SHAHPURKANDI DAM PROJECT

SHAHPURKANDI DAM

PROJECT

BID DOCUMENT FOR

CONSTRUCTION OF AQUEDUCT OVER SUKHRAL KHAD AND ADJOINING NALLAH INCLUDING CONSRUCTION OF BARREL,FLAIR-IN-& FLAIR-OUT-WALLS & PROTECTION WORK FROM RD ± 265.8M TO ± 819.0M OF PROPOSED RAVI CANAL ON EPC MODE

VOLUME-II

WATER RESOURCES DEPARTMENT

GOVERNMENT OF PUNJAB

SUMMARY SHEET OF

BID DOCUMENTS

Volume Section Description Page No.

No. No.

II 10 Technical Specifications 1-117

General Arrangement Drawings and Site 118-122

II 11 Investigation Data

Volume –II

Section – 10

Technical Specifications

Index

Para Description Page No.

No.

General 1

1 Specifications for RCC Items of Aqueduct 2

1. Material for Concrete 2

1.1 Composition of Concrete 2

1.2 Cement 2-3

1.3 Admixtures 4-5

1.4 Water 6-7

1.5 Sand 7

1.6 coarse Aggregate 10-11

1.7 Production of Sand and coarse Aggregate 12-13

2. Batching and Mixing of Aggregate 13

2.1 Batching 13-16

2.2 Mixing 16-17

3. Quality of Concrete 19

3.1 Maximum size of Aggregate 19-20

3.2 Mix Proportions 20

3.3 Water -Cement Ratio 20-23

3.4 Consistency 23-24

3.5 Test 24-26

3.6 Designation and classification of concrete Mixes 27-28

3.7 Porous Concrete 28

4. Tolerances For Concrete Construction 29

4.1 General 29-30

4.2 Tolerances for structures 30

4.3 Tolerance in intake structures spillway etc. 31

4.4 Lining of Approach etc. 33-34

4.5 Monolithic siphons and culverts 34

4.6 Anchors, Bends etc. 34

4.7 Concrete Roads, Yards etc. 34-35

4.8 Tolerance for placing reinforcement steel 35

5 Forms for Concrete 40

5.1 General 36-37

5.2 Forms sheathing and lining 37-38

5.3 Plywood form lining 38

5.4 Tongue and groove Sheathing 38

5.5 Uniformity of forming material 38-39

5.6 Forms for warped surface designated for F4 finish 39

5.7 Form Ties 39-40

5.8 Cleaning and oiling forms 40

5.9 Removal of forms 40-41

6 Placing of Concrete 41

6.1 Preparations for placing concrete 41

6.2 Placing of concrete 44

6.3 Placing Temperature 49-50

6.4 Weather Conditions 50

7 Finishes and Finishing of Concrete 50

7.1 General 50-51

7.2 Finishes for formed surfaces 51

7.3 Finishes for unformed surfaces 53-55

7.4 Maximum allowances of irregularities 55-56

7.5 Finishing Recesses 56

8 Protection, Curing and Repair of Concrete 56

8.1 Protection of concrete 56

8.2 Curing of concrete 56-58

8.3 Repair of concrete 59-60

8.4 Dry pack mortar 60-61

8.5 Expensive concrete or mortar 61-62

9 Steel Reinforcement 62

9.1 Scope 62

9.2 Applicable publications 62-63

9.3 Materials 63

9.4 Fabrication 63

9.5 Placing in position 63-64

2 Specifications for Items Other Than RCC for Aqueduct 65

10 Foundation excavation 65

10.1 Scope 65

10.2 Setting out 65

10.3 Clearing 65

10.4 Stripping 65

10.5 Access and haulage roads 66

10.6 Excavation –basic requirements 66-67

10.7 Methods of excavation 67

10.8 Disposal of excavated material 67

10.9 Dewatering 67

11 Backfill 68

11.1 Scope 68

11.2 Location of backfill and production of fill material 68

11.3 Preparation of foundation surface and placement 68

11.4 Gradation requirements 69

11.5 Compaction 69-70

11.6 Subsoil water level 70

12 Water Profing Seals & Joint 70

12.1 Construction Joints 70

12.2 Expansion Joints 70

12.3 Asphalt seals 71-72

12.4 Water swelling rubber sealing material 73-74

12.5 P.V.C water stops 74-75

Annexure –A, Test and Test procedure for PVC Water stops 81-82

3. Earthwork Specifications for Canal 83

1.0 Scope 83

2.0 Planning 83

3.0 Setting Out 83-84

4.0 Clearing 84

5.0 Stripping Loose Material 84

6.0 Excavation 84

6.1 General 84-85

6.2 Excavation - Basic Requirements 85-86

6.3 Method of Excavation 86

6.4 Rock Excavation 86-87

6.5 Disposal of Excavated Material 87

6.6 Preparation of Sub grade 87-88

7.0 Filling Reaches 88

7.1 Definition of Canal Section 88

7.2 Definition of Materials 89-89

7.3 Gradation Requirements 89

7.4 Sources of Fill Materials 89

7.5 Production of Fill Material 89-90

7.6 Fill Placement 90

8.0 Quality Control 94

8.1 General 94

8.2 Field Tests 94-95

8.3 Laboratory Tests 95

8.4 The Data of Various Tests 96

8.5 Location and Periodicity of Field Tests 96-97

9.0 Compaction Equipment 97

10.0 Miscellaneous 98

Appendix-1 100

Appendix-2 101

5. Specifications for Cement Concrete Lining 102

1.0 Scope 102

2.0 Terminology 102

2.1 Compaction 102

2.2 Consolidation 102

2.3 Construction Joint 102

2.4 Expansion Joint 102

2.5 Lip cutting 102

2.6 Slip Form 103

2.7 Sub Grade 103

3.0 Materials 103

3.1 Cement 103

3.2 Aggregates 103

3.3 Water 103

4.0 Preparation of Sub grade 103

4.1 General 103-104

4.2 Preparation of Sub grade in Expansive Soils 105

4.3 Preparation of Sub grade consisting of Rock 105-106

4.4 Preparation of Sub grade consisting of Earth 106

4.5 Anti Salt Treatment 107

5.0 Laying of Concrete Lining 108

5.1 General 108

5.2 Cement Concrete 108

5.3 Slump 108

5.4 Air Entraining Admixture 108-109

5.5 Laying of Sleepers 109

5.6 Laying of Slabs 109

5.7 Mixing 109

5.8 Transporting 109-110

5.9 Placing 110

5.10 Finishing 111-112

5.11 Curing 112

5.12 Testing 112

6.0 Surface Drainage 112-113

7.0 Joints 113

7.1 Expansion Joints 113

7.2 Construction / Contraction Joints 113-114

7.3 Filler 114

5. Specifications for Protection work 115

1.0 Wire Crates 115

2.0 Boulder 115

6. Detail of Drawings & Site investigation Data 118-122

1

GENERAL

The Contractor shall adhere to various elevations (Reduced Levels) as

mentioned in the drawings provided with the bid documents except for

lowest/bottom levels shown in station layout drawings (as these are

indicative only) for which detailed structural design is to be carried out by

the contractor.

All Hydraulic/Structural design shall confirm to latest IS Codes.

The latest IS codes shall supersede the specifications mentioned in the bid

documents, however concurrence for the same shall be obtained from

engineer in charge before making any change in specifications.

The contractor should take other parameters as shown in the relevant

drawings for Structural and Hydraulic design. In case, the Contractor needs

any clarification, he can refer the matter to the Chief Engineer.

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1) Specifications for RCC Items of Aqueduct

SPECIFICATIONS FOR CEMENT

CONCRETE PURPOSE

These specifications for Cement Concrete have been framed to provide

uniformity in the construction of works of Aqueduct. These specifications are to be

adopted both by the Employer and the executing agency.

The specifications proposed are based on the specification 4-AS:

“Specifications for Cement Concrete General” issued by HDO. Suitable modifications

however have been incorporated keeping in view the latest practices. Whenever

reference to Indian Standards are given in these Specifications, these refer to the

latest edition of the relevant Indian Standard.

MATERIALS FOR CONCRETE

1.1 Composition of Concrete

Concrete shall be composed of cement, sand, coarse aggregate, water and

other admixtures, all well mixed and brought to the proper consistency.

1.2 Cement

1.2.1 Specifications

Cement for concrete, mortar and grout shall be ordinary or low heat Portland

cement conforming to relevant IS Code. In case Portland pozzolana cement is to be

used, the same shall conform to IS: 1489 Part-1: 2015 (or latest revision)

“Specification for Portland pozzolana cement, fly ash based,” and must not contain

any other pozzolanic material except fly ash. Fly ash for use as pozzolana shall

conform to IS: 3812-1981 “Specification for fly ash for use as pozzolana and

admixture. (First Revision) Reaffirmed 1999”

A certificate should be obtained from the manufacturer for each consignment

indicating the percentage of fly ash used for that particular batch and certifying that fly

ash conforming to relevant Indian Standards have been used in the manufacture of

Portland pozzolana cement.

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The use of Portland pozzolana cement should be limited to concrete mixes up

to a Grade of M-30. Only ordinary Portland cement should be used for mixes richer

than M-30 and for works where pre-stressed concrete is employed.

1.2.2 Transportation of Cement

Cement shall be transported to Project site in bulk, cartload lots or in bags as

approved by the Employer. Cement shall be checked on the job for contamination or

partial setting due to any accidental exposure to moisture during transit.

1.2.3 Storage of Cement

Storage bins for bulk cement shall be weather tight and shall be so constructed that

there will be no dead storage. If, in the opinion of the S.E. / Director, Inspection and

Control, there is reason to believe that any dead storage exists, bins shall be emptied

completely at least every 120* days. Handling and storage facilities shall be such that

no cement is stored before use for more than 120* days. Should any cement be

unavoidably kept in storage longer than 120* days, it shall be tested and, if found

defective, shall be condemned. Cement stored beyond 180 days shall not be used.

In case of storage of cement in bags, the cement shall be stored in a dry and

water-tight structure with adequate provisions for the prevention of absorption of

moisture. All storage facilities shall be subject to the approval of S.E./Director,

Inspection & Control or his authorized agent and shall be such as to permit easy

access for inspection and identification. The cement which has been stored for 60

(sixty) days or more, shall be used before using cement of lesser age. Cement stored

beyond 120* days from the date of manufacture by the manufacturer, shall be tested

and rejected if found defective in anyway. Ordinary Portland cement and Portland

pozzolana cement shall be stored separately.

Cement should be stored at least 18 inches (45 cm) above the natural surface

of the ground. Cement shall not be stored in contact with walls. Cement should be

stacked not more than ten layers high to prevent bursting of bags in the bottom layers

and formation of clods.

* If in the opinion of S.E./ Director, Inspection & Control, it is found that storage has not been done as per specifications laid out here or relevant IS Code ,the period may be reduced to 90 days or less.

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1.2.4 Inspection

Sampling and testing of cement shall be done in accordance with relevant

Indian Standard Specifications. In case of Portland pozzolana cement, quality control

should be more effectively enforced. Immediately on receipt of each consignment of

cement, tests should be carried out for its various properties as per relevant Indian

Standard Codes. The 3 days, 7 days and 28 days compressive strength of Portland

pozzolana cement should be same as specified in Para 7.4.1 of IS: 1489 Part 1: 2015

(or latest revision) which should be tested in the project laboratory before use. If test

results do not conform to IS standards, the matter should be taken up with the agency.

No cement shall be used until notice has been given by the S.E./ Director, Inspection

& Control or his authorized agent that test results conform to IS requirements. If the

tests prove that cement which has been delivered is unsatisfactory, it shall be

promptly removed from the site of work and should not be used on any work on the

project.

1.2.5 Vibration

It should be ensured that a heavy duty vibrating screen is in place over the

discharge into the air slide. The screen size shall be 4 mm. All cement or foreign

material retained on the screen shall be wasted.

1.2.6 Testing of cement at site

The tests to be conducted on site by the Employer on a routine basis are:

- Time of set

- False set

- Compressive strength

- Fineness

1.3 Admixtures

1.3.1 Accelerators

The early strength of concrete can be increased by inclusion of an accelerator,

such as calcium chloride, in the concrete mix. However, such admixtures shall be

used only upon written approval of the Employer covering the type, amount and

location of use. The use of calcium chloride shall not be permitted in concrete in which

reinforced steel/any other metal work is to be embedded. The amount of

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accelerator used shall be no more than that necessary to produce the desired results.

Calcium chloride shall not be used in excess of 2% by weight of the cement. Calcium

chloride shall be measured accurately and shall be added to the batch in solution in a

portion of the mixing water. Use of calcium chloride in the concrete shall in no way

affect compliance with the requirements of these specifications governing protection

and curing of the concrete. Special precautions shall be taken to avoid delay in

handling and placing of concrete when accelerator are used.

Accelerating admixtures, whenever used, shall conform to the requirements of

IS: 9103-1999 reaffirmed 2018 (or latest revision) “Specifications for Admixtures for

Concrete”.

