall be placed with a sliding plug pushed down

the tube ahead of it or with a steel plate of adequate charge to prevent mixing to

concrete and water. However, the plug shall not be left in the concrete as a lump.

e) The tremie pipe shall always penetrate well into the concrete with an adequate

margin if safety against withdrawal of the pipe is required while discharging the

concrete.

f) The pile shall be concreted wholly by tremie and the method of deposition

shall not be changed part way up the pile to prevent the laitance from being

entrapped within the pile.

g) All tremie tubes shall be scrupulously cleaned after use.

Normally concreting of the piles shall be uninterrupted in exceptional cases

interruption of concreting may be allowed but it will be resumed within 1 or 2

hours. The tremie shall not be taken out of the concrete, instead it shall be raised

and lowered slowly, from time to time to prevent the concrete around the tremie

from setting. Concreting should be resumed by introducing a little richer concrete

with a higher slump for taking care of the partly set concrete in te gore. If the

concreting cannot be resumed before final setting of concrete already placed, the

pile so cast may be rejected.

In case of withdrawal of tremie out of the concrete, either accidentally or to remove

a choke in the tremie, the tremie may be reintroduced in the following manner to

prevent impregnation of laitance or scum lying on the top of the concrete already

deposited in the bore.

The tremie shall be gently lowered on to the old concrete with very little

penetration initially. A vermiculite plug shall be introduced in the tremie. Fresh

concrete of slump between 150 mm and 175 mm shall be filled in the tremie which

will push the plug forward and will emerge out of the tremie displacing

laitance/scum. The tremie will be pushed further in steps making fresh concrete

sweep away laitance/ scum in its way. When tremie is buried by about 60 to 100

cm, concreting may be resumed.

9.7.2 Concreting in Cased Holes

In case of cased holes, after the required founding level is encountered, the

bottom shall be sealed with concrete and the reinforcement cage shall be lowered.

If the borehole is dry concrete shall be deposited by direct pour from the top

followed by gradual withdrawal of casings. If water is present in the borehole, it

shall be bailed out by bailer.

If it is difficult to dewater by the bailer, concrete shall be placed under water by

means of a placer. After the head of water has been neutralized by the head of the

concrete, excess water shall be bailed out and concrete shall then be deposited by

direct pouring from the top, as is done, if the borehole is dry.

Extraction of casing shall be done in such a way that no necking or shearing of the

concrete in the shaft takes place.

During the extraction of casing, slumping of concrete shall be observed and when

required, additional quantity of concrete shall be poured so that the pile is formed

above the cut-off level as per the requirements indicated below.

9.7.3 Cut-off Level

The top of concrete in a pile shall be brought above the cut-off level to permit

removal of all laitance and weak concrete before capping and to ensure good

concrete at the cut-off-level for proper embedment into the pile cap.

Where cut-off-level is less than 1.5 m below the working level concrete shall be

cast to a minimum of 500 mm above cut-off level. For each additional 0.3 m

increase in cut-off level below the working level additional coverage of 50 mm

minimum shall be allowed. Higher allowance may be necessary depending on the

length of the pile as directed by the Engineer. When concrete is placed by tremie

method, concrete shall be cast to the piling platform level to permit overflow of

concrete for visual inspection or to a minimum of one meter above cut-off level. In

the circumstances where cut-off level is below ground water level, the need to

maintain a pressure on the unset concrete equal to or greater than water pressure

shall be observed and accordingly length of extra concrete above cut-off level shall

be determined and allowed in works.

9.8 Steel Pipe or Casing tube

This item shall be fabricated with mild steel plates conforming to IS:2062 and/or

steel tubes for structural purpose conforming to IS : 1161 & IS :1239 as shown on

drawings and/or described in the schedule of items.

9.9 Trimming of Pile Heads

Completed piles shall be trimmed to the cut-off levels shown on the drawings or

until sound concrete is found to the satisfaction of the Engineer. In the event of

trimming being carried below the cut-off level, the pile shall be made upto the

correct cut-off level, with concrete of the same quality as used in the piles at the

Sub-contractor’s expense. Reinforcement shall be exposed for the full bond length

appropriate to the diameter of the bar and projected in the pile cap. The minimum

distance of keying of pile into pile cap shall be 75 mm unless noted otherwise. All

concrete and cement shall be removed from the bars, which shall also be wire-

brushed to remove any loose, rust, dirt and scale.

Manual chipping shall be permitted after three (3) days of pile casting, Pneumatic

chipping, if permitted by the Engineer, shall not be started before seven (7) days.

In case Portland Pozzolana cement is used, chipping shall only be started as

directed by the Engineer.

9.10 Lengthening of Piles

Where it is necessary to increase the length of any pile after it has been driven,

the head of the pile shall be cut-off to expose the reinforcement for a full bond

length of the bars to lap with the new bars. The exposed surface of the concrete

shall be hacked to form a key, brushed to remove loose material and covered with

25 mm thick cement mortar (1:2 mix) immediately before the new concrete is

placed.

9.11 Removal of Spoil

The Sub-contractor shall be responsible for the prompt removal from the site of all

spoil due to the boring to places indicated by the Engineer. The cost of such

disposal shall be deemed to have been included in the cost of piling.

9.12 Back-Filling of Abandoned Borings

The sub-contractor shall backfill all the abandoned borings between the concrete

pile and the surface level after setting of concrete of the piles, by sand or by other

materials as directed by the Engineer.

9.13 Record for Installation of Piles.

The Engineer and the Sub-contractor shall maintain separate registers, signed

jointly by both the parties, giving the following information for each pile or any

other proforma as agreed between Engineer and Sub-contractor. These data shall

be submitted to the Engineer, in triplicate, on completion of installation of each

pile.

a) Date of completion, pile number & sequence of installation of piles in a group.

b) Bored depth, concreted depth, empty boring and nature of stratum at founding

level.

c) Pile diameter, details of reinforcement and details of mild steel liner where

provided along with stiffener.

d) Volume of concrete poured, time taken, cement bag consumption, slump of

concrete and RL of top of concrete.

e) Time taken for penetration of every 15 cm during last 2 m depth before

founding level.

f) Method of cleaning bottom of hole at founding level before concreting.

g) Records of additional borings or other subsurface information obtained during

the process of boring.

h) Any other relevant important information.

Any sudden change in the rate of boring which cannot be ascribed to the nature of

the ground or any deviation from the designed location, alignment of load carrying

capacity of any pile or any upheaval or subsidence noticed on any pile shall be

promptly reported to the engineer and adequate corrective measures shall be

taken free of any charge as decided by the engineer.

The data for pile load test (load, displacement, time etc) are to be recorded

sequentially for the test under consideration in a suitable proforma as agreed

between Engineer and Sub-contractor. These data along with the load-

displacement curve shall be submitted to the Engineer, in triplicate, on completion

of each load test.

9.14 Defective Piles.

Any pile which is shown to be defective under load test shall not be

accepted and the Engineer will relate such failure to the

acceptance of other piles in the area. If an individual pile should fail

to meet the requirements specified in Clause 16.00.00 above such

piles may be deemed to be defective and the Engineer may order

such investigation to be made as he considers appropriate.

When any pile is found defective, the Sub-contractor shall perform

at his own expense one or more of the following remedial measures

(with in three days) as Indian Standred and approved by Engineer

and Owner Engineer.

a) Replacement of defective piles.

ii) Providing additional piles.

iii) Alteration in design of pile caps.

Sub-contractor will be liable for losses, if whole project activity

delay due to such defective task.

9.15 Idle Period

The phasing of construction and movement of plant shall be done as desired by

the engineer. The phasing may involve some extra movement of the plant or some

idle period, but the sub-contractor will not be entitled to any claim due to this

reason.

9.16 Test Pile

The phasing of construction and movement of plant shall be done as desired by

the engineer, before he starts systematic piling operation at locations indicated.

For this purpose, the pile construction process shall be the same as in usual piling

process to be followed on this job. Load test on such piles shall be as per the

provisions under “Procedure for Initial Load Test” in IS:2911 (part – IV) or as

directed by the engineer.

10. TESTING AND ACCEPTANCE CRITERIA

10.1 General

The sub-contractor shall carry out all sampling and testing in accordance with the

relevant Indian standards and as supplemented herein for the following items at

his own cost unless otherwise specified in the contract. Whenever directed the

sub-contractor shall get the specimens tested in a laboratory approved by the

engineer and submit to the engineer test results in triplicate within three (3) days

of completion of the test.

10.2 Components of RCC

The testing and acceptance criteria for components of reinforced cement concrete

shall be as stipulated in the relevant clauses of the Technical Specification for

Cement Concrete (Pilling Works.)

10.3 Components of Steel

Testing and acceptance criteria for the component of steel pile material and

fabrication work shall be as stipulated in relevant clauses of IS: 800 and IS :9595

10.4 Load Tests

10.4.1 General

Initial tests and/or routine tests as indicated in the schedule of items or as directed

by the engineer shall be carried out on single pile or pile groups to ascertain the

capacities of the piles and their behavior.

Any or all of the tests described below shall be carried out as indicated in the

schedule of items and as directed by the engineer. The tests shall be performed as

per requirements of the relevant Indian Standards and as supplemented herein.

10.4.2 Vertical Load Test [as per IS:2911 (Part - IV)]

Load tests shall be carried out on single piles to check the bearing capacity or the

quality of piles in the manner specified below.

From among the completed piles the Engineer at his discretion shall select piles

for the purpose of testing.

At least 1 % of the piles driven shall be tested to an overload of 50% above the

working load of the pile and 0.1% of the piles driven shall be tested to an over load

of 100% above the working load of the pile.

Load shall be applied in increments of about one-fifth of the design load till the

design load is reached and thereafter in increment of 10 tones till the test load is

reached.