1.3.2 Air-entraining Agents

An air-entraining agent shall be used in all concrete. The agent used shall

conform to IS: 9103-1999 reaffirmed 2018 (or latest revision), “Specifications for

Admixtures for Concrete”, except that the limitation and test on bleeding by concrete

containing the agent shall not apply. The agent shall be of uniform consistency and

quality within each container. The air-entraining admixtures shall be added to the

batch in solution in a portion of the mixing water. The solution shall be maintained at

uniform strength and shall be batched by means of a mechanical batcher capable of

accurate measurement of the agent, throughout the batch during the specified mixing

period. When calcium chloride is being used in concrete, the portion of the mixing

water containing the air-entraining agent shall be introduced separately into the mixer.

The amount of air-entraining agent used in each concrete mix shall be such as

will affect the entrainment of the percentage of air in the concrete as discharged from

the mixer in accordance with the following table:

Coarse Aggregate max.

Size in mm

Total air percent, by Volume, of concrete

20

40

80

5.0±1

4.0±1

3.0±1

6

The quantity of air as tabulated above shall be changed as directed by the

Employer, whenever such change is deemed necessary to meet the varying

conditions encountered during construction.

1.3.3 Water-reducing, Set-retarding Agent

The water reducing, set-retarding agent, if its use as an admixture is approved,

shall conform to IS:9103-1999 reaffirmed 2018 (or latest revision). The agent shall be

of uniform consistency and quality within each container and from procurement to

procurement.

The amount of water-reducing, set-retarding agent used in each concrete batch

shall be determined by laboratory tests.

The water-reducing, set-retarding agent shall be measured for each batch by

means of a reliable mechanical dispenser. The agent, in a suitably diluted form, may

be added to water containing air-entraining agent for the batch, provided the agents

are compatible with each other. The agent can also be introduced separately to the

batch in a portion of the mixing water.

1.3.4 Banning of Powdered Admixtures

Powdered admixture shall not be used nor any admixture which requires any

processing other than measurement prior to use.

1.4 Water

The water used in concrete, mortar and grout shall be clean and free from

objectionable quantities of silt, organic matter, alkalis, acids, oil or other impurities

which are injurious to concrete. Potable waters are generally considered satisfactory

for mixing and curing concrete.

Where water can be shown to contain any sugar or an excess of acid, alkali or

salt, the Employer may refuse to permit its use. The following concentrations

represent the maximum permissible values of sugar, acid, alkali or salt:

a. To neutralize 200 ml sample using phenolphthalein as an indicator, it should not require > 2 ml of 0.1 normal NaOH

b. To neutralize 200 ml sample using mixed indicator, it should not require > 10 ml of 0.1 normal HCl.

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c. Percentage of solids should not exceed the following:-

Organic 0.02 percent

Inorganic 0.30 percent

Sulphates 0.05 percent.

Alkali Chlorides 0.10 percent.

In case of doubt the Employer may require that concrete mixed with water

proposed to be used should not have a compressive strength lower than 90% strength

of the concrete mixed with distilled water.

1.5 Sand

1.5.1 General

The term “sand” is used to designate aggregate in which the maximum size of

particles is 4.75 mm. Sand for concrete, mortar and grout shall be natural sand or

crushed rock or a mixture of natural sand and crushed rock. Sand, as delivered to the

batching plant, shall have reasonably uniform and stable moisture content.

1.5.2 Quality

Sand from natural sources shall consist of siliceous material having hard,

strong, durable, uncoated particles free from injurious amounts of dust, lumps, soft or

flaky particles, shale, alkali, organic matter, loam, mica and other deleterious

substances.

Manufactured sand shall consist of crushed stone, gravel or other inert

materials having hard, strong, durable, uncoated particles, free from injurious amounts

of dust, lumps, soft or flaky particles and other deleterious substances.

The maximum percentage of deleterious substances in the sand, as delivered

to the mixer, shall not exceed the following values.

S. No.

Deleterious substance

Fine aggregate percentage by weight max.

Uncrushed Crushed

I

II

Coal and lignite.

Clay Lumps

1.00

1.00

1.00

1.00

8

III

IV

V

VI

Material Finer than 75-μm IS Sieve

Soft fragments.

Shale

Total of percentages of all the deleterious materials (except mica) including S. No. (I) to (V) for col. 3 and S. No. i to ii for col 4 only

3.00

--

1.00

5.00

15.00

---

--

2.00

NOTES:

1. The presence of mica in the fine aggregate has been found to reduce

considerably the durability and compressive strength of concrete and further

investigations are underway to determine the extent of the deleterious effect

of mica. It is advisable, therefore, to investigate and make suitable

allowances for the possible reduction in the strength of concrete or mortar.

2. The aggregate shall not contain harmful organic impurities (tested in

accordance with IS:2386 Part II-1963 reaffirmed 2016) in sufficient

quantities to affect adversely the strength or durability of concrete. A fine

aggregate which fails in the test for organic impurities may be used provided

that when tested for the effect of organic impurities on the strength of

mortar, the relative strength at 7 and 26 days reported in accordance with

IS:2386 Part-II-1963 is not less than 95%.

3. The sum of the percentages of all deleterious substances shall not exceed

5% by weight. Sand producing a colour darker than the standard in the

colorimetric test for organic impurities (Designation 14) may be rejected.

Sand having a specific gravity (Designation 9, saturated surface-dry-basis)

of less than 2.50 may be rejected. The sand may be rejected if the portion

retained on No. 50 ASTM Screen (IS Sieve 300 micron) when subjected to

5 cycles of the sodium sulphate tests for soundness (Designation 19),

shows a weighted average loss of more than 10% by weight. The

designations in parentheses refer to methods of tests described in the

U.S.B.R. “Concrete Manual”.

9

1.5.3 Grading

The sand, as batched, shall be well graded and when tested by means of

Standard Screen Conforming to IS:460-1985, shall conform to following limits:-

IS Sieve as per IS:460-

1985

Percentage passing for

Grading Grading Grading Grading Zone-I Zone-II Zone-III Zone-IV

10 mm

4.75 mm

2.36 mm

1.18 mm

600 micron

300 micro

n

150 micron

100

90-100

60-95

30-70

15-34

5-20

0-10

100

90-100

75-100

55-90

35-59

8-30

0-10

100

90-100

85-100

75-100

60-79

12-40

0-10

100

95-100

95-100

90-100

80-100

15-50

0-15

10

NOTES: For crushed stone sand the permissible limit on IS sieve 0.150 mm is

20%

1. Fine aggregates complying with the requirements of any grading Zone in

this table is suitable for concrete but the quality of concrete produced will

depend upon a number of factors including proportions.

2. Where concrete of high strength and good durability is required, fine

aggregate conforming to any one of the four grading Zones may be

used, but the concrete mix should be properly designed.

3. It is recommended that fine aggregate conforming to grading Zone IV

should not be used in reinforced concrete unless tests have been made

to ascertain the suitability of proposed mix proportions.

In addition to the grading limits shown above, the sand as delivered to the

mixer shall have a fineness modulus of not less than 2.20.

1.6 Coarse Aggregate

1.6.1 General

The term “Coarse Aggregate” for the purposes of these specifications

designates aggregate of sizes ranging from 4.75 mm to 80 mm or any size or range of

sizes within such limits. The coarse aggregate shall be reasonably well graded within

the nominal size ranges as specified later in this paragraph.

Coarse aggregate for concrete shall consist of natural gravel or crushed rock or

a mixture of natural gravel and crushed rock and shall conform to either IS:383 - 2016

(or latest revision) “Specification for Coarse and Fine Aggregate from Natural Sources

for Concrete”.

Manufactured aggregate shall consist of crushed stone which is produced by

the artificial crushing of rocks, boulders or large cobble stones. Coarse aggregate, as

delivered to the batching plant, shall have uniform and stable moisture content.

1.6.2 Quality

The coarse aggregate, natural or manufactured, shall consist of clean, hard,

dense, durable, uncoated rock fragments. The percentage of deleterious substances

in any size of coarse aggregate, as delivered to the mixer, shall not exceed the

following values:-

11

Coarse aggregate % by weight

S. Deleterious substance

max.

No.

Uncrushed

crushed

i Coal and lignite. 1.00 1.00

ii Clay Lumps 1.00 1.00

iii Material Finer than 75 micron 3.00 3.00 Sieve

iv Soft fragments. 3.00 ---

V Shale -- --

vi Total of percentages of all 5.00 5.00 deleterious materials (Except mica) including S. No. (i) to (v) for col. 3 and 4.

NOTES :

12

The aggregate shall not contain harmful organic impurities (tested in

accordance with IS:2386 Part II-1963) in sufficient quantities to affect adversely the

strength or durability of concrete. The sum of the percentage of all deleterious

substances in any sizes, as delivered to the mixer, shall not exceed 5% by weight.

Coarse aggregate may be rejected if it fails to meet the specifications of IS: 383 - 2016

and following test requirements:-

Specific gravity (Designation 10) - if the specific gravity (saturated surface-

dry basis) is less than 2.50.

The designation in parentheses refers to methods of tests described in the U.S.B.R.

“Concrete Manual”.

1.6.3 Separation

The coarse aggregate shall be separated into nominal sizes and shall be

graded or batched (U.S.B.R. “Concrete Manual” Designation-5) as follows:

Designation of size

20 mm

40 mm

80 mm

Nominal size range Min % retained on screens

indicated

4.75 mm to 20 mm 50% on 10 mm

30 mm to 40 mm 25% on 31.5 mm

40 mm to 80 mm 25% on 63 mm

The screen sizes correspond to ASTM Standards (ASTM Designation 11.61) and in mm to Indian Standards (IS:460-1985 reaffirmed 2018).

Grading of coarse aggregate and all-in aggregate shall conform to Table 2 &

Table 5 respectively of IS: 383 - 2016.

1.7 Production of Sand and Coarse Aggregate

1.7.1 Source of Aggregate

Sand and coarse aggregate for concrete, sand for mortar and grout and raw

materials for manufacturing sand and coarse aggregate shall be obtained from any

approved source. The suitability of the available material will be established by

obtaining samples from the source and subjecting them to prescribed tests in the

laboratory.

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1.7.2 Developing Aggregate Deposits

The area of the deposits from which aggregates are to be produced shall be

carefully cleared of trees, roots, brush, sod, soil, unsuitable sand, gravel and other

objectionable matter.

1.7.3 Processing Raw Materials

Processing of the raw material from sand and gravel deposits will include

quarrying, crushing, screening, washing and blending, supplemented by such other

processing operations as may be necessary to produce sand and coarse aggregate

meeting the requirements of paragraphs 1.5 & 1.6.

2. BATCHING AND MIXING OF CONCRETE

2.1 Batching

2.1.1 General

The batching equipment shall be such as to accurately determine and control

the prescribed amounts of various constituents materials for concrete, viz. water,

cement, admixtures, sand and each size of coarse aggregate entering each batch of

concrete shall be determined by separate weighing. Cumulative batching may be

adopted for small jobs with the approval of the Employer. For further details, see

clause 10.2 of IS: 456-2000 reaffirmed 2016 and clause 4.6 of IS: 457-1957 reaffirmed

2014. Batching plant should confirm to IS 4925-1968.

Necessary precautions should be taken to ensure adjustments to be applied for

the water absorption and surface moisture of aggregate. For determination of these

adjustments, reference may be made to IS: 2386 (Part III) – 1963 reaffirmed 2016,

“Methods of test of aggregate for concrete: Part III specific gravity, density, voids,

absorption and bulking.”

Batch bins shall be constructed so as to be self-cleaning during drawdown and

the bins shall be drawn down until they are practically empty at least 3 times per week.

Materials shall be deposited in the batch bins directly over the discharge gates. The

40 mm and 80 mm coarse aggregate shall be deposited in the batcher bins through

effective rock ladders when the distance through which the aggregates would fall is

greater than 120 cm. To minimizes breakages, the method used in transporting the

aggregate from a higher to a lower elevation shall be such that the aggregate will

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roll and slide with a minimum amount of free fall. Equipment for conveying batched

materials from the batch hopper or hopper to and into the mixer shall be such that

there will be no spillage of the batched materials or overlap of batches. Equipment for

handling Portland cement in the batching plant shall be such as to prevent noticeable

increase of dust in the plant during the discharging of each batch of material. If the

batching and mixing plant is enclosed, exhaust fans or other suitable equipment for

removing dust shall be installed.