Each increment of load shall be maintained for minimum of half an hour up to

design load and thereafter for one hour till the test load is reached. Test load shall

be maintained for 24 hours. For each increment of load, readings of settlement at

every ten minutes shall be taken. The nest increment of load shall be applied only

when the difference in settlement of readings of readings between the last two

readings does not exceed 0.02 mm. On application of test load, readings shall be

taken at every hour.

Unloading will be done in following decrements of load:

a) Test load to design load

b) Design load to 50% of design load

c) 50% of design load to 25% of design load

d) 25% of design load to complete unloading.

Each decreased load shall be kept for a minimum of half an hour and readings of

rebound taken every ten minutes. The nest decrement shall be applied only when

the difference in reading between the last two readings is less than 0.02mm.

The observation and recording of settlement and rebound shall be done

simultaneously by the sub contactor and the Engineer’s representative. Three

copies of all the readings for the test shall be supplied by the sub-contractor to the

Engineer-n-charge. Actual proforma for recording the results shall be proposed by

the sub-contractor and approved by the Engineer-n-charge before the start of the

load test.

The pile shall be deemed to be acceptable if the gross settlement at the test load

of one and a half times the designed load does not exceed 0.01” per ton of test

load or ½” (12mm) whichever is less.

In case a pile fails under or during the load test, the Engineer shall select two

additional piles in lieu of each of such piles failed and the sub-contractor shall

carry out load tests on these piles in the same way as the load tests on the original

piles at his own cost. This procedure will be repeated in the case of each failure of

pile under/during load test.

The sub-contractor shall arrange at his own expense sufficient amount of

knowledge for loading well in advance of the commencement of the load test.

Detailed proposal together with a sketch for the load test arrangement shall be

furnished by the sub-contractor to the Engineer-in-charge for checking and

approval.

The pile head shall be chipped off to natural horizontal plane till sound concrete is

met. The projecting reinforcement shall be cut-off or bent suitably and the top

finished smooth and level. A bearing plate with a hole at the centre shall be placed

on the head of the pile for the jacks to test.

Jacks used in any particular load test should be of the same capacity and their

number shall be limited to two only. They should preferably be connected and

operated by one pump. The sub-contractor shall submit certificates certifying the

correctness of the calibrations of the pressure garages and jacks before use. All

jacks should be fitted with locking devices. Settlement and rebound shall be

recorded by minimum two (2) deflectomenters of 0.01 mm sensitivity and also by

other independent means of direct measurement. Deflectometers shall be

supported independently and in such a way as to be not affected by the settlement

of the piles.

10.4.3 Lateral Load Test

The test shall be carried out by introducing hydraulic jack with gauge between two

piles under test or the reaction shall be suitably obtained otherwise. When the test

is conducted by jack located between two piles, the full load imposed by the jack

shall be taken as the lateral resistance of each pile.

Load shall be applied in increments of about one-fifth of the design load. The nest

increments shall be applied after the rate of displacement is nearer to 0.1 mm per

30 minutes. Displacement shall be read by using at least two (2) deflect meter of

0.01 mm sensitivity spaced by 30 cm and dept horizontally one above the other or

by any means as per IS:2911 (Part-4) or as approved by the Engineer. The safe

lateral load on pile shall be taken as the least of the followings.

a) Fifty percent (50%) of the final load at which displacement increases to 12

mm.

b) Final load at which the total displacement corresponds to 5 mm.

10.5.0 Non-destructive Dynamic Test on Working Piles.

10.5.1 “Low Strain” Method for Integrity Investigation of Concrete Piles.

The method of testing shall conform to ASTM D 4945.

All equipments e.g. small impact device 16 lbs. nylon tipped hand held hammer,

accelerometer, pile integrity tester & piles driving analyser shall be arranged by the

Sub-contractor. Analysis shall be carried out by exponential amplification of the

signal with time and the average velocity curve obtained by numerically integrating

the acceleration record to be submitted. From analysis of the results any defect

like necking, honeycombing, segregation or weakness in concrete, when detected

shall be reported in detail.

10.5.2 “High Strain” Method for Determining of pile Capacity.

The method of testing shall conform to ASTM D 4945. All equipment including

piezoelectric transducers, strain gauges, pile driving analyser, two track

oscilloscope for displaying data and analog tape recorders for recorders for

recording data shall be arranged by the sub-contractor. For every hammer below,

the analyser shall determine the following data.

a) Pile bearing capacity

b) Transferred energy

c) Maximum compression force

d) Maximum tension force

e) Maximum impact velocity

f) Maximum acceleration

g) Maximum displacement

Which are to be properly recorded and analysed and submitted in a detailed report

form.

10.6 ACCEPTANCE CRITERIA

The piles shall be accepted as satisfactory only when the work has been executed

in accordance with this specification to the satisfaction of the Engineer and the

standards stated hereinafter.

a) The head of the pile shall be within 75 mm of the specified position on the

drawings.

b) The pile shall not be out of plumb by more than two percent.

c) The toe of the pile shall be at the approved bearing level in each case.

d) The total volume of concrete shall not be less than 20% and not more than

50% greater than the calculated volume. The calculated volume for this purpose

shall be the cross-sectional area inside the casing multiplied by the length of the

shaft. The concrete shall show the specified strength as indicated by the cube test

results.

e) The results of the load tests incl. non-destructive dynamic test carried out in

accordance with the contract and with the specification shall be satisfactory.

f) In case of single pile the positional tolerance shall not be more than 50 mm.

10.7 Lateral Dynamic Load Test on Piles

Two types of tests namely, free and forced vibration lateral tests shall be carried

out to observe response of soil-pile system under horizontal dynamic loads and for

the evaluation of soil-pile stiffness, soil modulus, natural frequency time period and

damping characteristics of soil-pile system.

A minimum of three representative piles of same type in almost similar soil

conditions shall be tested. Two adjacent piles shall be subjected first to free

vibrations and then to forced vibrations, the third pile shall only be tested under

forced vibrations.

The equipment and accessories for the test, setting up and test procedure and

recording of observations shall be as described in relevant sections of IS:9716

(Guide for Lateral Dynamic Load Test on Piles). The tests shall normally be carried

out without sustained vertical load other than that of the oscillator assembly.

However, sustained weight can be used to increase dynamic force to obtain

resonance or nearly resonance condition.

From analysis of test data the following parameters shall be determined:

a) Frequency of vibrations

b) Amplitude of vibrations

c) Imparted dynamic force

d) Natural frequency

e) Damping coefficient

f) Soil-Pile stiffness

g) Coefficient of horizontal soil modulus variation

TECHNICAL SPECIFICATION FOR

QUALITY ASSURANCE OF PILING WORKS FOR 2X600 MW ITPCL PROJECTS

1. General Requirement

1.1 The pile foundation shall be of RCC, cast-in-situ bored, precast/cast-in-situ

driven pile as per IS: 2911 Bored piles shall be installed by using rotary hydraulic

rig.

1.2 The minimum diameter of pile shall be 600mm for cast-in-situ and pre-cast

piles. The uplift and lateral loads capacity shall be established by field test.

1.3 Only straight shaft piles shall be used. Minimum cast length of pile above cut-

off level shall be 1.0 m.

1.4 The piling work shall be carried out in accordance with IS: 2911 (Relevant

part) and accepted construction methodology. The construction methodology shall

be submitted by the Bidder for Contractor’s approval.

1.5 Number of initial load test to be performed for each diameter and rated

capacity of pile shall be as inder:

Vertical

Lateral Minimum of 3 Nos. in each mode

Uplift

The initial pile load test shall be conducted with test load up to three

times the estimated pile capacity. In case of compression test the

method of loading shall be cyclic as per IS: 2911 (relevant part)

a) Number of routine pile load tests to be performed for each

diameter/allowable capacity of pile shall be as under:

i) Vertical - 0.5% of the total number of piles provided.

ii) Lateral - 0.5% of the total number of piles provided.

The routine tests on piles shall be conducted upto test load of one and

half times the allowable pile capacity. The Contractor shall approve piles

for routine load tests. Routine load tests may be done by conventional

method as per IS: 2911 (Part-4) or by means of high strain dynamic pile

load testing method as per ASTM D4945. If high strain dynamic pile

load testing is adopted, site specific correlation vis-à-vis conventional

test shall be established as approved by Owner/Engineer.

In case, routine pile load test shows that the pile has not achieved the

desired capacity or pile (s) have been rejected due to any other reason,

then the Sub-Contractor shall install additional piles(s) as required and

the pile cap design shall accordingly be reviewed and modified, if

required, without additional cost to the Contractor.

1.7 Testing of piles and interpretation of pile load test results shall be carried out

as per IS: 2911 (Part-4). Sub contractor shall ensure that all the measuring

equipment and instruments are properly calibrated at a reputed laboratory institute

prior to their use. Additional measurement for pile movement shall also be done.

1.8 Low Strain pile Integrity test shall be conducted on all test piles and job piles.

This test shall be used to identify the piles for routine load test and not intended to

replace the use of static load testing.

1.9 Pile installation equipment suitable for flushing with air lift technique shall be

used for construction of bored piles.

1.10 Minimum grade of concrete shall be M-30 grade, with minimum cement

content of 400kg/cum. Maximum free water cement ratio is 0.5. The concrete shall

be of such consistency as to give a slump of 100 to 150 mm.

1.11 Concreted pile shall not be loaded for testing or for pile cap construction at

least for a minimum period of 4 weeks.

2. Quality Assurance Requirements for RCC Piles (Part-1) – Bored Cast-in-situ

Piles.

2.1 Standard Penetration Test (SPT) as per IS-2131 and contractor technical

specification for determining the founding level of piles.

2.2 Uniaxial Compressive Strength (UCS) test shall also be performed on Fock

Cores. In case it is not possible to test the cores so obtained for Uniaxial

Compressive Strength, core shall be tested for point load strength index and

correlated to obtain Uniaxial Compressive Strength.

2.3 Founding level of the piles shall be decided based on the criteria given in

contractor’s Technical Specification.

2.4 Check for control of position and alignment of piles as per IS-2911(Part

-1/Sec-2)

2.5 Boring & Drilling : Drilling mud shall be tested of the following:

2.5.1 Liquid limit of drilling mud (Bentonite Slurry) as per IS-2720 Part V.

Acceptance criteria shall be as specified in Contractor’s Technical Specification.

2.5.2 Sand content of Bentonite powder.

2.5.3 Density of freshly prepared Bentonite suspension shall be checked in each

pile bore before concreting.

2.5.4 Marsh viscosity

2.5.5 Differential free swell index

2.5.6 pH value of Bentonite suspension

Properties of drilling mud shall be checked prior to commencement of the piling

work and thereafter, min once per week or as found necessary by contractor’s

engineer. One sample consisting of 3 specimens shall be tested for above.

2.6 Check cleaning of pile bore.

2.7 Concreting. All the checks/tests on concrete and concrete material shall be

carried out as per FQP and IS- 2911 Part-1/Sec-2

2.7.1 Before starting concreting the contaminated drilled mud at the (Slurry

collected in sampler tube) bottom of pile bore shall be tested for density and sand

content. Density should not be more than 1.25T/Cum.

2.7.2 For Working piles: Minimum one sample consisting of 6 test cubes shall be

made for first ten piles. Out of these 3 shall be tested for 7 days cube strength and

3 for 28 days cube strength. Minimum one sample of 6 test cubes for every 25

Nos. of piles shall be tested, out of these 3 shall be tested for 7 days cube

strength and 3 for 28 days cube strength.

2.8 Reinforcement bars used for piles shall be of tested for quality and conform to

the requirements of relevant IS codes.

2.8.1 Check distance between two adjacent main reinforcement bars and should

be as specified in Contractor’s Technical Specification.

2.8.2 Check proper cover and central placement of reinforcement cage in the pile

bore by suitable concrete spacers/rollers. Check minimum clear cover to

reinforcement should be as specified in technical specification

2.9 Check cut off level of piles as per drawing.

2.10 Check recording of all data during installation of piles in prescribed pile data

sheet.

2.11 Check that vibrators are used for preparation of test cubes/ specimens.

2.12 Slumps of concrete shall be tested at every one-hour interval.

2.13 Checking position and Alignment: Each pile shall be checked for its position

w.r.t. specified location. Each pile shall be checked for its alignment. Permissible

limits for deviation shall be as specified elsewhere in the Contractor’s Technical

Specification.

2.14 Check for pile Bore: On completion of boring and cleaning, the bottom of

each pile bore shall be checked from the samples collected from near the bottom

of piles bore or any other method approved by contractor’s Engineer, to ensure

that it is free from pile bore spoil/debris and any other loose material before

concreting.

2.15 Law strain pile integrity test on all job piles and test piles shall be conducted

as specified in the Contractor’s Technical Specification. This test shall be used to

identify the piles for routine tests.

3. Quality Assurance Requirements for RCC Piles (Part-V) Load Test on Piles.

3.1 Pile load testing shall conform to IS: 2911 (Part IV) and Contractor’s Technical

Specification.

3.2 Check all the equipments and instruments used are properly calibrated.

3.3 Initial load test and routine load test shall be carried out.

3.4 Initial load test to assess the safe load carrying capacity of pile before start of

work

3.4.1 Cyclic vertical (Compression) load test to assess safe vertical load capacity

3.4.2 Lateral load test to assess safe horizontal load capacity

3.4.3 Pull out (Tension) load test to assess safe pull out load capacity.

3.4 Routine Load Test on Working Piles.

3.4.1 Direct Vertical (Compression) load test for vertical load capacity.

3.4.2 Lateral load test for horizontal load capacity.

3.5 All other tests on piles shall be carried out as specified in Contractor’s

Technical Specification.

3.6 Pile load testing procedure to be got approved from contractor.

4. SAFETY.

GENERAL SITE SAFETY RULES & REGULATIONS

4.1 Induction: Safety induction is must for one and all at the site

4.2 Every accident and near miss event must be reported to safety officer and or

Time Office.

4.3 Any person found to be interfering with or misusing fixtures, fittings or

equipment provided in the interest of health, safety and welfare will be excluded

from Site.

4.4 Smoking is prohibited at any areas.

4.5 Vehicle Drivers must wear a safety helmet at all times when at risk. Vehicles

are not to be reversed in construction areas unless under the control of an

authorized person.

4.6 Safety signs and notices must be followed.

4.7 Transistor radios or personal stereos / walkman must not be used.

4.8 All Site personnel, for their own safety and for the safety of others, are

required to fully comply with the agreed safety systems / procedure and working

method.

4.9 Site fire and emergency procedures are designed to protect life. They must

be followed.

TECHNICAL SPECIFICATIONFOR

CEMENT CONCRETE(PILING WORKS)

TABLE OF CONTENT

CLAUSE NO. D E S C R I P T I O N

1.0 SCOPE

2.0 GENERAL

2.1 Work to be provide for by the Sub-contractor

2.2 Work by Others

2.3 Information to be submitted by the Sub-contractor

2.4 Conformity with Design

2.5 Materials to be used

2.5.1 General Requirement

2.5.2 Cement

2.5.3 Aggregate

2.5.4 Water

2.5.5 Admixture

2.6 Storage of materials

2.6.1 General

2.6.2 Cement

2.6.3 Aggregates

2.6.4 Reinforcement

2.7 Quality Control

3.0 INSTALLATION

3.1 Washing and screening of Aggregates

3.2 Admixture

3.3 Grades of concrete

CLAUSE NO. D E S C R I P T I O N

3.4 Proportioning and works Control

3.4.1 General

3.4.2 Mix Design Criteria

3.5 Strength Requirements

3.6 Minimun Cement Content

3.7 Water-Cement Ratio

3.7.1 Strength Requirement

3.7.2 Durability Requirement

3.8 Workability

3.9 Size of Coarse Aggregate

3.10 Mixing of Concrete

3.11 Conveying Concrete

3.12 Protection and Curing of Concrete

3.13 Reinforcement

3.13.1 Bar Bending Schedules

3.13.2 Cleaning

3.13.3 Cutting ＆ Bending of Reinforcement

3.13.4 Placing in Position

3.13.5 Welding

3.13.6 Control

3.14 Hot Weather Concreting

3.15 Concreting under water

3.16 Precast concrete

4.0 SAMPLING AND TESTING

4.1 General

4.2 Comment

4.3 Aggregates

4.4 Water

4.5 Admixture

CLAUSE NO. D E S C R I P T I O N

4.5.1 Other Admixtures

4.6 Concrete

5.0 ACCEPTANCE CR1TERIA

5.1 Standard Deviation

5.2 Acceptance Criteria

5.3 Inspection and Core Tests

6.0 LIST OF I.S.:CODES AND STANDARDS FOR REFERENCE

TECHNICAL SPECIFICATION

FOR

CEMENT CONCRETE (PILING WORKS)

1.0 SCOPE

1.1 General

This specification covers all the requirements, described hereinafter for general use of Reinforced Cement Concrete work in Piling works and locations,cast-in-situ or precast, and shall include all incidental items of work not shown or specified but reasonably implied or necessary for the completion of the work. The grade of concrete to be used for piling works shall be M-30 grade with minimum cement content of 400Kg/cum

1.2 This specification shall also apply to the extent it has been referred to or applicable with the special requirements of structures covered in SCOPE of IS:456.

1.3 IS:456 shall form a part of this specification and shall be complied with unless permitted otherwise. For any particular aspect not covered by this Code, appropriate IS Code, specifications and/or replacement by any International Code of practice as may be specified by the Engineer shall be followed. All codes and Standards shall conform to its latest revisions. A list of IS codes and Standards is enclosed hereinafter for reference.

2.0 GENERAL

2.1 Work to be provided for by the Sub-contractor

The work to be provided for by the Sub-contractor, unless otherwise specified shall include but not be limited to the following:

a) Furnish all labour, supervision, services including facilities as may be required under statutory labour regulations, materials, forms, templates, supports, scaffolds, approaches, aids, construction equipment, tools and plants, transportations. etc. required for the work

b) Except where it is excluded from the Scope of Contract. Sub-contractor shall prepare progressively and submit for approval detailed drawings and Bar Bending Schedules for reinforcement bars showing the positions and details of spacers, supports, chairs, hangers etc

c) Submit for approval detailed drawings of supports, templates, hangers. etc. required for installation of various embedments like inserts, anchor bolts, pipe sleeves, frames, joint seals, frames, openings etc.

d) Submit for approval detailed schemes of all operations required for executing the work, e g Material handling. Concrete mixing, Placement of concrete, Compaction. curing, services, Approaches, etc.

e) Design and submit for approval concrete mix designs required to be adopted on the job

f) Furnish samples and submit for approval results of tests of various

properties of the following：

i. The various ingredients of concrete

ii. Concrete

iii. Embedment's

iv. Joint seals

g) Provide all incidental items not shown or specified in particular but reasonably implied or necessary for successful completion of the work in accordance with the drawings. specifications and Schedule of Items.

2.2 Work by others

No work under this specification will be provided by any agency other than the Sub-contractor unless specifically mentioned elsewhere in the contract.

2.3 Information to be submitted by the Sub-contractor

2.3.1 The following technical information are required to be provided by Sub-contractor :

a) Source and arrangement of processing of aggregates proposed to

be adopte.

b) Type of plant and equipment proposed to be used.

c) Names of firms, if any. with which association is sought for to execute the special items of work in the contract

2.3.2 The following information and data including samples where necessary, shall be submitted by the Sub-contractor progressively during the execution of the contract.

a)　Programme of Execution and Requirement of Materials Within 30

days of the award of contract, the Sub-contractor will submit a Master Programme for completion of the work giving month-wise requirements of materials. particularly mentioning in details the materials which are to be supplied by the Contractor and for the procurement of which the help of the Contractor is required as per the terms

and conditions of the Contract, In case the Sub-contractor proposes to take on hire any machineries or tools and plants from the Contractor, the detailed phased out programme of such hire is also to be submitted.