When bulk cement and aggregates are hauled from a central batching plant to

the mixers, the cement for each batch shall either be placed in an individual

compartment which, during transit, will prevent the cement from intermingling with the

aggregates and will prevent loss of cement, or be completely enfolded in and covered

by the aggregates by loading the cement and aggregate for each batch

simultaneously into the batch compartment. Each batch compartment shall be of

sufficient capacity to prevent loss in transit and to prevent spilling and intermingling of

batches as compartments are being emptied. If the cement is enfolded in aggregates

containing moisture, and delays occurs between filling and emptying the

compartments, extra cement shall be added to each batch in accordance with

following schedule :-

Hour of contact between cement and wet aggregate

Additional cement required

0 to 2

2 to 3

3 to 4

4 to 5

5 to 6

Over 6

0 percent

5 percent

10 percent

15 percent

20 percent

Batch will be rejected

2.1.2 Equipment

The weighing and measuring equipment shall conform to the following:-

IS:2722-1964 reaffirmed 2016 “Specifications for Portable Swing Weigh Batchers for

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Concrete (Single and Double Bucket Type)” or IS:1791 - 2020 “General Requirements

for Batch Type Concrete Mixers”.

a. The construction and accuracy of the equipment shall conform to the applicable

requirements for such equipment, except that an accuracy of 0.4% over the

entire range of equipment will be required as per IS: 4925-2004 reaffirmed 2015

“Specifications for Concrete Batching and Mixing Plant.” Standard test weights

and any other auxiliary equipment shall be available for checking operating

performance of each scale. Periodic tests shall be made to test the accuracy of

the weighing equipment involved in the batch operations. Such tests will be made

at least every two weeks in the case of equipment for measuring water, cement,

and admixtures and at least once every month in the case of equipment for

measuring sand and coarse aggregates. Such adjustments, repairs, or

replacements shall be made as may be necessary to meet the specified

requirements for accuracy of measurements.

b. Each weighing unit shall be equipped with a visible spring less dial which will

register the scale load at any stage of the weighing operation from zero to full

capacity. The weighing hoppers shall permit the convenient removal of

overweight materials in excess of the prescribed tolerances. The scales shall be

inter-locked so that a new batch cannot be started until the weighing hoppers

have been completely emptied of the last batch and the scales are in balance.

c. The batching equipment shall include an accurate recorder for making a

continuous visible combined record on a single chart of the separate

measurement of each concrete ingredient including all mixing water, air-

entraining agent, and water-reducing, set retarding agent. A portion of the

recorder chart equivalent to at least 30 minutes of plant operation shall include

facilities for automatically registering on the chart the time of day at intervals of

not more than 15 minutes.

d. The equipment shall be capable of ready adjustment for compensating for the

varying weight of any moisture contained in the aggregates and for changing the

mix proportions.

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e. The equipment shall be capable of controlling the delivery of material for

weighting so that the combined inaccuracies in feeding and measuring during

normal operation will not exceed 1% for water; 1.5% for cement; 3% for

admixtures; 2% for sand, 20 mm and 40 mm coarse aggregate for admixtures

and 3% for 80 mm coarse aggregate.

f. The operating mechanism in the water-measuring device shall be such that

leakages will not occur when the valves are closed. The water measuring device

shall be constructed so that the water will be discharged quickly and freely into

the mixer without objectionable dribble from the end of discharge pipe. In addition

to the water-measuring device, there shall be supplemental means for measuring

and introducing small increments of water into each mixer when required for final

tempering of the concrete. This equipment shall introduce the added water well

into the batch.

g. Dispensers for air-entraining agents (calcium chloride solutions) and water-

reducing, set-retarding agents shall have sufficient capacity to measure at one

time the full quantity of the properly diluted solution required for each batch and

shall be maintained in a clean and freely operating condition. Equipment for

measuring shall be designed for convenient confirmation of the accuracy of the

measurement for each batch and shall be so constructed that the required

quantity can be added only once to each batch.

2.2 Mixing

Concrete shall be mixed in a mechanical mixer. The mixer shall comply with the

requirements of IS: 1791- 2020 “Specifications for batch type concrete mixer.”

The mixer shall be tested for its mixing efficiency in accordance with the

method specified in IS: 4634-1991 reaffirmed 2014 “Method for testing the

performance of batch type concrete mixer.” For details of mixing efficiency refer clause

26 of IS: 1791- 2020. Mixing process shall be in accordance with clause 4.7 of IS:

457-1957 reaffirmed 2014. The mixing shall be continued until there is uniform

distribution of materials and mass is uniform in colour and consistency.

Mixers in centralized batching and mixing plants shall be arranged, so that

mixing action in the mixers can be observed from a location convenient to the mixing

17

plant operator. In such plants, the consistency of concrete during the mixing process

shall also be recorded on the chart as mentioned in Para 2.1.2(c).

Mixers shall not be loaded in excess of their rated capacity. Each mixer shall be

equipped with a mechanically or electrically operated timing and signaling (or locking)

and metering device which will indicate and assure the completion of the required

mixing period and will count the batches.

Truck mixers will be permitted by the S.E. / Director, Inspection and Control

only when the mixers and their operation are such that the concrete throughout the

mixed batch and from batch to batch is uniform with respect to consistency and

grading. Any concrete retained in truck mixers which requires additional water to

permit satisfactory placing shall be wasted.

2.2.1 Adequacy of Mixing

The concrete ingredients shall be mixed thoroughly in batch mixers of approved

type & size and designed so as to positively ensure uniform distribution of all of the

component materials throughout the mass at the end of the mixing period. The

adequacy of mixing will be determined by mixer performance tests in accordance with

Designation 26 of the U.S.B.R. “Concrete Manual” or IS: 4634-1991 reaffirmed 2014

“Methods for Testing Performance of Batch Type Concrete Mixers”, as approved by

the Employer. Mixers, when tested, shall meet the following criteria:-

a. The unit weight of air-free mortar in samples taken from the first and last

portions of the batch as discharged from the mixer shall not vary more than

0.8% from the average of the two mortar weights.

b. For any one mix, the average variability for more than one batch shall not

exceed the following limits:-

No of Average variability (% based on tests average mortar weight of all Tests.)

3 0.6

6 0.5

20 0.4

90 0.3

18

c. The weight of coarse aggregate per 0.03 cubic meters in samples taken from

the first and last portions of the batch as discharges from the mixer shall not

vary more than 5% from the average of the two weights of coarse aggregate.

2.2.2 Mixing time

Concrete shall be mixed in a mechanical mixer. The mixer should comply with

IS: 1791 and IS: 12119 reaffirmed 2018. The mixer shall be fitted with water

measuring devices. The mixing shall be continued until there is a uniform distribution

of the materials and the mass is uniform in colour and consistency. If there is

segregation after unloading from the mixer, the concrete should be re-mixed. The

mixing time for each batch after all materials, except the full amount of water, are in

the mixer, provided that all the mixing water shall be introduced before one-fourth the

mixing time has elapsed, shall be as follows:-

Capacity of mixer Time of mixing

1.5 cubic meters or less 1.5 minutes




4.5 cubic meters of less 3.0 minutes

The minimum mixing periods specified are based on proper control of the

speed of rotation of the mixer, and of the introduction of the material, including water

into the mixer. Mixing time shall be increased if and when the charging and mixing

operations fail to produce a concrete batch which conforms throughout with the

foregoing requirements with respect to adequacy of mixing.

2.2.3 General Requirements for Mixing

The concrete, as discharge from the mixer, shall be uniform in composition and

consistency throughout the mixed batch, and from batch to batch except where

changes in composition or consistency are required. Water shall be admitted prior to,

and following the mixer charging operations. Excessive over mixing requiring addition

of water to preserve the required concrete consistency will not be permitted. Any

19

mixer that at any time produces unsatisfactory results shall be repaired promptly and

effectively.

Mixers in centralized batching and mixing plants shall be arranged so that

mixing section in the mixer can be observed from a location convenient to the mixing

plant operator‟s station. In such plants the consistency of concrete during the mixing

process shall also be recorded on the chart as mentioned in Para 2.1.2. (c).

Mixers shall not be loaded in excess of their rated capacity. Each mixer shall be

equipped with a mechanically or electrically operated timing and signaling or locking

and metering device which will indicate and assure the completion of the required

mixing period and will count the batches.

Truck mixers will be permitted only when the mixers and their operation are

such that the concrete throughout the mixed batch and from batch to batch is uniform

with respect to consistency and grading. Any concrete retained in truck mixers which

requires additional water to permit satisfactory placing shall be wasted.

3. QUALITY OF CONCRETE

3.1 Maximum Size of Aggregate

The maximum size of coarse aggregate in concrete for any part of the work

shall be the largest of the specified sizes, the use of which is practicable from the

standpoint of satisfactory consolidation of the concrete by vibration. In general, criteria

laid down in clause 3.4 of IS: 457-1957 reaffirmed 2014 and clause 5.3.3 of IS: 456-

2000 reaffirmed 2016 shall be followed.

Except where it is determined by the Employer that due to closely spaced

reinforcement or other reasons, the use of smaller maximum size aggregate is

necessary to obtain satisfactory placement of the concrete, the maximum size

aggregate shall be as under:-

a. In general 20 mm aggregate is suitable. Where there is no restriction to the flow

of concrete into sections, 40 mm or larger size may be permitted, but not

exceeding 80 mm.

b. In general, the following criteria will hold for deciding the maximum size of

aggregate:-

20

i) One-fourth the narrowest dimensions between the faces of forms,

ii) One-third the depth of a slab,

iii) Three-fourths of the clear space between reinforcement bars,

iv) Three-fourths of the narrowest space through which the concrete shall

have to pass.

3.2 Mix Proportions

The proportions in which the various ingredients are to be used for different

parts of the work shall as determined from time to time during the progress of the work

and as tests are made of samples of the aggregate and the resulting concrete. The

mix proportions and appropriate water-cement ratios shall be determined by the

Employer on the basis that the concrete shall have suitable workability, density,

impermeability, durability and required strength without the use of an excessive

amount of cement. Tests for the concrete shall be performed and the mix proportions

shall be adjusted whenever necessary for the purpose of securing the required

economy, workability, density, impermeability, durability or strength. If Portland

pozzolana cement is to be used, the design mixes should be determined separately

and the design mixes of the ordinary Portland cement should not be used for it.

For design of mix, reference may be made to IS: 10262-2019 “Recommended

Guidelines for concrete mix design.” For the initial design of mix, value of standard

deviation corresponding to „good‟ degree of control may be adopted as given in Table

1 of IS: 10262-2019 after getting experience and field data this value can be modified

if considered necessary.

3.3 Water –Cement Ratio

The water-cement ratio will be regulated by the requirements of workability, strength

and durability. In general, water cement ratios for a given strength of concrete will be

determined by laboratory tests. In the absence of tests data on the material to be used

in the concrete, the water-cement ratio for a given strength of concrete shall not

exceed the values given in Table 3.1.

The climatic conditions have a direct bearing on the durability of concrete

surfaces. Table 3.2 gives allowable maximum net water-cement ratios (exclusive of

21

water absorbed by the aggregates) for durability of concrete subject to various

degrees of exposure. The lower of the following two water-cement ratios should be

used in mix design s:-

a) that required for strength as determined by tests or from Table 3.1 or

b) that required for durability, as determined by tests or from Table 3.2

TABLE -3.1

Specified compressive strength at *28 days in kg/cm2

Maximum permissible water-cement Ratio by weight

Non-air entrained Air-entrained Concrete ** Concrete **

175

200

250

275

300

350

0.65

0.58

0.51

0.44

0.38

0.31

0.54

0.46

0.40

0.35

0.30

+

* 28 days of strength for ordinary Portland cement and 7 days for rapid hardening cement.

+ For strengths other than those indicated, proportions shall be selected on the basis of laboratory trials.

** The ratios given are laboratory/field tests.

only indicative; actual proportions shall be based on The values include surface moisture in aggregates.

22

TABLE- 3.2

Allowable maximum net water-cement ratio for durability of concrete

Type or location of concrete or structure and degree of exposure A

Water-cement ratio by weight

B

a) All exposed concrete structures including 0.55 ±0.02 Aqueduct

b) Concrete in structures or parts of 0.58 ± 0.02 structures to be covered with back-fill or to

be continually submerged or otherwise protected from the weather such as cut off walls, foundations, parts of sub-structures.

c) Concrete that will be subject to attack by 0.50 ± 0.02 sulphates, alkalis in soil and ground waters.

d) Concrete deposited by tremie in water 0.45 ± 0.02

e) Canal lining 0.58 ± 0.02

NOTES:-

1. For concrete not exposed to weather, such as the interior of buildings and

portions of structures entirely below ground, no exposure hazard is involved and

the water content will be selected on the basis of strength and workability

requirement.

2. In working out water ratio, pozzolana, if any used, shall be assumed to be part of

cement.

3. In calculating the water-cement ratio, the amount of water shall be total weight of

water in mix, including all free water in the aggregate but not including any

moisture absorbed by then. The surface moisture shall be determined in

accordance with Designation 11 as U.S.B.R. “Concrete Manual” or IS: 2386 (Part-

III)-1963 reaffirmed 2016 “Methods of Tests for Aggregate for Concrete.” In at

absence of data the amount of surface water may be estimated from the values

given in Table 3.3.

23

TABLE-3.3

Surface water carried by average aggregate.

Aggregate

Approx. Quantity of surfaces water liters/cu

meter.

Very wet sand.

Moderate wet sand.

Moist sand.

* Moist gravel or crushed rock

120

80

40

20 to 40

*Coarser the aggregate, the less water it will carry.