This Master Programme may have to be reviewed and updated by the Subcontractor, quarterly or at more frequent intervals as may be directed by the Engineer depending on the exigencies of the work.

Detailed day to day programme of every month is to be submitted by the Sub-contractor before the end of the previous

month

b) Samples

Samples of the following materials and any other materials proposed to be used, shall be submitted as directed by the Engineer, in sufficient quantities free of cost. for approval. Approved samples will be preserved by the Engineer for future

reference. The approval of the Engineer shall not, in any way, relieve the Sub-contractor of his responsibility of supplying materials of specified qualities:

i. Coarse and fine aggregates

ii. Admixtures

iii. Embedded and anchorage materials as may be desired by the Engineer.

c) Design Mix

Design mix as per Clauses 2.1 (e) & 3.4 of this specification giving proportions of the ingredients, sources of aggregates and cement, along with accompanying test results of trial mixes as per relevant I.S., is to be submitted to the Engineer for his approval before it can be used on the works.

d) Detail Drawings and Bar Bending Schedules

Detailed working drawings and Bar Bending Schedules in accordance with Clause 2.1(b) and 3.16 1 of this specification.

e) Detailed Drawings for Templates & Temporary Supports for Embedment's As per Clause 2 1 (c)

f) Mill Test Reports for Cement & Reinforcing Steel

Mill Test Reports for Cement and Reinforcing Steel in case these materials are supplied by the Sub-contractor.

g) Inspection Reports

Inspection Reports in respect of Reinforcement and any other item of work as may be desired by the Engineer in accordance with Clause 2.4 of this specification

h) Test Reports

Reports of tests of various materials and concrete as required under Clause 4.0 SAMPLING & TESTING of this specification.

i) Any other data which may be required as per this specification.

2.4 Conformity with Design

The Sub-contractor will prepare check lists in approved proforma which will be called

'Pour Cards' These Pour Cards will list out all items of work involved The Sub-contractor will inform the Engineer, sufficiently in advance, whenever any particular pour is ready for concreting. He shall accord all necessary help and assistance to the Engineer for all checking required in the pour On satisfying himsetf that all details are in accordance to the drawings and specifications, the Engineer will give written permission on the same 'Pour Card' allowing the Subcontractor to commence placement of concrete. Details of all instructions issued by the Engineer and the records of compliance by the Sub-contractor. deviations allowed by the Engineer and any other relevant information will be written on accompanying sheets attached to the Pour Cards. These sheets, termed as 'Progress Cards', will be prepared by the Sub-contractor on approved proforma. The Pour Cards along with accompaniments will be handed over to the Engineer before starting placement of concrete. One of the mix designs developed by the Sub-contractor as per the I.S. Specifications and established to the satisfaction of the Engineer by trial mixes shall be permitted to be used by the Engineer, the choice being dictated by the requirements of designs and workability. The methods of mixing, conveyance, placement. vibration, finishing,protection and testing of concrete will be as approved or directed by the Engineer.

2.5 Materials to be used

2.5.1 General Requirement

All materials whether to be incorporated in the work or used temporarily for the construction shall conform to the relevant IS Specifications unless stated otherwise and be of best approved quality.

2.5.2 cement

Generally cement shall be 33 grade ordinary Portland Cement conforming to IS-269. In special cases any of the following type of cement may be permitted or directed to be used with prior approval by the Engineer :

a) 43 Grade ordinary Portland Cement conforming to IS-8112

b) 53 Grade ordinary Portland Cement conforming to IS-12269

c) Rapid hardening Portland Cement conforming to IS-8041

d) Portland slag cement conforming to IS-455

e) Portland Pozzolona Cement ( flyash based ) Conforming to IS- 1489 ( Part -1 )

f) Portland pozzolona Cement ( calcined clay based ) conforming to IS -1489 ( part-2 )

g) Hydrophobic Cement conforming to IS-8043

h) Low heat Portland Cement conforming to IS 12600

i ) Sulphate Resisting Portland Cement conforming to IS-12330

2.5.3 Aggregates

Aggregates shall be natural or crushed gravel or crushed rock and free from deleterious material. It shall comply with the requirements of IS-383 All fine and coarse aggregate shall be tested for susceptibility to Alkali Silicate reaction in a laboratory approved by the Engineer.

a) Coarse Aggregate

Aggregate of sizes ranging between 4 75 mm and 150 mm will be termed as Coarse Aggregate. Only Coarse Aggregate from approved quarries and conforming to IS:383 will be allowed to be used on the works. Aggregates shall be washed to make it free from deleterious materials , if necessary.

The grading of coarse aggregates by sieve analysis shall be as per IS:383 . If by the analysis the deficiency of a particular grain size is found , which could affect the density of the concrete , the Engineer may ask the Sub-contractor to avoid such quantities of aggregate of the particular size or and such quantity of aggregate of any particular size to achieve the required grading as per IS:383.

b) Fine Aggregate

Aggregate smaller than 4 75 mm and within the grading limits and other requirements set in IS:383 is termed as Fine Aggregate or Sand Only Fine Aggregate from approved sources and conforming to the above IS Specification will be allowed to be used on works.

In certain cases there may be two types of sand . one very fine and the other very coarse In such cases , the two types shall be combined to meet the requirements of a particular zone of IS:383. In all cases , the preferred zone is Zone - II.

In certain cases crushed stone sand may be added to natural sand in order to achieve the required grading.

Crushed stone sand alone may be used only with the approval of the Engineer.

2.5.4 Water

Water for use in Concrete shall be dear and free from injurious oils, acids, alkalis, organic matter, salt. silts or other impurities Normally potable water is found to be suitable, Generally. IS:3550 will be followed for routine tests. Acceptance test for water shall be as per IS:3025, and Table-I of IS:456

In case of doubt regarding development of strength, the suitability of water for making concrete shall be ascertained by compressive strength and initial setting time tests as per method of tests in accordance with the requirements of IS -516 & IS- 4031 respectively. The PH value of water shall generally be not less than 6.

2.5.5 Admixture

Only admixture of approved quality will be used when directed or permitted by the Engineer . The different types of admixtures which may be necessary to satisfy the concrete mix and the design requirement shall be as per the following IS. Standards

IS 2645 - Integral cement water proofing compound

IS : 9103 - Indian standard specification for Admixtures for Concrete

or equivalent American Codes (ASTM C494 and ASTM C260 ) or British Codes ( BS 5075 , Part 1 to 3) and may be one of the following :

a) Accelerating admixtures

- Set accelerating admixtures like "Sigunit Powder' or "Sigunit LN10" or approved equivalent.

b) Retarding admixtures :

- Modified ligno sulphonate based set retarding concrete admixture like . "Plastiment R" or approved equivalent.

a) Water reducing admixtures

- Modified sulphonated melamine formaldehyde based water reducing concrete admixture like, "Sikament" or approved equivalent.

c) Air entraining admixtures

- Modified ligno sulphonate based air entraining concrete admixture like "FLOMO AEP " or surface - active agents like "Sika AER" or approved equivalent.

e) Water proofing admixtures

- Modified lingo-sulphonate based waterproofing admixture like "Plastocrete Super" or approved equivalent.

However the Sub-contractor shall furnish following technical information about the admixtures ( along with the manufacturers Catalogue ) which he is planning to use in different areas within the scope of work for the approval of the Engineer

i) Type of admixture

ii) Mix proportion & mode of application in concrete/mortar

ii) Manufacturers specification 8. necessary quality assurance certificates ( mainly on chloride & sulphate content , PH value , infra red analysis & solid content )

2.5.6 Reinforcement

Reinforcement shall be as per relevant IS Specification as mentioned in the Contract/Drawing/Instructions. All bars shall be of tested quality.

2.6.0 Storage of Materials

2.6.1 General

All materials shall be so stored as to prevent deterioration or intrusion of foreign matter and to ensure the preservation of their quality and fitness for the work. Any material, which has deteriorated or has been damaged or is otherwise considered defective by the Engineer, shall not be used for concrete and shall be removed from site immediately, failing which, the Engineer shall be at liberty to get the materials

removed and the cost incurred thereof shall be realised from the Sub-contractors dues. The Sub-contractor shall maintain up-to-date accounts of receipt, issue and balance (stack wise) of all materials Storage of materials shall conform to IS•4082.

2.6.2 Cement

Sufficient space for storage, with open passages between stacks, shall be arranged by the Sub-contractor to the satisfaction of the Engineer.

Cement shall be stored off the ground in dry, leak proof, well-ventilated warehouses at the works in such a manner as to prevent deterioration due to moisture or intrusion of foreign matter.

Cement shall be stored in easily countable stacks with consignment identification marks Consignments shall be used in the order of their receipts at site. Sub -standard or partly set cement shall not be used and shall be removed from the site, with the knowledge of the Engineer, as soon as it is detected.

Different types of cement shall be clearly marked with the type & different types of cement shall not be intermixed.

2.6.3 Aggregates

Aggregates shall be stored on planks or steel plates or on concrete or masonry surface Each size shall be kept separated with wooden or steel or concrete or masonry bulk- heads or in separate stacks and sufficient care shall be taken to prevent the matenal at the edges of the stock piles from getting intermixed Stacks of fine and coarse aggregates shall be kept sufficiently apart with proper arrangement of drainage. The aggregates shall be stored in easily measurable stacks of suitable depths as may be directed by the Engineer

2.6.4 Reinforcement

Reinforcing steel shall be stored consignment-wise and size-wise off the ground and under cover, if desired by the Engineer. It shall be

protected from rusting, oil, grease and distortions. If necessary, the reinforcing steel may be coated with cement wash before stacking to prevent scale and rust at no extra cost to the Contractor. The stacks shall be easily measurable Steel needed for immediate use shall only be removed from storage.

2.7 Quality Control

Sub-contractor shall establish and maintain quality control for different items of work and materials as may be directed by the Engineer to assure compliance with contract requirements and maintain and submit to the Engineer records of the same. The quality control operation shall include but not be limited to the following items of work :

a) Admixture　　 : Type, quantity, physical and chemical properties

that affect strength, workability and durability of concrete

For air entraining admixtures, dosage to be adjusted to maintain air contents within desirable limits

b)Aggregate 　：Physical, chemical and mineralogical qualities. Grading,

moisture content and impurities.

c) Water 　：Impurities tests

d) Cement ：Tests to satisfy relevant IS Specifications (only association with Contractor's tests, if the supply is made by Contractor).

e) Reinforcemen ：Shapes, dimensions, length of splices, clearances,

ties and supports. Quality and requirement of welded splices.

Material tests or certificates to satisfy relevant IS

Specification (If Sub-contractor's supply).　

f) Grades of concrete：Usage and mix design, testing of all properties.

g) Batching & Mixing：Types and capacity of plant, concrete mixers

and transportation equipment.

h) Embedded and ：Material, shape, location, setting

Anchorage Items

i) Placing ：Preparation, rate of pouring, weather limitations,

time intervals between mixing and placing and between two successive lifts. covenng over dry or wet surfaces, cleaning and preparation of surfaces on which concrete is to be placed, application of mortar/slurry for proper bond, prevention of cold joint, types of chutes or conveyors.

　　　　　j) Compaction ：Number of vibrators, their prime mover , frequency

and amplitude of vibration, diameter and weight of vibrators, duration of vibration, hand-spreading. rodding and tamping.

k) Cruing ：Methods and length of time.

Copies of records and tests for the items noted above. as well as, records of corrective action taken shall be submitted to the Engineer f or approval as may be desired

3.0 INSTALLATION

All installation requirements shall be in accordance with IS 456 and as supplemented or modified herein or by other best possible standards where the specific requirements mentioned in this section of the specification do not cover all the aspects to the full satisfaction of the Engineer.

3.1 Washing and Screening of Aggregates

Washing and Screening of coarse aggregate shall be carried out to remove fines , dins or other deleterious materials.

Washing of fine aggregate shall not be allowed, Fine aggregates shall be screened only to remove dirt or other deleterious materials.

However , all washing & screening of aggregates shall be carried out by approved means to ensure compliance with the aggregate specification.

3.2 Admixture

All concrete shall be designed for normal rate of setting and hardening at normal temperature. Variations in temperature and humidity under different climatic conditions will affect the rate of setting and hardening, which will, in turn, affect the workability and quality of the concrete Admixtures may be permitted to be used in accordance with IS: 456 to modify the rate of hardening, to improve workability or as an ad to control concrete quality. The Engineer reserves the right to require laboratory test or use test data, or other satisfactory reference before granting approval. The admixture shall be used strictly in accordance with the manufacturer's directions and/or as directed by the Engineer.

3.3 Grades of Concrete

Concrete shall be in any of the grades designated in IS:456. Grade of concrete to be used in different parts of work shall be as shown on the drawing or as per the Engineer's instructions.

3.4 Proportioning and Works Control

3.4.1 General

Batching Plant only to be used for manufacturing of concrete for piling works. All concrete to be used for piling to be proportioning of ingredients of concrete shall be made by any of the two following methods as directed by the Engineer.

a) With preliminary tests by designing the concrete mix. Such concrete shall be called 'Design Mix Concrete'.

b) Without preliminary tests adopting nominal concrete mix. Such concrete shall be called 'Nominal Mix Concrete'.

Only design mix concrete shall be used on all concrete works. Nominal

mix concrete. in grades permitted in accordance with IS 456, may be used if shown on drawings or approved by the Engineer. In all cases the proportioning of ingredients and works control shall be in accordance with IS 456 and shall be adopted for use after the Engineer is satisfied regarding its adequacy and after obtaining his approval in writing.

3.4.2 Mix Design Criteria

Concrete mixes will be designed by the Sub-contractor to achieve the strength, durability and workability necessary for the job, by the most economical use of the various ingredients. In general, the design will keep in view the following considerations:

a) Consistent with the various other requirements of the mix, the quantity of water should be kept at the lowest possible level.

b) The nominal maximum size of coarse aggregate shall be as large as possible within the limits specified

c) The various fractions of coarse and fine aggregates should be mixed in such a proportion as to produce the best possible combined internal grading giving the densest and most workable mix.

d) Chemical admixtures may be used to modify the rate of hardening, to improve workability (maintaining low water - cement ratio ) or as an aid to control concrete quality.

e) The finished concrete should have adequate durability in all conditions, to withstand satisfactorily the weather and other destructive agencies which it is expected to be subjected to in actual service.

The requirement of adequate structural strength is catered for by the choice of proper grade of concrete by the Engineer. The Sub-contractor will strictly abide by the same in his design of concrete mix installation

Notwithstanding anything mentioned in various tables given in IS' 456 giving specific values and degrees of workability for different condition of concrete placing, minimum cement content and maximum water-cement ratio for concrete exposed to sulphate attack and for concrete to ensure durability under different condition of exposure. strength

requirement for different grades of concrete, proportion for nominal mix concrete, the following tables in the specification are included. For identical condition if values given in the tables shown herein below are different from those mentioned in IS: 456, the values as indicated in the table shown herein below shall prevail.

Vanous trials shall be given by the Sub-contractor with specific cement content on each trial In some cases, plasticizers and other admixtures may be necessary to achieve the desired results.

TABLE—I

STRENGTH REQUIREMENT OF CONCRETE

　　　　　　　　　　　　　　

　　　　　　　　　　　　　Specified Characteristic Compressive

Grade of concrete strength of 15 cm

Cubes at 28 days conducted in accordance

with IS:516

(All values in NiSq.mm)

M-25 25

M-30 30

M-35 35

M-40 40

TABLE--II

MIX PROPORTIONS (BY WEIGHT) EXPECTED TO GIVE

DIFFERENT DEGREES OF WORKABILITY WITH DIFFERENT

VALUES OF WATER - CEMENT RATIO

(FOR GUIDANCE) CEMENT/TOTAL

AGGREGATE RATIOS

WORKABILITY

WATER/

CEMENT

RATIO

RATIO BY WEIGHT OF

CEMENT TO GRAVEL

AGGREGATE

RATIO BY WEIGHT OF CEMENT

TO CRUSHED STONE

AGGREGATE

20 mm

size

38 mm

size

20 mm

size

38 mm

size

Very tow

Slump

0-25 mm

0.4

0.5

0 6

0.7

1:4.8

1:7.2

1:9.4

1:10

1:5.3

1:7.7

1:10

1:12

1:4.5

1:6.5

1:7.8

1:8.7

1:5.0

1:7.4

1:9.6

1:10.6

Low

Slump

25-50 mm

0,4

0.5

0.6

0.7

1:3.9

1:5.5

1:6.8

1:8.0

1:4.5

1:6.7

1:7.4

1:8.5

1:3.5

1:5.0

1:6.3

1:7.4

1:4,0

1:5.5

1:7.0

1:8.0

Medium

Slump

50-100 mm

0.4

0.5

0,6

1:3.5

1:4.8

1:6.0

1:3.8

1:5.7

1:7.3

1:3.1

1:4.2

1:5.2

1:3.6

1:5.0

1:6.2

High

Slump

100-175 mm

0.4

0.5

0.6

0.7

1 3 2

1:4.4

1:5.4

1:6.2

1:3.5

1:5.2

1:6.7

1:7.4

1:2.9

1:3.9

1:4.7

1.5.5

1:3.3

1:4.6

1:5 7

1:6.5

NOTE:１- Notwithstanding anything mentioned above, the cement/Total aggregate

ratio is not be increased beyond 1.9.0 without specific permission of the Engineer

NOTE: １ -It should be noted that such high aggregate cement ratios will be

required for concretes of very low slump and high water-cement ratios which may be required to be used in mass concrete work only.

NOTE:３- The above figures are for guidance only, the actual cement/ aggregate

ratios are to be worked out from the specific gravities of coarse aggregates and sand being used and from trial mixes.

3.5 Strength Requirements

The strength requirements of both design mix and nominal mix concrete where ordinary Portland Cement or Portland slag cement is used, shall he as per Table -2 of IS.456. All other relevant clauses of IS:456 shall also apply.

3.6 Minimum Cement Content

The minimum cement content for each grade of concrete shall be as shown below.

TABLE-III

MINIMUM CEMENT CONTENT SPECIFIED

FOR DIFFERENT GRADES OF CONCRETE

Grade of Concrete　　　　　 Minimum Cement Content/Cu.M

of Finished Concrete

Ｍ-30 400Kg

M-35 490Kg

M-40 540Kg

The minimum cement contents mentioned above are for average conditions and for 20 mm size aggregate. For 40 mm size aggregate the cement content may be reduced. In case the cement content can be reduced due to continuous and consistent favourable conditions, on

account of better quality of cement control or by the addition of suitable plasticizer / super plasticizers, then the Engineer may instruct lower cement content, and the Sub-contractor shall abide by the stipulations laid down hereunder:

a) The Sub-contractor shall design the mixes for 10% (Ten per cent) higher strength over and above those specified in Table-I under Clause 3.4, for the various grades of concrete and different slump requirements.

b) Sufficient number of trial mixes (to be decided by the Engineer) will be taken at the laboratory for the various designs and graphs of w/c ratio Vs crushing strengths at various ages will be plotted.

c) All tests will be done in presence of the Engineer who shall be the final authority to decide upon the adoption of any revised minimum cement content. The Subcontractor will always be responsible to produce quality concrete of the required grade as per the acceptance criteria of IS-456.

d) The Engineer will always have the unquestionable right to revise the minimum cement content as decided above, if, in his opinion, there is any chance of deterioration of quality on account of use of lower cement content or any other reason.