3.4 Consistency

The proportion of aggregate to cement for any concrete shall be such as to

produce a mix which can work readily into the corners and angles of the forms and

around reinforcement bars with the method of placing employed on the work, but

without permitting the materials to aggregate or excess free water to collect on the

surface.

The amount of water used in the concrete shall be regulated as required to

secure concrete of the proper consistency and to adjust for any variations in the

moisture content or grading of the aggregates as they enter the mixer. Addition of

water to compensate for stiffening of the concrete before placing will not be permitted.

Uniformity in concrete consistency from batch to batch will be required. Each mixer

shall be equipped with a consistency meter that will provide a reliable continuous

indication of concrete consistency and record in on the combined autographic recorder

chart described in paragraph 2.1.2(c). The sensitivity of the consistency meters shall

be such that the effect of a change in slump of 12 mm shall be readily discernible to

the operator and the range of the meters shall be sufficient to include a slump of as

little as 25 mm. The design and construction of the consistency meters shall be such

as to eliminate appreciable errors in indicated consistency that would result from

friction in the mixer operation and variations in power input.

24

The slump, as a measure of concrete consistency shall be maintained fairly

uniform at the point of placement. When the mixer is at a considerable distance from

the form, slumps should be taken occasionally on the same batch at the point of

placement to determine the slump loss in handling. Compensation for excessive

slump loss, by allowing wetter consistency at the mixer with consequent higher water

and cement contents and increased aggregation in transit, should not be permitted.

The allowable slump loss in transit shall not exceed 25 mm.

The slump of the concrete after the it has been deposited but before it has been

consolidated, shall not exceed 50 mm for heavy mass concrete structures, the tops of

walls, piers, parapets and curbs, and for slabs that are horizontal or nearly horizontal;

100 mm for concrete in pumped or air-placed concrete, in side walls and; and 75 mm

for all other concrete. The Employer may require a lesser slump whenever concrete of

such lesser slump can be consolidated readily into place by means of the vibration

specified in paragraph 6.2. The use of buckets, chutes, hoppers or other equipment

which will not readily handle and place concrete of such lesser slump will not be

permitted.

The slump shall be measured in accordance with the method prescribed in

Designation 22 of the U.S.B.R. “Concrete Manual” and IS: 1199-1959 reffirmed

2018“Method of Sampling and Analysis of Concrete.”

3.5 Tests

3.5.1 Sampling Fresh Concrete

Samples from fresh concrete shall be taken as per IS: 1199-1959 reaffirmed

2018, and cubes shall be made, cured and tested at 28 days in accordance with IS:

516- part 4: 2018. Samples for strength tests of each class of concrete shall be taken

neither less than once a day nor less than once every 115 cubic meter of concrete or

for each 465 m2 of surface area placed. Sampling from chutes, conveyors and

transporting containers shall be avoided. Sample will be taken from concrete after it

has been placed and vibrated in the forms. Samples taken from air entrained concrete

shall be hand rodded in moulds to disturb the air content as little as possible. Samples

taken from the mixers or from chutes, conveyors, transporting containers, etc.,

whenever unavoidable, will be vibrated in the moulds to simulate the vibrations given

in the forms.

25

Separate portions of the samples shall be used for slump and unit weight tests

and for casting the cylinders/cubes. For slumps tests or compressive strength tests,

aggregate in concrete larger than 40 mm shall be removed by wet-screening or hand-

picking. However for air-entrained concrete the over-size aggregate shall be removed

by hand picking and not by wet screening. For larger cylinders/cubes, the maximum

size of aggregate left in the samples shall not be more than one-fourth the diameter of

the cylinder or cube dimension. The hand-picked concrete shall be remixed with a

shovel into a uniform mass before making slump tests or test specimens for

compressive strength. Occasional specimens as large as can be tested in the field

laboratory shall be cast without removing any aggregates. Such specimens shall be

tested to establish the relation between un-screened and normally screened samples.

The corrective factors thus determined shall be applied to the tests strength of

screened specimens in recording the average daily unit.

Slump tests and cylinder/cube specimens shall be made without delay after

sampling, as a delay of even 15 minutes may decrease the slump as much as 50%.

Samples for strength tests of each class of concrete shall be taken at least one from

each shift and in accordance with the following:

Quantity of

concrete in the work No. of samples

m3

1-5 1

6-15 2

16-30 3

31-50 4

>= 51 4 + one for each additional 50

m3 or part thereof.

3.5.2 Securing Hardened Specimens of Concrete from Structures

The procedure for securing, preparing and testing specimens of hardened

concrete from structures shall be in accordance with Designation 2 of the U.S.B.R.

26

“Concrete Manual” and Appendix „B‟ of IS: 457-1957, and IS: 1199-1959. The cores

from hardened concrete will be extracted from concern at such ages and locations as

directed by S.E./Director, Inspection & Control or his authorized agent. In general, the

concrete shall be 14 days old or older before the specimens are removed. Specimens

that show abnormal defects or that have been damaged in removal shall not be used.

A core specimen for the determination of compressive strength shall have a

diameter at least three times the maximum nominal size of the coarse aggregate used

in the concrete and in no case shall be final diameter of the specimen be less than

twice the maximum nominal size of the coarse aggregate. The length of the specimen,

when capped, shall be as nearly as practicable twice its diameter.

3.5.3 Testing

In general strength tests acceptance criteria inspection & testing on concrete

shall be in accordance with the provision of clause 15.1 to 17 of IS: 456-2000

reffirmed 2016.

The compressive strength of the concrete will be determined by testing 15 cm *

50 cm cylinder made and tested in accordance with Designation 29 to 33 of the

U.S.B.R. “Concrete Manual” or IS: 516-1959 “Methods of Tests for Strength of

Concrete” except that, for all concrete samples from which cylinders are to be cast,

the places of coarse aggregates larger than 40 mm will be removed by screening or

hand picking.

Compressive strength will also be determined by testing drilled cores, which will

be extracted from concrete at such ages and locations as may be directed by the

Employer. The cores shall normally be 15 cm or 25 cm in diameter except as

otherwise directed. The cores shall be painted with some legible identification mark.

The cores shall be prepared for testing by cutting the ends to form cylinders, whose

lengths are twice the diameter and by suitable capping, if required, and shall be tested

in the same manner as cast concrete cylinders. The cores shall be tested as soon as

practicable after extraction and shall be kept continuously moist either by wet burlap or

fog room curing until the time of test. The compressive specimens and cores drilled

from the structure shall be used for determining unit weight, specific gravity,

absorption tests and durability.

27

Slump tests will be made in accordance with Designation 22 of the U.S.B.R.

“Concrete Manual” or IS: 1199-1959 “Method of Sampling and Analysing of Concrete”.

3.6 Designation and Classification of Concrete Mixes

The mixes are designated in accordance with IS: 456-1964. The figure

appearing after word „M‟ indicates the strength of concrete mix in kg/cm2. The

maximum size of aggregates is indicated in mm after the dash (-) at the end, such as

“M 20-M-40”.

Specified Permissible stress in

Max. size of compression (kg/cm2 Grade of characteristic

Aggregates

)

Concrete compressive strength in mm

at 28 days in kg/cm2

Bending Direct

M 10 80

40 100 30 25

20

M 15 80

40 150 50 40

20

M 20 80

40 200 70 50

20

M 25 80

40 250 85 60

20

M 30 80

40 300 100 80

20

M 35 80

40 350 115 90

20

M 40 80

40 400 130 100

20

NOTE:-

i) The characteristic strength is defined as the strength of material below which not more than 5 percent of the test results are expected to fail.

28

ii) The characteristic compressive strength shall be measured on 15 cm cube at 28 days expressed in Kg/ cm 2.

iii) Designation of concrete lower than M 20 shall not be used in reinforcement

concrete.

iv) M 5 & M 7.5, of concrete may be used for simple foundations of a masonry walls. These mixes need not be designed.

v) Other properties of concrete shall be in accordance with IS: 456-2000.

vi) Instructions issued by the Employer for sampling and testing of concrete may

also be followed where necessary.

The minimum 28 days compressive strength shown in classifications table shall

be taken as the average of any five consecutive strength tests of the laboratory cured

specimens representing each class of concrete. Average strength tests shall have

values less than the specified strength.

3.7 Porous Concrete

Porous concrete may be placed as a slab under split sewer pipe drains of the

stilling basins and such other features. Porous concrete shall be composed of one part

of cement to 5.5 parts of the coarse aggregate, by weight. The aggregate shall pass

20 mm mesh and be retained on No.4 ASTM screen (IS sieve 4.75 mm). The amount

of water used in the concrete shall be such that the resulting cement paste will not fill

the voids of the aggregates but will thoroughly coat and bind the aggregate particles.

In placing porous concrete, care shall be taken that it is not over tamped or compacted

so as to reduce its porosity. The compressive strength of the porous concrete at 7

days, as determined by tests of 15 cm* 30cm cylinders made and tested in

accordance with the latest standard practice, shall be not be less than 70 kg/cm2. The

porosity of the concrete at 7 days shall be such that water will pass through a slab of

the concrete, 30 mm thick at the rate of not less than 407 liters per minute per sq.

meter of slab, with a constant 10 mm depth of water on the slab. The porous concrete

shall be placed to the grades and dimensions as directed.

3.7.1 PLUMS

The size of plums shall usually be 225 mm to 300 mm (each of 50 kg or more

such as one man can handle). Plums shall be sound and hard having crushing

strength not less than 350 Kg/cm2, and shall be perfectly free from earth or clay or

29

disintegrated matter or any adhering coating and properly washed. They shall not

have sharp corners or soft material embedded in them.

3.7.1.1 PLUM CEMENT CONCRETE

Cement Concrete shall conform to „Specifications for Cement Concrete‟ and

shall be of the specified normal mix. However, plum concrete shall not be used for the

concrete mixes of M-25 or of higher strength.

3.7.1.2 PLACING OF PLUM CONCRETE

During concreting, first 45 to 60 cm thick concrete of the specified nominal mix

shall be laid at the bottom. While the top layer of this concrete is still wet, plums shall

be laid so that they are slightly embedded in the wet concrete. Normally, these plums

will sink-in sufficiently under their own weight in all but dry mixes. If the mix is sloppy,

the placing of the plums should be delayed until the concrete has commenced to

stiffen to avoid undue sinking. Complete submergence shall be avoided and all plums

should be significantly visible before placing the next layer of concrete. The thickness

of the latter and successive layers shall be at least twice of the largest plum. The

plums shall be placed so that the clear distance between any two is not less than the

greatest width or thickness of either of plums. The clear distance between any plum

and the face of the work or reinforcement shall not be less than 15 cm. The plums

shall be carefully placed and not dropped so as to avoid injury to the forms or to the

partially set adjacent concrete. Cement Concrete shall then be inserted in the

interstices and well packed.

It must be ensured that all dripping surface water is removed from the plums

before being embedded in the concrete. If plums of stratified stone are used, they

shall be laid on their natural bed. Care must be taken to ensure that no air is trapped

underneath the stone and the concrete does not work-away from their underside.

4. TOLERANCES FOR CONCRETE CONSTRUCTION

4.1 General

Permissible surface irregularities for the various classes of concrete surface

finish are specified in section 7. These finishes are to be distinguished from tolerance

as described in this section. The intent of this section is to establish tolerances which

are consistent with the construction practice, as well as governed by the effect which

30

the permissible deviations will have upon the structural action or operational function

of the structure.

In case of structure where tolerances are not stated in these specifications,

permissible deviations will be interpreted in conformity with the provisions of this

section. The tolerances set forth herein may however, be diminished if such

tolerances impair the structural action or operational function of a structure.

All concrete structure shall be constructed to the exact lines, grades, and

dimensions. However, inadvertent deviations from the established lines, grades and

dimensions will be permitted to the extent set forth in this section.

If an approved drawing shows specific tolerances in regard to certain

dimensions, these tolerances shall be considered in addition to the tolerances

specified in this section. Concrete work that exceeds the specified tolerance limits

shall be remedied or removed and replaced.

Concrete forms shall be set and maintained sufficiently within the tolerance

limits so as to ensure completed work within the specific tolerance. However, the

forms for the curved sections or in conduits which are to receive an F4 finish shall be

constructed as specified in the relevant section.

4.2 Tolerances for Structures

Tolerances for RCC structures

Variations from the Plumb

Variation from Plumb

In 3 M. ….. 6 mm

a. In the lines and surfaces of In any storey of 6 meters max. 9 columns, piers, walls and in arises. mm

In 12 meters or more 18 mm.

b. For exposed corner columns In any bay or 6 meters max. 6mm control joints grooves, and other In 12 m. or more ...12 mm. conspicuous lines

4.2.1 Variations from the Level

Variations from the level or from the grades indicated on the approved drawings:

31

a. In floors, ceilings, beam soffits, and in arises measured before removal of supporting shores.