In case there is a downward revision of the minimum cement content from that specified in the contract, the particular unit rate of concrete will be reduced by an amount equal to the cost of cement saved, calculated at the issue rate The relevant cost of wastage and handling on the cement saved, which is inherent in the total cost of structure, will not be deducted from the unit rate and will thus pass on to the Sub-contractor

3.7 Water-Cement Ratio

The choice of water-cement ratio in designing a concrete mix will depend on -

b) The requirement of strength.

c) The requirement of durability.

3.7.1 Durability Requirement

Tables 19 & 20 of IS:456 give the maximum water-cement ratio permissible from the point of view of durability of concrete subjected to adverse exposure to weather, sulphate attacks, and

contact with harmful chemicals. Impermeability may also be an important consideration

Whenever the water-cement ratio dictated by durability consideration is lower than that required from strength criterion, the former shall be adopted.

However. water-cement ratio, from the point of view of durability as well as from strength consideration, should meet the requirement given in Table No IV.

In general the water cement ratio shall be 0.5 for piling works to satisfy the durability requirement and slump shall be 100 – 150mm. The Sub-contractor may propose lower water cement ratio as mentioned above by addition of a suitable plasticizer / super- plasticizer . However the Sub-contractor has to propose specifically along with field trials in the event of lower cement content if found suitable along with a plasticizer . It will be preferable to use Melamine based plasticizer.

TABLE-V　(NOT APPLICABLE FOR PILING WORKS)

MAXIMUM PERMISSIBLE WATER/CEMENT RATIOSFROM DURABILITY CONSIDERATIONS FOR DIFFERENT

TYPES OF STRUCTURES AND DEGREES OF

EXPOSURE USING ORDINARY PORTLAND CEMENT

Exposure Conditions

Type of Structure Severe wide rage of

temperature

Frequent alteration of freezing

and thawing (use Air Entrained

concrete only)

Mild Temperature rarely below

freezing or rainy or arid

At the water tine or

within the range of

fluctuating water level

or spray.

At the water line or

within the range of

fluctuating water level

or spray.

In

Air

In

fresh

water

In sea water or

in contact with

sulphate

(concentration

more than 0.2

P.C)

In

Air

In

fresh

water

In sea water or

in contact with

sulphate

(concentration

more than 0.2

P.C)

Thin sections such as

railings kerbs, sills

ledges, ornamental or

Architectural concrete

reinforced concrete piles,

pipes and all sections

with less than 25 mm

concrete cover to

reinforcement.

0.4

9 0.44 0.40

0.5

3 0.49 0.40

Moderate sections such

as Retaining Walls.

abutements, piers,

girders, beams

0.5

3 0.49 0.40 * 0.53 0.44

Exterior portions of heavy

mass sections.0.5

8 0.49 0.44 * 0.53 0.44

Concrete deposited by

Tremie under water - 0.44 0.44 - 0.44 0.44

Concrete slabs laid on

ground0.5

3

.- - * .- -

Concrete which will later

be protected by

enclosure or backfill but

which may be exposed to

freezing & thawing for

several years before such

protection is offered.

0.5

3 - - * - -

Concrete protected from

the water, interiors of

buildings, concrete below

ground which is free from

sulphate attacks * *

NOTE:　　 * Water/Cement ratios should be selected on basis of strength and

workability requirements.

3.8 WorkabilityThe degree of workability necessary to allow the concrete to be well consolidated and to be worked into the corners of formwork and around the reinforcement and embedment and to give the required surface finish shall depend on the type and nature of structure and

shall be based on experience and tests. The usual limits of consistency for various types of structures are given below.

TABLE-V LIMITS OF

CONSISTENCY

Degree of

Workability

Slump in mm with Standard

Code as per IS : 1199 Use for which concrete is suitable

Min. Max.

Very low 0 25 Large Mass concrete structure with

heavy compaction equipments, roads

and like

low 25 50 Uncontested wide and shallow R.C.C.

structures

Medium 50 100 Deep but wide R.C.C. structures with

congestion or reinforcement ands

inserts

Hihg 100 150 Piling works & very narrow and deep-

R.0 C structures with congestion due

to reinforcement and inserts.

NOTE： Notwithstanding anything mentioned above, the slump to be obtained for

work inprogress shall be as per direction of the Engineer)

With the permission of the Engineer, for any grade of concrete, if the water has to be increased in special cases. cement shall also be increased proportionately to keep the ratio of water to cement same as adopted in trial mix design for each grade of concrete. No extra payment will be made for this additional cement. The workability of concrete shall be checked at frequent intervals by slump tests. Alternatively where facilities exist or if required by the Engineer, the compacting factor test in accordance with IS :1199 and Clause 6 of IS 456 shall be carried out.

3.9 Size of Coarse Aggregates

The maximum size of coarse aggregates for different locations shall

be as followsunless otherwise directed by the Engineer :-

Very narrow space - 12 mm

Reinforced concrete except foundation - 20 mm

Grading of coarse aggregates for a particular size shall conform to relevant I.S. Codes and shall also be such as to produce a dense concrete of the specified proportions, strength and consistency that will work readily into position without segregation.

Coarse aggregate will normally be separated into the following sizes and stackedseparately in properly designed stockpiles :

150 mm to 80 mm, 80 mm to 40 mm, 40 mm to 20 mm and 20 mm to 5 mm. In certain cases it may be necessary to further split the 20 mm to 5 mm fraction into 20 mm to 10 mm and 10 mm to 5 mm fractions.

This separation of aggregates in different size fractions is necessary so that they may be remixed in the desired proportion to arrive at a correct internal grading to produce the best mix.

3.10 Mixing of Concrete

Batching plant only to be employed for manufacturing of concrete. For unimportant works apart from piling works, conventional mechanical mixer can be used with prior permission of the site in charge Water shall not normally be charged into the drum of the mixer until all the cement and aggregates constituting the batch are already in the drum and mixed for at least one minute. Mixing of each batch shall be continued until there is a uniform distribution of the materials and the mass is uniform in colour and consistency, but in no case shall mixing be done for less than 2 (two) minutes and at least 40 (forty) revolutions after all the materials and water are in the drum. When absorbent aggregates are used or when the mix is very dry, the mixing time shall be extended as may be directed by the Engineer.

Mixers shall not be loaded above their rated capacity as this prevents thorough mixing.

The entire contents of the drum shall be discharged before the ingredients for the next batch are fed into the drum. No partly set or remixed or excessively wet concrete shall be used. Such concrete shall be immediately removed from site. Each time the work stops, the mixer shall be thoroughly cleaned & when the next mixing commences.

the first batch shall have 10% additional cement at no extra cost to the Contractor to allow for loss in the drum.

Regular checks on mixer efficiency shall be carried out as directed by the Engineer as per IS :4634 on all mixers employed at site, Only those mixers whose efficiencies are within the tolerances specified in IS :1791 will be allowed to be employed.

Ingredients for design mix concrete shall be measured by weight. For small jobs portable swing weigh Batchers conforming to IS 2722 may be used.

For piling works concrete mixing to be done only on Batching plant having facilities of electronic print out conforming to IS: 4925. Batching Plant shall be calibrated on every 3 months intervals and calibration certificate to be submitted to the Site in charge. The accuracy of the measuring equipment shall be within + 2% of the quantity of Cement, water or total aggregates being measured and within + 5% of the quantity of any admixture being used The batching equipment shall be fitted with an accurate mechanism for weighing separately the cement, fine aggregate and coarse aggregate. Water may be measured by volume or by weight. All measuring equipment should be maintained in a clean serviceable condition, and their accuracy shall be checked periodically.

Mechanical I electrical control shall be provided on the mixing equipment to ensure the batch cannot be discharged until approved mixing time has elapsed and the entire batch shall be discharged before the mixer is recharged.

Where admixtures are employed, separate containers & measuring devices shall be used.

For minor concreting works. batching by volume according to specific weight may be permitted by the Engineer. In that case the whole bags of cement shall be used and gauge boxes used for measuring aggregates.

When hand mixing is permitted by the Engineer, it shall be carried out on a watertight platform and care shall be taken to ensure that mixing is continued until the mass is uniform in colour and consistency. In case of hand-mixing. 10% extra cement shall be added to each batch at no extra cost to the Contractor.

3.11 Conveying Concrete

Concrete shall be handled and conveyed from the place of mixing to the place of laying as rapidly as practicable by approved means and placed and compacted in the final position before the initial setting of the cement starts. Concrete should be conveyed in such a way as will prevent segregation or loss of any of the ingredients. For long distance haulage, agitator cars of approved design will be used If, inspite of all precautions. segregation does occur during transport, the concrete shall be properly re-mixed before placement. During very hot or cold weather, if directedby the Engineer, concrete shall be transported in deep containers, which will reduce the rate of loss of water, by evaporation or loss of heat. If necessary, the container may have to be covered and insulated. Conveying equipments for concrete shall be well maintained and thoroughly cleaned before commencement of concrete mixing. Such equipments shall be kept free from set concrete.

3.12 Protection and Curing of concrete

Newly placed concrete shall be protected by approved means from rain, sun and wind. Concrete placed below the ground level shall be protected against contamination from falling earth during and after placing Concrete placed in ground containing deleterious substances, shall be protected from contact with such ground. or with water draining from such ground, during placing of concrete and for a period of at least three days or as otherwise instructed by the Engineer. The ground water around newly poured concrete shall be kept to an approved level by pumping out or other adequate means of drainage to prevent floatation or flooding. Steps, as approved by the Engineer, shall be taken to protect immature concrete from damage by debris, excessive loadings, vibration, abrasion, mixing with earth or other deleterious materials. etc. that may impair the strength and durability of the concrete.

As soon as the concrete has hardened sufficiently, it shall be covered either with sand. polythene sheet, hessian, canvas or similar materials and kept continuously wet for at least 14 (fourteen) days after final setting. Cunng by continuous sprinkling of water will be allowed if the Engineer is satisfied with the adequacy of the arrangements made by the Sub-contractor.

If permitted by the Engineer, curing compound like "ANTISOLE (WP)" or approved equivalent may be used for prevention of premature water loss in concrete and thereby effecting curing of concrete This type of curing compound shall be sprayed on newly laid concrete surfaces to form thin film barrier against premature water loss without disturbances to normal setting action. The curing compound shall comply with ASTM requirements for acceptance.

The curing compound shall be applied following the final finishing operation and immediately after disappearance of water sheen from concrete surface. It is important not to apply the curing compound when standing water is still present on concrete.

The Sub-contractor shall remain extremely vigilant and employ proper equipment and workmen under able supervision for curing. The Engineer's decision regarding the adequacy of curing is final. In case any lapse on the part of the Subcontractor is noticed by the Engineer, he will inform the Sub-contractor or his supervisor verbally or in writing to correct the deficiency in curing. If no satisfactory action is taken by the Sub-contractor within 3 (three) hours of issuance of such instruction, the Engineer will be at liberty either to employ sufficient means through any agency to make good the deficiency and recover the cost thereof from the Sub-contractor. or pay for the part where adequate curing was noticed at a reduced rate, entirely at the discretion of the Engineer.

3.13 Reinforcement

Mild steel round bars, cold twisted and deformed bars as medium tensile or high yield strength steel (Fe -415, Fe -500 grade), plain hard drawn steel wire fabric etc , will be used as reinforcement as per drawings and directions. In an aggressive environment an anti-corrosive coating on the reinforcement may be provided as per IS 9077 , as shown on the drawing or as directed by the Engineer.

3.13.1 Bar Bending Schedules

The Sub-contractor shall submit to the Engineer for approval Bar Bending Schedules with working drawings in triplicate, showing clearly the arrangements proposed by the Sub-contractor to match available stock of reinforcing steel, within one month of receipt of the Letter of

Intent or of the receipt of the relevant design drawings, whichever is later Upon receipt of the Engineer's final approval of the Bar Bending Schedule and drawings. the Sub-contractor shall submit 6 (six) prints of the final drawings with one reproducible print after incorporating necessary modifications or corrections, for final record and distribution. Approval of such detailed drawings by the Engineer shall not relieve the Sub-contractor of his responsibility for correctness nor of any of his obligations to meet the other requirements of the Contract.

3.13.2 Cleaning

All steel for reinforcement shall be free from loose scales. oil grease, paint or other harmful matters immediately before placing the concrete.

3.13.3 Cutting & Bending of Reinforcement

Unless otherwise specified, reinforcing steel shall be bent in accordance wit h the procedure specified in IS 2502 or as approved by the Engineer Bends and shapes shall comply strictly with the dimensions corresponding to the approved Bar Bending Schedules Bar Bending Schedules shall be rechecked by the Sub¬contractor before any bending is done.

No reinforcement shall be bent when already in position in the work, without approval of the Engineer, whether or not it is partially embedded in concrete. Bars shall not be straightened in a manner that will injure the material. Rebinding can be done only if approved by the Engineer. Reinforcing bars above 16 mm diameter shall be bent by machine producing a gradual and even motion Bars of t6 mm or below may be bent by hand. All the bars shall be cold bent unless otherwise approved. Bending hot at a cherry-red heat (not exceeding 845 Deg C) may be allowed under very exceptional circumstances except for bars whose strength depends on cold working. Bars bent hot shall not be cooled by quenching.

Reinforcing bars, whether high yield or mild steel shall be cut using either hand held shears. guillotines or foot operated pneumatic cutters. Cutting bars using cold chisels may be allowed by the Engineer at exceptional cases.

3.13.4 Placing in Position

All reinforcements shall be accurately fixed and maintained in position as shown on the drawings by such approved and adequate means like mild steel chairs and/or concrete spacer blocks irrespective of whether such supports are payable or not. Bars intended to be in contact at crossing points. shall be securely tied together at all such points by No 20 G annealed soft iron wire Tack welding of bars should not be done unless permitted by the Engineer. Binders shall tightly embrace the bars with which they are intended to be in contact and shall be securely held. The vertical distance between successive layers of bars shall be maintained by provision of mild steel spacer bars They should be spaced such that the main bars do not sag perceptibly between adjacent spacers. Before actual placing, the Subcontractor shall study the drawings thoroughly and inform the Engineer in case he feels that placement of certain bars is not possible due to congestion In such cases he should not start placing any bar before obtaining clearance from the Engineer.

3.13.5 Welding

Normal bond laps in reinforcement may be placed by lap or butt-welding reinforcement bars, if asked by the Engineer, under certain conditions. The work should be done with suitable safeguards in accordance with relevant Indian Standards for welding of mild steel bars used in reinforced concrete construction as per IS 2751 and IS:456. Welded mesh fabrics conforming to IS:1566 may also be used if specified in the Schedule of Items and Drawings.

3.13.6 Control

The placing of reinforcements shall be completed well in advance of concrete pouring. Immediately before pouring. the reinforcement shall be examined by the Engineer for accuracy of placement and cleanliness Necessary corrections as directed by him shall be carried out. Laps and anchorage lengths of reinforcing bars shall be in accordance with IS: 456. unless otherwise specified If the bars in a lap are not of the same diameter, the smaller will guide the lap length The laps shall be staggered as far as practicable and as directed by the Engineer. Arrangements for placing concrete shall be such that

reinforcement in position do not have to bear extra load and get disturbed

The cover for concrete over the reinforcements shall be as shown on the approved drawings unless otherwise directed by the Engineer. Where concrete blocks are used for ensuring the cover and positioning reinforcement, they shall be made of mortar not leaner than 1 (one) part cement to 2 (two) parts sand by volume and cured in a pond for at least 14 (fourteen) days. The type, shape. size and location of the concrete blocks shall be as approved by the Engineer.

3.14 Hot Weather Concreting

When depositing concrete in very hot weather, the Sub-contractor shall take all precautions as per IS 7861 ( Part-I) and stagger the work to the cooler parts of the day to ensure that the temperature of wet concrete used in massive structures does not exceed 40 Deg C while placing. Positive temperature control by precooling, post cooling or any other method, if required, will be specified.

3.15 Concreting under water

When it is necessary to deposit concrete under water it shall be done in accordance with the requirements of clause 13 of IS:456.

3.16 Precast Concrete

The Specification for precast concrete will be similar as for the cast-in-place concrete described herein and as supplemented in this section. All precast work shall be carried out in a yard made for the purpose. This yard shall be dry, properly levelled and having a hard and even as well as well drained surface to prevent excessive uneven settlement due to softening of soil during casting & curing. If the ground is to be used as a soffit former of the units. it shall be paved with concrete or masonry and provided with a layer of plaster (1 2 proportion) with smooth neat cement finish or a layer of M.S sheeting Where directed by the Engineer. casting will have to be done on suitable vibrating table The yard, lifting equipment, curing tank, finished material storage space etc. shall be designed such that the units are not lifted from the

mould before 10 (Ten) days of curing and can be removed for erection after 28 (twenty-eight) days of curing. The moulds shall preferably be of steel or of timber lined with G.I.sheet metal and must be rigid enough to prevent distortion during placing and compaction of the concrete.

Other than normal curing by applying water through spray nozzles or perforated hose curing by high pressure steam • steam vapour or other accepted processes may also be employed to accelerate the hardening of the concrete and to reduce the curing time.

Lifting hooks, where necessary or as directed by the Engineer, shall be embedded in correct position of the units to facilitate erection, even though they may not be shown on the drawings, and shall be burnt off and finished after erection.

All members shall be indelibly marked with a unique identification mark on a surface which will not be permanently exposed to show on which product ion tine they were manufactured, their type the class of concrete, the data of casting and if they are of a symmetrical section the face which will be uppermost when the member is in its correct position after erection.

Precast concrete units, when ready, shall be transported to site by suitable means approved by the Engineer. Care shall be taken to ensure that no damage occurs during transportation. All adjustments, levelling and plumbing shall be done as per instructions of the Engineer. The Sub-contractor shall render all help with instruments, materials and men to the Engineer for checking the proper erection of the precast units.

After erection and alignment, the joints shall be filled with grout or concrete as directed by the Engineer. If centerings have to be used for supporting the precast units, they shall not be removed until the joints have attained sufficient strength and in no case before 14 (fourteen) days, The joint between precast roof planks shall be pointed with 1:2 cement: sand mortar where called for in the drawings.

4.0 SAMPLING AND TESTING

4.1 General

The Sub-contractor shall carry out all sampling and testing in accordance with the relevant Indian Standards and as supplemented herein for the following items at his own cost unless otherwise specified in this specification, The Sub-contractor shall get the specimens tested in a laboratory approved by the Engineer and submit to the Engineer the test results in triplicate within 3 (three) days after completion of the test.

4.2 Cement

Representative samples will be taken from each consignment of cement received from the manufacturer/supplier for carrying out the tests for fineness (by hand sieving), setting time and compressive strengths. Soundness Tests may also be required to be carried out if required by the Engineer. The tests shall be carried out free of charge by the Contractor if cement is supplied by him. In case the Sub-contractor is directed to arrange for the supply of cement as per the terms and conditions of the Contract the tests shall be carried out by him without any expense to the Contractor. In case due to any circumstances, the agency of supply is changed in the middle of the Contract, the party who bore the original contractual obligation will carry on with the test, free of charge to the other, till the end of the job. No cement from a particular consignment/batch will be used on the works unless satisfactory 3 (three) days and 7 (seven) days test results for compressive strength are known. The Contractor, Engineer and Sub-contractor will jointly associate themselves with the tests irrespective of whether they are carried out by the Contractor or the Sub-contractor These tests are of great importance as their results will have a bearing on the acceptance of concrete or otherwise as per the terms and conditions of the Contract.

4.3 Aggregate

The Sub-contractor shall carry out any or all the tests aggregates as may be required by the Engineer in accordance with IS.2386 PARTS-I to VIII. The acceptance criteria of the samples tested shall be in accordance with the requirements of the relevant Indian Standards.