In 3 meters...6 mm

In any bay of 6 m. max. 9 mm In 12 meters or more ...18 mm.

b. For exposed lintels, sills, parapets, horizontal grooves, and other conspicuous lines

In any bay of 6 m. max.: 6 mm In 12 m or more : 12 mm

Variations of the linear building lines from

established position in plan and related

position of columns, walls and partitions

In any bay of 6m max 12 mm In 12 m or more .. 25 mm

Variations in the sizes and locations Of sleeves. Floor opening, wall opening

6 mm

Variations in cross-sectional dimensions Minus …. 6 mm of columns and bears and slabs and walls

plus.......12 mm.

4.2.2 Variation in Footings

a. Variations of dimensions in plan

Minus ........-12 mm , +50 mm

b. Misplacement or eccentricity

2 % of the footing width in the directions of misplacement but not more than 50 mm.

c. Reductions in thickness Minus...5 % of specified thickness.

4.3 Tolerance in intake structures etc.

Tolerance in intake structures, bridges and pier are given below:

4.3.1 Intakes Structure Columns

A. variations of dimension from established position Max........ 12mm including distance between opposite columns

B. variations from the plumb for total height of column Max.......... 12 mm

C. variations of dimensions between trash rack slot Minus........ None adjacent columns including tolerance for concrete Plus........ 12 mm

32

constructions & irregularities of finish.

4.3.2 All Other Structures

a. Variations of the constructed liner outline from established positions in plan

In 6 meters.... ± 12 mm and 12 meters..... ± 18 mm

b. Variations of dimensions to individual ...In24meters 36mm. In buried structural features from established position construction twice the above amount.

c. Variations from the plumbed from the In 3 meters.... ± 12 mm. specified better or from the curved surfaces of In 6 meters.... ± 18 mm. all Structures, including the lines and surfaces In 12 m. or more …..± 32 mm. of Columns, walls piers, buttress, arch In buried construction: twice the sections Vertical joint grooves & visible above mentioned. arises.

d. Variations from the level or from the grades In 3 meters.... ± 6 mm. indicated on the approved drawings in slabs, In 19 meters or more…….. ± 12 mm. beams soffits, horizontal joint grooves and In buried construction: twice the visible arises above mentioned.

e. Variations in cross-sectional dimensions of Minus................ 6 mm. columns beams buttresses, piers & similar Plus................. 12 mm. members

f. Variations in the thickness of slabs, walls, Minus................ 6 mm. arch sections and similar members Plus................. 12 mm.

4.3.3 Footings for Columns etc.

Tolerances for footings for columns, piers walls, buttresses and similar members:

a. Variations of dimensions in plan.

Minus...12 mm; Plus......50 mm

b. Misplacement of eccentricity.

2 % of footing width in the direction of misplacement but not more than...50mm

c. Reductions in thickness 5 % of specified thickness

4.3.4 Sills and Side Walls etc.

Tolerances for sills and side walls for gate and similar water-tight joints are given below:

33

a. Variations from the plumb and level. ≤ rate of 3 mm in 3 m. Max. 5 mm.

b. Variations from indicated spacing.

For effective depth 200 mm or less ± 10 mm.

For effective depth more than 200 mm ± 15 mm.

4.3.5 Bridges and Piers

a. Departure from established alignment.

25 mm

b. Departure from established grades. 25 mm

c. Variations from the plumb or the specified batter in the 12 mm, Max 18 lines and surfaces of piers in 3 meters mm

d. Variations from the level or from the grades indicated in 3 M.......12 mm. on the drawings in slabs, beams, horizontal grooves and Max 18 mm. railing offsets.

4.3.6 Variations in Steps

a. In a flight of stairs ........Rise ......3mm;Tread 6mm.

b. In consecutive steps

Rise.........2 mm; Tread......3 mm.

4.4 Lining of Approach etc.

Tolerance for lining of approach and canal, and lining of excavated slopes are given below:


25 mm

b. Departure from established grades and slopes 25 mm

c. Thickness of lining. Minus....5 % of specified thickness.

d. Variations from specified width of section at any 1/4th of 1% plus 12 mm. height

e. Variations from established height of lining 1/2th of 1% plus 25 mm.

34

f. Variations in surfaces. Invert....6 mm in 3 m.

Sides slopes..12 mm in 3 m.

4.5 Monolithic Aqueduct and Culverts


25 mm

b. Departure from established grades and 25 mm Slopes

c. Variations in thickness. At any point.....minus 2.5 % or 6 mm whichever is greater; next any point...... plus 5 % or 12 mm whichever is greater.

d. Variations from inside dimensions. 1/2 or 1 percent

e. Variations in surface. Inverts...6mm in 3 meters Sides slopes...12 mm in 3 m.

4.6 Anchors, Bends etc.

Tolerance for anchors, bends, manholes, turnouts, and similar structures:


25 mm

b. Departure from established grades. 25 mm

c. Variations from the plumb or the Exposed, in 3 meters... ....12 specified better in the lines and surfaces of mm. piers exposed Walls, and in arises. Backfilled in 3 meters ....25 mm

d. Variations from the level or from the Exposed in 3 meters ..... 12 mm grades indicated on the drawings in slabs, Backfilled in 3 meters ....25 mm beams, horizontal grooves and railing offsets.

4.7 Concrete Roads, Yards etc.

Tolerance for concrete roads, parking areas and repair and storage yards :

Departure from established, alignment

35

a. Concrete roads. ± 12 mm

b. Parking areas & Yards. ± 25 mm

Departure from established, longitudinal grade on any line



Departure from established traverse template contour except at traverse joints



Departure from established traverse template contour at traverse joints.

a. Concrete roads in width of one traffic lane ± 6 mm


4.8 Tolerance for Placing Reinforcement Steel

a) Variations of protective covering. With 50 mm cover.. 6 mm. With 75 mm cover..12 mm. With 150 mm cover 25mm

b) Variations from indicated spacing 25 mm provided total steel remains the same

c) for effective depth 200 mm or less 10 mm

d) for effective depth more than 200 mm 15 mm

The cover shall in no case be reduced by more than one third of specified cover

or five mm whichever is less.

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5. FORMS FOR CONCRETE

5.1 General

Forms shall be used, wherever necessary to confine the concrete and shape it

to the required lines, or to ensure against contamination of the concrete by materials

caving or sloughing from adjacent surfaces left by excavations or other features of

work. All exposed concrete surfaces having slopes of 2 to 1 or steeper shall be

formed. Where the side slopes or walls or an excavations for a concrete structure can

be trimmed to the prescribed lines without sloughing, the use of the form will not be

required.

Forms shall be true to lines and grades within the allowable tolerances. Forms

shall have sufficient strength to withstand the pressure resulting from placement and

vibration of the concrete, and shall be maintained rigidly in position. Forms shall be

sufficiently tight to prevent loss of mortar from concrete. Chamfer strips shall be

placed in the corners of forms so as to reduce beveled edges on permanently

exposed concrete surfaces. Interior angles on such surfaces and edges at formed

joints will not require beveling unless requirement for beveling is specially laid down.

Where forms for continuous surfaces are placed in successive units, care shall be

taken to fit the forms over the completed surfaces so as to obtain accurate alignment

of surfaces and to prevent leakage of mortar. All forms shall be so constructed that

they can be removed without hammering or prying against the concrete.

Forms for side walls shall be provided with openings of ample size for

supervision, vibration and inspection. The openings shall be located in the crown and

along two longitudinal lines in each side wall. The openings along the two selected

longitudinal lines in each side wall shall be staggered and shall be spaced at not more

than 2.5 meters on centres along each longitudinal line. Opening in the crown shall be

spaced at not more than 2.5 meters on centers and shall be located alternatively on

each side of the Aqueduct center line.

Forms for concrete surfaces for which finish F3 is specified shall not be

constructed continuously from lift to lift but shall be removed after concrete in a lift has

hardened and reset for the next life. The reset forms shall overlap the hardened

concrete in the lift previously placed by not more than 25 mm and shall be tightened

snugly against the hardened concrete so that, when concrete placement is resumed,

37

the forms will not spread and allow offsets or loss of mortar at construction joints.

Additional bolts or form ties shall be used as necessary to hold reset forms tight

against the hardened concrete.

5.2 Forms Sheathing and Lining

Wood sheathing or lining shall be of such kind and quality or shall be so treated

or coated that there will be no chemical deterioration or discoloration of the formed

concrete surfaces. The type and condition of form sheathing and lining, and

fabrications of forms for finishes F2, F3 and F4 shall be such that the form surfaces

shall be even and uniform. The ability of the forms to withstand distortion caused by

placement and vibration of concrete and the workmanship used in form construction

shall be such that the formed surfaces will conform with the applicable requirements of

these specifications pertaining to finish of formed surfaces. Where F3 is specified, the

sheathing or lining shall be so placed that joints marks on concrete surfaces will be in

general alignment both horizontally and vertically.

Except where otherwise specifically provided, materials used for form sheathing

or lining shall conform to the following requirements:-

Required finish of Formed surface

or lining

Wooden sheathing

Steel sheathing

Steel lining

F1 Any grade Permitted Permitted

F2 Common shiplap or plywood sheathing Permitted Permitted or lining if approved

F3

Common T & G Except where

Plywood lining or sheeting as

specifically required

Not permitted

Not permitted.

F4

For plane surfaces Common T & G shiplap or plywood. For warped surfaces, timber which is free from knots and imperfections and which can be cut and bent accurately the required curvatures without splintering or splitting.

Permitted

Not permitted.

38

* Steel ‘Sheathing’ denotes steel sheets, not supported by a backing of wood boards. Steel ‘lining’ denotes thin steel sheets supported by a backing of wood boards.

* Preferably F4 -Finish is required in Aqueduct including U/s and D/s sloping portions

of Aqueduct to minimize the transition losses.

+ Tongue and grooved.

Lagging that is rough on the side against which concrete is to be placed shall

be used to form inside surfaces of the structures that are to be plastered or to be

covered with terracotta or terrazzo.

5.3 Plywood Form Lining

Plywood shall be used for lining forms for the interior surfaces of the power

plants etc. which are exposed permanently to view. The plywood shall be water-proof,

non-warping, non-wrinkling, concrete from plywood manufactured with special water

resistant glue. In so far as practicable, the plywood sheets shall be of uniform width

and length and shall have a uniform thickness of not less than 16 mm, or not less than

9 mm if backed with shiplap or other approved backing. Tempered water-proof

pressed board or similar approved material not less than 3 mm in thickness may be

used instead of plywood if backed with shiplap or other approved backing. The joints

between the plywood or pressed- board sheets shall be smooth and as nearly perfect

as practicable, and no patching of the plywood or pressed-board lining will be

permitted. Minor imperfections in the plywood or pressed-board lining shall be

corrected by the use of plastic wood secured firmly in place and sand-papered smooth

after it has hardened thoroughly. The use of sheets metal to correct imperfections in

such lining of forms will not be permitted.

5.4 Tongue-and Groove Sheathing

Tongue-and-groove sheathing shall be used for forming interior surfaces of the

Power Plants etc. which are above water or fill level. The tongue-and-groove

sheathing shall be 10 cm or 15 cm, common T & G, and shall be placed horizontally,

provided, that either all 10 cm or all 16 cm timber shall be used.

5.5 Uniformity of Forming Materials

Forms for concrete surfaces required to receive F2 and F3 finishes shall be

constructed so as to produce uniform and consistent texture and pattern on the face of

the concrete. Metal patches on forms for these surfaces will not be permitted. The

39

form sheathing or lining shall be placed so that all horizontal form marks are

continuous across the entire surfaces. If forms are constructed of plywood form lining

or of panels of common timber, the vertical form marks shall be continuous for the

entire height of the surface. If forms are constructed of common timber that are not

panelled, the sheathing shall be cut square and vertical joints in the sheathing shall be

staggered and shall be made only at studs. For these surfaces one type of form timber

for all F2 surfaces and one type of material for all F3 surfaces shall be used, the T & G

timber shall either be 15 cm or all 20 cm timber.

5.6 Forms for Warped Surfaces Designated for F4 Finish

Forms for the transitions in the Aqueduct and other warped surfaces shall be

constructed so as to conform accurately to the required curvatures of the sections.

Dimensions from the center lines of the concrete surfaces shall be given at several

sections throughout the length of the warped surface. Intermediate sections shall be

interpolated as necessary for the type of form construction being used and the forms

shall be constructed so that the curvature will be continuous between sections. Where

necessary to meet requirements for curvature, the form sheathing shall be built up of

laminated splines cut to make tight and smooth form surface.

The form shall be so constructed that the joint marks on the concrete surfaces

inside of principal water conduits shall, as far as possible, follow the line of water-flow.

After the forms have been constructed and erected, all surface imperfections shall be

corrected, all nails shall be hidden and any roughness and all angles on the surfaces

of the forms caused by matching the form materials shall be dressed to the required

curvatures.