4.4 Water

Sampling and Testing of water being used for concrete works as per IS: 3550 will be carried out by the Sub-contractor at regular intervals and whenever directed by the Engineer. The final acceptance criteria in case of doubt will be as per IS: 3025 & I5:456.

4.5 Admixture

4.5.1 Other Admixture

Tests for establishing the various properties of any other admixtures which may be required to be added shall be carried out by the Sub-contractor free of charge to the Contractor.

4.6 Concrete

The sampling of concrete. making the test specimens, curing and testing procedure etc. shall be in accordance with IS: 516 and IS: 1199 the size of specimen being 15 cm cubes Normally. only compression tests shall be performed but under special circumstances the Engineer may require other tests to be performed in accordance with IS: 516.

Sampling procedure. frequency of sampling and test specimen shall conform to Clause 14 of IS: 456.

To control the consistency of concrete from every mixing plant, slump tests and/or compacting factor tests in accordance with IS: 1199 and as mentioned in Clause 3.6 of this Specification shall be Gamed out by the Sub-contractor every two hours or as directed by the Engineer. Slumps corresponding to the test specimens shall be recorded for reference.

The acceptance criteria of concrete shall be in accordance with Clause 15 of IS 456.

Concrete work found unsuitable for acceptance shall have to be dismantled and replacement is to be done as per specification by the Sub-contractor. No payment for the dismantled concrete. the relevant formwork and reinforcement, embedded fixtures, etc. wasted in the dismantled portion shall be made. In the course of dismantling, if any damage is done to the embedded items or adjacent structures, the same shall be made good, free of charge by the Subcontractor, to the satisfaction of the Engineer.

5.0 ACCEPTANCE CRITERIA

5.1 Standard Deviation

Standard deviation shall be based on test results and determination of Standard deviation shall conform to clause 14.5 of IS: 456.

5.2 Acceptance Criteria

The strength requirements and acceptance criteria shall conform to Clause 15 of IS:456.

5.3 Inspection and Core Tests

Inspection of concrete work immediately after stripping the formwork and core test of structures shall conform to Clause 16 of IS:456.

6.0 LIST OF IS : CODES AND STANDARDS FOR REFERENCE

All work under this specification shall, unless specified otherwise, conform to the latest revisions and/or replacements of the following or any other Indian Standard Specifications and Codes of Practice In case any particular aspect of work is not specifically covered by Indian Standard specifications, any other standard practice, as may be specified by the Engineer. shall be followed:

IS : 73 - Indian Standard Specification for Paving Bitumen IS : 216 - Indian Standard Specification for Coal Tar Pitch

IS 269 - Indian Standard Specification for 33 grade Ordinary Portland Cement

IS 383 - Indian Standard Specification for Coarse and Fine Aggregates from Natural Sources for Concrete

IS . 432 - Indian Standard Specification for Mild Steel and Medium Tensile Steel Bars and Hard Drawn Steel Wire for concrete Reinforcement - Part 1 & 2

IS : 455 - Indian Standard Specification for Portland Slag Cement

IS : 456 - Indian Standard Code of Practice for Plain and Reinforced Concrete

IS : 457 - Indian Standard Code of Practice for General Construction of Plain and Reinforced Concrete for Dams and other Massive Structures

IS 516 - Indian Standard Specification for Methods of Test for Strength of Concrete

IS : 737 Indian standard specification for wrought Aluminium and Aluminium Alloy sheet and strip for general Engineering purpose

IS 1199 - Indian Standard Specification for Methods of Sampling and Analysis of Concrete

IS 1200 - Indian Standard Specification for Method of ( Part-II) Measurement Cement Concrete Works

IS : 1200 - Indian Standard Specification for Method of (Part-V) Measurement of Formwork

IS 1322 - Indian Standard Specification for Bitumen Felts for Waterproofing and Damp-proofing

1S 1489 - Indian Standard Specification for Portland - Pozzolona Cement - Part 1 & 2

IS 1566 - Indian Standard Specification for hard drawn steel wire fabric for concrete reinforcement

IS : 1609 - Code of Practice for Laying Damp-proof Treatment using Bitumen Felts

IS : 1786 - Indian Standard Specification for high strength deformed Bars & wires for Concrete Reinforcement

IS : 1791 - Indian Standard Specification for Batch Type Concrete Mixers

IS : 1834 - Indian standard specification for hot applied sealing compound for joint in concrete

IS : 2062 - Steel for general structural purpose.

IS : 2185 - Indian Standard Specification for Hollow and solid / solid light wt. Cement Concrete Blocks - Part - 1 & 2

IS 2210 - Indian Standard Specification for Design of Reinforced Concrete Shell Structures and Folded Plates

IS : 2386 - Indian Standard Specification for Methods of Test for Aggregates for Concrete - Part-I to VIII

IS 2430 - Indian standard specification for method of sampling of Aggregate for concrete.

IS : 2502 - Indian Standard Code of Practice for Bending and Fixing of Bars for Concrete Reinforcement

IS : 2505 - Indian Standard Specification for Concrete Vibrators Immersion Type IS : 2506 - Indian Standard Specification for Screed Board Concrete Vibrators IS : 2514 - Indian Standard Specification for Concrete Vibrating Tables IS - 2645 - Integral Cement water proofing compound

IS : 2722 - Indian Standard Specification for Portable Swing Weigh Batc hers for Concrete (Single and Double Bucket type)

IS 2751 - Code of Practice for Welding of Mild Steel Bars used for Reinforced Concrete Construction

IS : 2770 - Indian Standard Specification for Method of Testing Bond in Reinforced Concrete Part - 1 : Pull out Test

IS ; 3025 - Indian Standard Specification for Methods of Sampling and Test (Physical and Chemical) for Water & waste water - part - 1 to 37

IS : 3201 - Indian Standard Specification for Design and Construction of Precast Concrete Trusses and purlins

IS : 3370 - Indian Standard Specification for Code of Practice for Concrete Structures for Storage of Liquids Part 1 to 4

IS : 3384 - Indian standard specification for / Bitumen primer for use in waterproofing and Danp proofing

IS : 3414 - Code of practice for Design and Installation of joints in Buildings

IS : 3550 - Indian Standard Specification for Method of Test for Routine Control for Water used in Industry

IS : 3556 - Code of Practice for use of Immersion Vibrators for Consolidating Concrete

IS : 3696 - Safety Code for Part-1 : Scaffolding and Part 2: Ladders

IS : 3812 - Indian Standard Specification for Fly Ash for Use as Pozzolone Admixture

IS : 4031 - Indian Standard Specification for Method of Tests for Hydraulic Cement - Part -1 to 14

IS : 4082 - Indian Standard Specification for Recommendation on Stacking and Storage of Construction Materials at site

IS : 4090 - Indian Standard Specification for Design of Reinforced Concrete Archs

IS : 4634 - Indian Standard Specification for Method of Testing Performance of Batch-type Concrete Mixers

IS : 4656 - Indian Standard Specification for Form Vibrators for Concrete

IS : 4925 - Indian Standard Specification for Concrete Batching and Mixing Plant IS : 4926 - Indian Standard Specification for Ready Mixed Concrete

IS 4990 - Indian Standard Specification for Plywood for Concrete Shuttering work

IS 4991 - Indian Standard Specification for Blast Resistant Design of Structure for Explosion above ground

IS : 4995 - Indian Standard Specification for Design (Part-1&11) of Reinforced Concrete Bins for the Storage of Granular and Powdery Materials

IS : 4998 - Indian Standard Specification for Design of (Part - I) Reinforced Concrete Chimneys

IS 1 5512 - Indian Standard Specification for Flow Table for use in Tests of Hydraulic Cement and Pozzolanic Materials

IS : 5513 - Indian Standard Specification for Vicat Apparatus

IS : 5515 - Indian Standard Specification for Compaction Factor Apparatus

IS : 5751 - Indian Standard Specification for Precast Concrete Coping Blocks

IS 5816 - Indian Standard Specification for Method of Test for Splitting Tensile Strength of Concrete Cylinders

IS 5891 - Indian Standard Specification for Hand Operated Concrete Mixers

IS : 6452 - Indian Standard Specification for High Alumina Cement for Structural Use

IS : 6909 - Indian Standard Specification for Supersulphated Cement

IS 6923 - Indian Standard Specification for Method of Test for performance of Screed Board Concrete Vibrators

IS 6925 - Indian Standard Specification for Method of Test for Determination of Water Soluble Chloride in Concrete Admixtures

IS : 7242 - Indian Standard Specification for Concrete Spreaders

IS 7246 - Indian Standard Specification for Table Vibrators for

Consolidating Concrete

IS : 7251 - Indian Standard Specification for Concrete Finishers

IS : 7320 - Indian Standard Specification for Concrete Slump Test Apparatus

IS : 7861 - Indian Standard Specification for (Part-1&I1) Recommended Practice for hot and cold Weather Concreting

IS 7969 - Safety Code for Storage and Handling of Building Materials

IS : 8041 - Indian Standard Specification for Rapid Hardening Portland cement IS : 8043 - Indian standard specification for hydrophobic cement

IS : 8112 - Indian Standard Specification for 33 grade Ordinary Portland Cement

IS : B142 - Indian Standard Specification for Determining Setting time ofConcrete by Penetration Resistance

IS : 8989 - Safety Code for Erection of Concrete Framed Structures

IS : 9013 - Indian Standard Specification for Method of Making. Curing and Determining Compressive Strength of Accelerated - cured Concrete Test Specimens

IS : 9077 - Code of Practice for Corrosion Protection of Steel Rails in RB and RCC Construction

IS : 9103 - Indian Standard Specification For Admixtures For Concrete

IS : 9417 - Recommendation for welding cold worked bars for

reinforced concrete construction

IS : 10262 - Recommended Guideline For Concrete Mix Design

IS : 12269 – Indian standard specification for 53 grade ordinary Portland cement

IS : 12330 – Indian standard specification for sulplate resting portland cement

IS : 12330 - Indian standard specification for low heat portland cement