5.7 Form Ties

Embedded metal rods used for holding forms shall remain embedded and

except where F1 finish is permitted shall terminate not less than two diameters or

twice the min. dimension of the tie clear of formed faces of concrete. Where F1 finish

is permitted, ties may be cut-off flush with the formed surfaces. The ties shall be

constructed so that removal of end fasteners can be accomplished without causing

appreciable spalling at faces of the concrete. Recesses resulting from removal of ends

of form ties shall be filled in accordance with the provisions for “Repairs of

40

Concrete”. Embedded wire ties for holding forms will be permitted in concrete walls for

which finish F1 is specified, except walls to be subjected to water pressure.

Embedded wire ties will not be permitted in concrete works for which other finishes are

specified. Wire ties shall be set-off flush with the surface of the concrete after the

forms are removed.

5.8 Cleaning and Oiling of Forms

At the time the concrete is placed in the forms, the surface of the forms shall be

free from incrustation of mortar, grout or other foreign material that would contaminate

the concrete or interfere with the fulfillment of the specification requirements relating to

the finish of formed surfaces. Before concrete is placed, the surfaces of the forms

except surfaces of rough timber meant for concrete surfaces which are to be

plastered, shall be oiled with a commercial form oil that will effectively prevent sticking

and will not stain the concrete surfaces. After oiling, surplus oil on the form surfaces

and any oil on the reinforced steel or other surfaces requiring bond with the concrete

shall be removed. For wooden forms form oil shall consist of straight, refined, pale,

paraffin mineral oil. For steel forms, form oil shall consist of refined mineral oil suitably

compounded with one or more ingredients which are appropriate for the purpose.

Special care shall be taken to oil thoroughly the form strips for narrow grooves at

windows, doors and elsewhere so as to prevent swelling of the forms and consequent

damage to the concrete prior to or during the removal of forms

5.9 Removal of Forms

To facilitates satisfactory progress with the specified curing and enable earliest

practicable repairs of surface imperfections, forms shall be removed as soon as the

concrete has hardened sufficiently to prevent damage by careful form removal. Forms

on upper sloping faces on concrete, such as on the water sides of warped transitions,

shall be removed as soon as the concrete has attained sufficient stiffness to prevent

sagging. Any needed repairs or treatment required on such sloping surfaces shall be

performed at once and be followed immediately by the specified curing.

To avoid excessive stresses in the concrete that might result from swelling of

the forms, wood forms for walls openings shall be loosened as soon as this can be

accomplished without damage to the concrete. Forms for the openings shall be

constructed so as to facilitate such loosening. Forms for tunnel lining shall not be

41

removed until the strength of the concrete is such that form removal will not result in

perceptible cracking, spalling, or breaking of edges or surfaces, or other damages to

the concrete. Forms shall be removed with care so as to avoid injury to the concrete

and any concrete so damaged shall be repaired in accordance with the provisions for

“Repairs of Concrete”.

In normal circumstances and where ordinary Portland cement is used, forms

may generally be removed after the expiry of the following periods:-

a) Walls, columns and vertical faces of 24 to 48 hrs. as may be

all structural members decided by the Employer

b) Slabs (props left under) 3 days

c) Beam soffits (props left under) 7 days d)

e)

Removal of props under slabs :

1) Spanning up to 4.5 m 7 days

2) Spanning over 4.5 m 14 days

Removal of props under beams and

arches:

1) Spanning up to 6 m 14 days

2) Spanning 6 – 8 m 21 days

28 days 3) Spanning over 8 m

6. PLACING OF CONCRETE

6.1 Preparations for Placing Concrete

6.1.1 General

No concrete shall be placed until all form work, installation of parts to be

embedded, and preparation of surfaces involved in the placing have been approved

by the officer the Employer. No concrete shall be placed in water except with written

permission of the Employer and the method of depositing the concrete shall be subject

to his approval. Concrete shall not be placed in running water and shall not be

subjected to the action of running water until after the concrete has hardened. All

surfaces of forms and embedded materials that have become encrusted with dried

mortar or grout from concrete previously placed shall be cleaned of all such mortar or

grout before the surrounding or adjacent concrete is placed.

42

6.1.2 Foundations Surfaces

Immediately before placing concrete, all surfaces of foundations upon or

against which the concrete is to be placed, shall be free from standing water, mud,

debris, organic deposits, and other foreign material which may prevent a tight bond

between the boulder bed and concrete. All surfaces of rock upon or against which the

concrete is to be placed shall, in addition to the foregoing requirements, be clean,

solid and free from oil, objectionable coatings, and loose, semi-detached, or unsound

fragments, and shall be sufficiently rough to assure satisfactory bond with the

concrete. The cleaning and roughening of the surfaces of rock/boulders shall be

performed by the use of high-velocity air-water jets, wet sand blasting, stiff brooms,

picks or other effective means satisfactory to the Employer. In the case of earth or

shale foundation, all soft or loose mud and surface debris shall be scrapped and

removed. The surfaces of absorptive foundations against which concrete is to be

placed shall be kept continuously wet for at least 24 hours immediately prior to placing

concrete so that moisture will not be drawn from the freshly placed concrete

6.1.3 Surfaces of Construction and Contraction Joints

Concrete surfaces upon or against which concrete is to be placed and to which

new concrete is to adhere, that have become so rigid that the new concrete cannot be

incorporated integrally with that previously placed, are defined as construction joints.

The surfaces of constructions joints shall be clean, rough and damp when

covered with fresh concrete or mortar. Cleaning shall consist of the removal of all

laitance, loose or defective concrete, coatings, sand, sealing compound if used, and

other foreign materials. Cleaning of the surfaces of construction joints shall be

accomplished by wet sand blasting, followed by thorough washing. The joints in mass

concrete, and where practicable in other concrete, shall be cleaned and washed

immediately before concrete in the next lift is placed. Where it is not practicable to

clean the joints after forms are set, the joints shall be wet sand-blasted and washed at

the last opportunity prior to setting the forms and the joints shall be washed thoroughly

with air water jets immediately prior to placement of the adjoining concrete. The

method to dispose off waste water used in curing and washing of concrete surfaces

shall be such that the waste water does not stain, discolour, or affect the exposed

surfaces of the structures. All embedded pipes, recesses or openings used for

43

disposing of waste water shall, after they have served their purpose, be filled

completely with concrete mixed in the proportions specified. All pools of water shall be

removed from the surfaces of construction joints before the new concrete is placed.

The surfaces of all contraction joints shall be cleaned thoroughly of accretions

of concrete or other foreign material by scrapping, chipping, or other satisfactory

means.

6.1.4 Placing Anchors in Concrete

Anchors bolts, structural shapes, plates and bearings required in connection

with the installation of gates, gate hoists, operating machinery, and other apparatus

shall be placed in concrete as found necessary. Wherever practicable, anchors shall

be installed before the concrete is place, and except as otherwise provided, drilling for

installation of anchors in concrete will not be permitted.

Where the installation of anchors prior to placing the concrete is not practicable,

satisfactory formed openings shall be provided and anchors shall be grouted into the

openings at some later time. Anchors bolts for machinery may be placed in approved

pipe sleeves to facilitate installation of machinery, and the sleeves shall be completely

filled with grout after the locations of the bolts are finally determined.

6.1.5 Chipping and Roughening of Concrete Surfaces

At places, as directed by the Employer, concrete surfaces upon or against

which additional concrete is to be placed shall be chipped and roughened to a depth

of not more than 25 mm of the surfaces.

The roughening shall be performed by chipping or other satisfactory methods

and in such a manner as not to loosen, crack, or shatter any part of the concrete

beyond the roughened surfaces. After being roughened, the surfaces of the concrete

shall be cleaned thoroughly of all loose fragments, dirt, lime, and other objectionable

materials and shall be sound and hard and in such condition as to assure good

mechanical bond between old and new concrete. All concrete which is not hard,

dense, and durable, shall be removed to the depth required to secure a satisfactory

surface.

44

6.2 Placing of Concrete

6.2.1 Transportation

The method and equipment used for transporting concrete and the time that

elapses during transportation shall be such as will not cause appreciable segregation

of coarse aggregates or slump loss in excess of 25 mm in concrete as it is delivered to

the work.

6.2.2 Placing

Concrete shall be placed only in the presence of a representative of the

Employer. After the surfaces have been cleaned and dampened as specified, all

approximately horizontal surfaces of work and unformed construction joints shall be

covered, wherever practicable, with a layer of mortar, not less than 12 mm and not

more than 20 mm thick. The mortar shall have the same proportions of water, air-

entraining agent, cement and sand as regular concrete mixture. The water-cement

ratio of the mortar in place shall not exceed that of concrete to be placed upon it, and

the consistency of the mortar shall be suitable for placing and working in the manner

here-in-after specified. The mortar shall be spread uniformly and shall be worked

thoroughly into all irregularities of the surface. Concrete shall be placed immediately

upon fresh mortar.

In formed work, structural concrete placements shall generally be started with

an over-sanded mix containing 20 mm maximum size aggregate, an extra 50 kg. sack

of cement per cubic meter and having 125 mm slump, placed several cm. deep on the

joint at the bottom of the form. Concrete placement shall commence immediately

thereafter.

Retempering of concrete shall not be permitted. Any concrete which has

become so stiff that proper placing without retempering cannot be assured shall be

wasted. Concrete shall be deposited in all cases as nearly as practicable directly in its

final position and shall not be caused to flow in a manner that the lateral movement

will permit or cause segregation of the coarse aggregate, mortar or water from the

concrete, caused by allowing the concrete to fall freely from too great a height or at

too great an angle from the vertical or to strike the forms or reinforcement steel, will

not be permitted and, where such separation would otherwise occur, suitable drop

chutes and baffles shall be provided to confine and control the falling concrete.

45

Methods and equipment employed in depositing concrete in forms shall be such as

will not result in clusters or groups of coarse aggregates particles being separated

from the concrete mass, but if clusters occur they shall be scattered before the

concrete is vibrated. A few scattered individual pieces of coarse aggregate that can be

restored into the mass by vibration will not be objectionable

6.2.3 Formed Concrete Placement

Except as intercepted by joints, all formed concrete, except concrete in tunnel

lining, shall be placed in continuous approximately horizontal layers. The depth of

layers for mass concrete to be placed in lifts of 150 cm or so and other concrete shall

be generally not exceed 50 cm. Lesser depths of layers will be placed where 50 cm

concrete layers cannot be placed in accordance with the requirements of these

Specifications.

To prevent feather edges, the construction joints at the tops of horizontal lifts

near sloping exposed concrete surfaces shall be inclined near the exposed surfaces

so that angle between such inclined surface and the exposed concrete surface will not

be less than 50o.

6.2.4 Unformed Concrete Placement

In placing unformed concrete on slopes so steep as to make internal vibration

of the concrete impracticable without forming, the concrete shall be placed ahead of

non-vibrated slip-form screed extending approximately 75 cm back from its leading

edge. Concrete ahead of the slip-form screed shall be consolidated by internal

vibrators so as to ensure complete filling under the slip form.

6.2.5 Mass Concrete

In placing mass concrete, the exposed area of fresh concrete shall be

maintained at the practical minimum, by first building up the concrete in successive

approximately horizontal layers up to the full width of the block and to full height of the

lift over a restricted area at the downstream end of the block and then continuing

upstream in similar progressive stage to the full area of the block. The slope formed by

the unconfined upstream edges of the successive layers of concrete shall be kept as

steep as practicable in order to keep its area minimum. Concrete along these edges

shall not be vibrated until adjacent concrete in the layer in placed, except that it

46

shall be vibrated immediately when weather conditions are such that the concrete will

harden to the extent that it is doubtful whether later vibration will fully consolidate and

integrate it with more recently placed adjacent concrete. Cluster of large aggregate

shall be scattered before new concrete is placed over them. Each deposit of concrete

shall be vibrated completely before another deposit of concrete is placed over it.

Mass concrete shall not be placed during rains sufficiently heavy or prolonged

to wash mortar from coarse aggregate on the forward slopes of the placement. Once

placement of mass concrete has commenced in a block, placement shall not be

interrupted by diverting the placing equipment to other places.

The concrete shall be deposited, as nearly as practicable in final position and

shall not be piled up in large masses at any point and then pushed, shovelled, or

vibrated into space for long distances. The full capacity of the bucket may be

deposited in one operation where this has no objectionable effect on the placing of the

concrete, but near forms, in and around embedded metal work, and elsewhere as

directed, the contents of the bucket shall be discharged in such quantities that

satisfactory placing will be secured.

Concrete buckets shall be capable of promptly discharging the low slump, mass

concrete mixes specified, and the dumping mechanism shall be designed to permit the

discharge of as little as 0.3 cubic meter portion of the lead in one place. Buckets shall

be suitable for attachment and drop chutes be used where required in confined

locations.

6.2.6 Placement of Monolithic Concrete

Where concrete is placed monolithically around openings having vertical

dimensions greater than 60 centimeters or where concrete in decks, floor slabs, top

slabs, beams, girders, or other similar parts of structures is placed monolithically with

supporting concrete, the following instructions shall be strictly observed.

1. Placing of concrete shall be delayed from 1 to 3 hours at the top of openings and

at the bottoms of bevels under decks, floor slabs, top slabs, beams, girders, or

other similar parts of structures when bevels are specified and at the bottom of

such structure members when bevels are not specified; but in no case shall the

placing be delayed so long that the vibrating unit will not readily penetrate of its

47

own weight the concrete placed before the delay. When consolidating concrete

placed after the delay, the vibrating unit shall penetrate and revibrate the concrete

placed before the delay.

2. The last 60 cm or more of concrete placed immediately before the delay shall be

placed with as low a slump as practicable and special care shall be exercised to

effect thorough consolidation of the concrete.

3. The surfaces of concrete where delays are made shall be clean and free from

loose and foreign material when concrete placing is started after the delay.

4. Concrete placed over openings and in decks, floors, beams, girders, and other

similar parts of structures shall be placed with as low a slump as practicable and

special care shall be exercised to effect thorough consolidation of the concrete..

6.2.7 Concrete Below Scroll Case

Concrete below scroll case shall be done by a series of 250 mm dia J-pipes.

250 mm dia M.S. J-pipes shall be manufactured in curvature and shape as per

direction of the Employer out of 20 gauge black sheets. J-pipes should be placed in

proper position and be held in position with the help of stays as directed by the

Employer. Precaution shall be taken to prevent displacements and choking of these

pipes during concreting around scroll case up to the time of concreting through these

pipes. The joints shall be welded as to conform to the applicable welding codes to the

satisfaction of the Employer.

6.2.8 Construction Joints

Constructions joints shall be approximately horizontal unless otherwise directed

by the chief engineer and shall be given the prescribed shape by the use of forms,

where required, or other means that will ensure suitable joining with subsequent work.

Unless otherwise directed, keyways will not be required at constructions joints.

Horizontal construction joints in mass concrete shall have a slope of approximately 15

mm from midway between sumps and from edges of the blocks to the sumps to

facilitate the removal of clean by waste. All construction joints intersecting with

concrete surfaces exposed to view shall be made straight and level or plumb.

48

6.2.9 Cold Joints

Cold joints shall be avoided where practicable. In the event of equipment break

down or for any other reasons, continuous placing is interrupted, the concrete shall be

thoroughly consolidated at such joints to a reasonably uniform and stable slope while

the concrete is plastic. If thorough consolidation at the sloping joints is not obtained

the Employer may require the use of bulk-headed construction joints. The concrete at

the surfaces of such cold joints shall be cleaned and damped as required for

construction joints before being covered with fresh mortar and concrete. The cleaning

of such joints shall consist of the removal of all loose and foreign material.

In mass concrete placement, delays may occur which result in cold joints within

a lift. When placement is resumed while the concrete is so green (and therefore,

capable of ready bonding) that it can readily be dug out with a hand pick, the usual

construction joint treatment will not be required if (1) the surfaces are kept moist, and

(2) the concrete placed against the surfaces is thoroughly and systematically vibrated

over the entire area adjacent to the older concrete. If the delay is short enough to

permit penetration of the vibrator into the lower layer during routine vibration of

successive layers, the vibrations will assure thorough consolidation. By eliminating

clean up and mortar coat, extra thorough vibration at such cold and semi-cold joints in

lieu of the usual mortar-joints treatment avoids interference with normal placing

operation and it saves cement.

6.2.10 Consolidation

Concrete shall be consolidated to the maximum practicable density, so that it is

free from pockets of coarse aggregate and entrapped air, and closes snugly against

all surfaces of forms and embedded materials. Consolidation of concrete in structures

and in tunnel lining inverts shall be by electric or pneumatic-drive, immersion-type

vibrators. Consolidations of concrete in the side walls and shall be by electric or

pneumatic-drive form vibrators, vibrators supplemented where practicable by

immersion-type vibrators. Vibrators having vibrating heads 10 cm or more in diameter

shall be operated at speeds of at least 6000 rpm when immersed in concrete.

Vibrators having vibrating heads less than 10 cm in diameter shall be operated at

speeds of at least 7000 rpm when immersed in concrete. Immersion-type vibrators

used in mass concrete shall be heavy duty, two-man vibrators capable of readily

49

consolidating mass concrete of the consistency specified. Form vibrators shall be

rigidly attached to the forms and shall be operate at speeds of at least 8000 rpm when

vibrating concrete.

In consolidation each layer of concrete, the vibrator shall be operated in a near

vertical position and the vibrating head shall be allowed to penetrate and revibrate the

concrete in the upper portion of underlying layers. In the areas where newly placed

concrete in each layer joins previously placed concrete, particularly in mass concrete,

more than usual vibration shall be performed, the vibrator penetrating deeply and at

close intervals into the upper portion of the previously placed layer along these

contacts. In all vibration of mass concrete, vibration shall continue until bubbles of

entrapped air have generally ceased to escape. Additional layers of concrete shall not

be superimposed on concrete previously placed until the previously placed concrete

has been vibrated thoroughly as specified. Care shall be exercised to avoid contact of

the vibrating head with surfaces of the forms.

Disturbances of the surface concrete at a construction joint during the early

stages of hardening shall be avoided. Necessary traffic on new concrete shall be on

timber walk-ways constructed so as to not cause injury to the concrete.

For formed concrete surface to be exposed to high velocities of water special

precautions shall be taken to prevent or to minimize surface pitting without resorting to

over manipulation of the concrete next to the forms. The use of mechanical vibrator

complying with IS: 2505-1992, IS 2506-1985, IS 2514-1963 and IS: 4656-1968 for

compacting concrete is recommended. Over vibration or vibration of very wet mixes is

harmful and should be avoided, under vibration is also harmful.

6.3 Placing Temperature

Concrete in all structures shall be placed at temperature between 10oC and

21oC. .

General Guidelines for various works:

1. Placement of concrete from April to September may be done normally

during the night hours only i.e. starting in the evening and ending by

morning.

50

2. To prevent shrinkage cracks, curing of freshly laid concrete may be

commenced promptly after placement and should remain uninterrupted

during the specified curing period.

3. During hot weather, the transit mixers shall be insulated and steel forms

shall be sprayed with direct river water.

6.4 Weather Conditions

Concrete operations shall be temporarily suspended during excessively hot or

rainy weather when conditions are such that the concrete cannot properly placed and

cured.

During hot weather no concrete shall be deposited when the temperature within

the forms is more than 50oC. Whenever necessary, exposed surfaces of fresh or

green concrete shall be shaded from the direct rays of the sun and protected against

premature setting or drying by being cured under continuous fine spray of water.

During continued rainy weather or heavy downpour, all freshly placed concrete

shall be covered and protected against surface wash. Special precautions shall be

taken to prevent the formation of lean seams or sand streaks. Mortar coats for

bonding construction joints shall not be placed or left exposed if the rain is tending to

increase the water-cement ratio of the mortar. Under no conditions shall concrete be

placed in a pool or a sheet of water. The top of all badly washed or streaked surfaces

shall be removed and washed before depositing the next course.

For other precautions / measures required to be taken for extreme weather

concreting reference may be made to Indian Standard Code of practice for extreme

weather concreting, IS:7861 (Part I) – 1975 “Recommended practice for hot weather

concreting” and IS:7861 (Part II) – 1981 “Recommended practice for cold weather

concreting.”

7. FINISHES AND FINISHING OF CONCRETE

7.1 General

Allowable deviations from plumb or level and from the alignment, profile grades

and dimensions, as specified in Section 4, are defined as “tolerances” and are to be

distinguished from irregularities in finish as described herein. The classes of finish

and the requirements for finishing of concrete surfaces shall be as specified in this

51

section or as directed. In the event that finishes are not definitely specified in this

section, the finish to be used shall be that specified for similar adjacent surfaces, as

determined by the Employer. Finishing of concrete surfaces shall be performed only

by skilled workmen and in the presence of a representative of the Employer.

Surface irregularities are classified as “abrupt” or “gradual”. Off-sets caused by

displaced or misplaced form sheathing or lining of form sections or by loose knots in

forms or otherwise defective form timber, will be considered as abrupt irregularities

and will be tested by direct measurements. All other irregularities will be considered as

gradual irregularities and will be tested by use of a template, consisting of a straight

edge or the equivalent thereof for curved surfaces. The length of the template will be

150 cm for testing of formed surfaces and 300 cm for testing of unformed surfaces.

All exposed surfaces, except where finish F1 is specified, shall be cleaned of

unsightly incrustations, oil drippings, rust stains and drainage from concrete work at

higher levels.

7.2 Finishes for Formed Surfaces

The classes of finish for formed concrete surfaces are designated by use of

symbols F1, F2, F3, F4 and F5. No sack-rubbing or sand-blasting will be done on

formed surfaces. Except as required for finishing of surfaces of spillways, stilling

basing etc., as set forth in definition of F4 given below, no grinding will be required on

formed surfaces, other than that necessary for repair of surface imperfections. Unless

otherwise specified, the classes of finish shall apply as follows:-

F1 - Finish F1 applies to formed surfaces upon or against which backfill or concrete is

to be placed or which will otherwise be permanently concealed. The surface

requires no treatment after form removal except removal and repair of defective

concrete and filling of holes left by the removal of fasteners from the ends of ties

rods, as required in section 8, and the specified curing. Correction of surfaces

irregularities will be required for depressions only, and only for those which, when

measured as described in para 7.1, exceed 25 mm. Form sheathing may be

anything that will not leak mortar where the concrete is vibrated. Forms may be

built with a minimum of refinement.

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F2 - Finish F2 applied to all formed surfaces not permanently concealed by backfill or

concrete, except surfaces for which finish F3, F4 or F5 is specified. Surfaces for

which finish F2 is specified will need no filling of pits or sack rubbing and no

grinding other than that needed for repair of surfaces imperfections. surfaces

irregularities, measured as described in paragraph 7.1, shall not exceed 6 mm for

abrupt irregularities and 12 mm for gradual irregularities. Where “no surfaces

irregularities” is specified, no abrupt irregularities will be permitted and gradual

irregularities shall not exceed 12 mm for the length of the surfaces designated.

The following surfaces generally receive F2 finish:-

a) Inspection galleries.

F3 - Finish F3 applies to formed surfaces, the appearance of which is considered to

be of special importance, such as surfaces of structures prominently exposed to

public inspection. No general stoning or grinding will be required on surfaces for

which finish F3 is specified, although in some cases, conspicuous air-holes shall

be filled by sack rubbing. Surface irregularities (measured as described in

paragraph 7.1) shall not exceed 3 mm for abrupt irregularities and 6 mm for

gradual irregularities, except that abrupt irregularities will not be permitted at

construction joints.

a) Exterior surfaces of buildings.

b) Decorative features on bridges.

c) Surfaces of structure permanently exposed to view.

d) Surfaces of access portals.

F4 - Finish F4 applies to formed surfaces for which accurate alignment and evenness

of surfaces are of paramount importance from the standpoint of eliminating

destructive effects of water actions. Abrupt irregularities shall not exceed 6 mm

for irregularities parallel to the direction of flow, 3 mm for irregularities not parallel

to the direction of flow. Gradual irregularities shall not exceed 5mm. Also, when

flow velocities exceed 12 meters per second, abrupt irregularities which are not

parallel to the direction of flow and off-set into the flow should be completely

eliminated by grinding on a 1 to 20 ratio of height to length.

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a) Streamlined surfaces of outlets, in-take structures, and transitions.

F5 - Finish F5 is required for forced concrete surfaces where plaster, stucco, or

wainscoting is to be applied. Since a coarse-textured surface is needed for bond,

the concrete should be cast against rough faced form boards. Form oil should not

be used. Steel lining or steel sheathing is not permitted.

7.3 Finishes for Unformed Surfaces

The classes of finish for unformed concrete surfaces are designated by the

symbols U1, U2, U3, U4 and U5. Interior surfaces shall be sloped for drainage where

directed. Surfaces which will be exposed to the weather and which would normally be

level, shall be sloped for drainage. Unless the use of other slopes or level surfaces is

directed, narrow surfaces, such as tops of walls and curbs, shall be sloped

approximately 10 mm per 30 cm of width: broader surfaces such as walks, roadways

platforms, and decks shall be sloped approximately 5 mm per 25 cm. Unless

otherwise specified, these classes of finish shall apply as follows:-

U1- Finish U1 (screeded finish) applies to unformed surfaces that will be covered by

backfill or by concrete; surfaces of bridges pavements; and surfaces of sub-floors

which will be covered by concrete floor topping. Finish U1 is also used as the first

stage of finishes U2 and U3. Finishing operations shall consist of sufficient

levelling and screeding to produce even uniform surfaces. Surfaces irregularities,

measured as described in para 7.1, shall not exceed 9 mm.

U2 - Finish U2 (floated finish) applies to unformed surfaces not permanently

concealed by backfill or concrete or for which finish U3 is not specified. Finish U2

is also used as the second stage of finish U3. Stair treads after floating shall be

roughened by brooming parallel to the long dimensions of the tread. The

concrete shall then be tooled round. Floating shall be performed by use of hand

or power-driven equipment. Floating shall be started as soon as screeded

surfaces has stiffened sufficiently, and shall be the minimum necessary to

produce a surfaces that is free from screed marks and is uniform in texture. If

finish U3 is to be applied, floating shall be continued until a small amount of

mortar without excess water is brought to the surfaces, so as to permit effective

trowelling. Surfaces irregularities measured as described in para 7.1, shall not

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exceed 6 mm. Joints and edges of gutters, side walls and entrance slabs and

also other joints and edges shall be tooled when so directed.

Surfaces to receive U2 finish include:-

a) Surfaces of inverts of siphons, aqueducts, Flumes.

b) Floors of canal structures.

c) Bridge floors and bridge deck.

d) Floors of galleries, sumps, culverts, adits and chambers.

e) Tops of piers & walls, except tops of parapet walls prominently exposed

to view.

f) Surfaces of gutters, side walls, stairs, and outside entrance slabs.

g) Slabs that will be covered with built-up roofing or membrane water

proofing.

h) Surfaces of safety rack structures and transitions.

U3 - Finish U3 is a trowelled finish. When the floated surface has hardened

sufficiently to prevent excess of fine material from being drawn to the surface,

steel trowelling shall be started. Steel trowelling shall be performed with firm

pressure, such as will flatten the sundry texture of the floated surfaces and

produce a dense uniform surface, free from blemishes and trowel marks; except

that light steel trowelling will be permitted on surfaces of slabs to be covered with

built-up roofing or membrane water proofing, in which event light trowel marks

will not be considered objectionable; surface irregularities, measured as

described in para 7.1, shall not exceed 6 mm. All abrupt irregularities, offsets and

bulges shall be ground to a slope not steeper than 1 in 20, provided that any

abrupt irregularities not parallel to the flow such as those at transverse joints

shall be to a slope not steeper than 1 in 40.

Finish U3 applies to the following surfaces:-

a) Tops of parapet walls prominently exposed to view.

b) Interior stair treads and thresholds.

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c) Floors of transitions upstream and downstream of gate shaft.

d) Floor of the outlets works downstream from the gate frames.

U4 - The finished surfaces should be equivalent in evenness, smoothness, and

freedom from rock pockets and surfaces voids, to that obtainable by effective use

of a long handled steel trowel. Light surface pitting and light trowel marks are not

objectionable. Where the surface produced by a lining machine meets the

specified requirements, no further finishing is necessary. If a few spots are left by

the lining machine, there is no objection to the immediate use of a little mortar to

reduce the labour of producing an acceptable finish. Surfaces to receive F4 finish

include:-

a) Canal and lateral linings.

U5 - Finish U5 includes various special finishes requiring certain finishing procedures

in each case. It is also used for architectural purposes.

7.4 Maximum Allowance of Irregularities

Max. allowance of irregularities in concrete surfaces as given in preceding

paragraphs of this section are tabulated below:-

Finish (formed surfaces) Finish (unformed surfaces)

Type of Irregularities

F1 F2 F3 F4 F5 U1 U2 U3 U4

mm mm mm mm mm mm mm mm mm

Depressions 25 -- -- -- -- -- -- -- --

Gradual -- 10 5 5 5 -- -- -- --

Abrupt -- 5 3 5* 5 -- -- -- --

All Surfaces -- -- -- 3** -- 9 5 5 --

Canal surfaces Bottom -- -- -- -- -- -- -- -- 5 slab

Canal surfaces Side -- -- -- -- -- -- -- -- 10 slopes

* Allowance of irregularities or off-set extending parallel to flow.

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** Allowance of irregularities or off-set not extending parallel to flow.

1. Allowance in mm measured from 1525 mm template.

2. Allowance in mm measured from 3050 mm template.

7.5 Finishing recesses

All recesses in concrete, where required for lightening units, lightening panel

boards, miscellaneous power boards, and all other recesses for installing equipment

shall be thoroughly cleaned and washed, and given one brush coat of neat white

Portland cement prepared by thoroughly mixing sufficient white Portland cement with

water to produce a consistency equivalent to that of thick cream. The cement shall be

applied while the surface is still moist. After the cement has set and has become

reasonably dry, the recess shall be painted with two coats of white vinolite paint.

8. PROTECTION, CURING & REPAIR OF

CONCRETE 8.1 Protection of Concrete

All concrete shall be adequately protected from mechanical injury. Unhardened

concrete shall be protected from heavy rains and flowing water. No fire or excessive

heat shall be permitted near or in direct contact with concrete at any time. All galleries

and conduits etc. shall be bulk headed during construction period to prevent free

circulation of air and resultant drying of concrete. Exposed finished surfaces of all

concrete shall be protected from the direct rays of the sun for at least the first three

days after placement. Such protection shall be made effective as soon as practicable

after the placing of unformed concrete or after the removal of forms from formed

concrete.

8.2 Curing of Concrete

Concrete shall be cured either by water (water curing) or by the use of sealing

compounds (membrane curing).

8.2.1 Water Curing

Concrete cured with water shall be kept wet for at least 14 days for ordinary

Portland cement concrete and 21 days for low heat or pozzolana mixed cement

concrete after placement of concrete. Curing shall start as soon as the concrete has

hardened sufficiently to prevent damage by moistening the surface and shall continue

until completion of the specified curing period or until covered with fresh concrete. The

concrete shall be kept wet by covering the unformed surface with water-saturated

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material (such as damp sand, or by use of wet sacks) or by a system of perforated

pipes, mechanical sprinkler, or porous hose, or by any other approved method which

shall keep all surfaces of concrete continuously wet. Appropriate measures shall be

adopted to protect exposed surfaces of fresh concrete from water spray.

All equipment needed for adequate protection and curing of the concrete shall

be on hand and ready to install before actual concrete placement begins. Detailed

plans, provisions and procedures whereby the various protection and curing phases

will be firmly established, and shall be settled prior to the initial stages of concreting

operations.

Water for curing shall be clean and free from any element which will cause

staining or discolouration of concrete besides meeting the specifications for water

used for mixing concrete.

Where forms of lagging are used and left in place during curing, the lagging

shall be kept wet at all times to prevent the lagging from opening at the joints. Forms

in tight contact with new concrete shall also be kept wet so as to keep the surface of

new concrete as cool as possible.

Construction joints shall be cured in the same manner as other concrete

surfaces & shall be kept moist for at least 72 hours prior to the placing of additional

concrete upon the joints.

8.2.2 Membrane Curing

Membrane curing shall be application of a sealing compound which forms a

water retaining membrane on the surface of the concrete. The sealing compound shall

be white- pigmented and shall conform to U.S.B.R. “Specifications for Sealing

Compound for Curing Concrete” June 1, 1961 or its equivalent. The compound shall

be of uniform consistency and quality within each container and from procurement to

procurement.

Sealing compound shall be applied to the concrete surfaces by spraying in one

coat to provide a continuous, uniform membrane over all areas. Coverage shall not

exceed 3.5 sq. meters per litre and on rough surfaces coverage shall be decreased as

necessary to obtain the required continuous membrane. Mortar encrustations and fins

on surfaces designated to receive finish F3 or F4 or F5 shall be removed prior to

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application of sealing compound. The repair of all other surface imperfections shall not

be made until after application of sealing compound.

When sealing compound is used on unformed concrete, surface application of

the compound shall commence immediately after the finishing operations are

completed. When sealing compound is to be used on formed concrete surfaces, the

surfaces shall be moistened with a light spray of water immediately after the forms are

removed and shall be kept wet until the surfaces will not absorb more moisture. As

soon as the surface film of moisture disappears but while the surface still has a damp

appearance, the sealing compound shall be applied. Special care shall be taken to

ensure ample coverage with the compound at edges, corners and rough spots of

formed surfaces. After application of the sealing compound has been completed and

the coating is dry to tough, any required repair of concrete surfaces shall be

performed. Each repair, after being finished, shall be moistened and coated with

sealing compound in accordance with the foregoing requirements.

Equipment for applying sealing compound and the method of application shall

be in accordance with the provision of the U.S.B.R. “Concrete Manual” or its

equivalent and other operations shall be such as to avoid damage to coatings of

sealing compound for a period of not less than 28 days. Where it is impossible

because of construction operations to avoid traffic over surfaces coated with sealing

compound, the membrane shall be protected by covering of sand or earth not less

than 25 mm in thickness or by other effective means. The protective covering shall not

be placed until the sealing membrane is completely dry. Before final acceptance of the

work, all sand or earth covering shall be finally removed in an approved manner. Any

sealing membrane that is damaged or that peels from concrete surfaces within 28

days after application shall be repaired without delay and in an approved manner.

Sealing compound shall be tested before use after obtaining proper samples.

Sampling will be in accordance with Designation 38 of the U.S.B.R. “Concrete

Manual” or its equivalent.

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8.3 Repair of Concrete

Repair of concrete shall be performed by skilled workmen and in the presence

of a representative of the Employer. All imperfections of concrete surfaces shall be

corrected as necessary to produce surfaces that conform to the requirements

specified in Section 7. Repair of imperfection in formed concrete shall be completed

within 24 hours after removal from surfaces for which finishes F2, F3, F4 and F5 are

specified and encrustations shall be removed from surfaces for which finishes U2, U3,

U4, U5 are required. Concrete that is damaged from any cause and concrete that is

honeycombed, fractured, or otherwise defective and concrete which, because of

excessive surface depression must be excavated and built up to bring the surface to

the prescribed lines, shall be removed and replaced with dry-pack mortar or concrete,

as here-in-after specified (see paragraph 8.4 for dry-pack and refer to U.S.B.R.

“Concrete Manual” for mortar filling and concrete filling procedures). If removal of the

ends of form ties results in recesses larger than 6 mm in diameter or in the minimum

dimension, the recesses shall be filled with dry-pack except that filling of recesses in

surfaces designated to receive finish F1 will be required only where the surfaces are

required to be coated with damp proofing, and where the recesses are deeper than 25

mm in walls less than 30 mm thick.

Where bulges and abrupt irregularities protrude outside the limits specified in

Section 7 on formed surfaces for which finishes F2, F3, F4 are required, the

protrusions shall be reduced by bush-hammering and grinding so that the surfaces are

within the specified limits. Off-sets and other abrupt irregularities, on surfaces for

which finish F4 or F5 is required which exceed the limits specified in Sections 7, shall

except for F4 or other surfaces requiring reduction or elimination of irregularities by

grinding be dressed smoothly to bevels having cross-sectional length not less than 6

times the amount of projection. After dressing, the irregularities shall not exceed the

limits specified in Section 7. Off-sets and other irregularities, on F4 or other surfaces

requiring reduction or elimination of irregularities by grinding, shall be reduced or

eliminated in accordance with the finishing requirements.

Dry pack filling (see paragraph 8.4) shall be used for filling holes having at

least one surfaces dimension little, if any, greater than the holes depth, for narrow

slots cut for repair of cracks, for grout and cooling pipe recesses and for tie rod

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fastener recesses as specified. Filling of holes left by the removal of fasteners from

the ends of the tie rods in surfaces for which finish F1 is specified will not be required.

Dry pack shall not be used for filling behind reinforcement or for filling holes that

extend completely through concrete section.

Mortar filling, placed under impact by use of mortar gun, may be used for

repairing defects on surfaces designated to receive F1 and F2 finishes where the

defects are too wide for dry pack filling and too shallow for concrete filling and no

deeper than the far side of the reinforcement that is nearest the surface.

Concrete filling shall be used for holes extending entirely through concrete

section for holes in which no reinforcement is encountered and which are greater in

area than 930 sq. cm and deeper than 10 mm and for holes in reinforced concrete

which are greater in area than 465 sq. cm. and which extent beyond reinforcement

and for holes resulting from drilling of 25 cm diameter concrete test cores as provided

in Section 3.

All materials used in the repair of concrete shall conform to the requirement of

these specifications and repairs shall be in accordance with procedures of chapter VII

of the U.S.B.R. “Concrete Manual” or equivalent. All fillings shall be bonded tightly to

the surfaces of the holes and shall be sound and free from shrinkage cracks and

drummy areas after the fillings have been cured and have dried. All fillings in surfaces

for which finish F3 is specified shall contain sufficient white Portland cement to

produce the same colour as that of the adjoining concrete.

All patching shall be done with extreme care, so that patches will not be

noticeable from a distance of 25 meters. Colour cement as an ingredient of the

patching mortar may be used, if necessary, to produce patch of same colour as the

adjoining concrete.

8.4 Dry Pack Mortar

Repair operations shall be proceeded by a careful inspection to see that the

hole is thoroughly clean and slightly wet but with a small amount of free water on the

interior surface. The surface shall then be dusted lightly and slowly with cement by

means of a small dry brush until all surfaces have been covered and darkened by

absorption of the free water by the cement. There shall be no dry cement in the holes

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when packing begins and such cement if present shall be removed. The holes shall

not be painted with neat cement grout.

Dry pack mortar shall consist of a mixture of 1 part of cement to 2.5 parts of

sands that will pass a No. 16 ASTM Screen (IS Sieve No. 120). White cement will be

used in sufficient quantity to produce uniform colour matching with that of the

surrounding concrete at points wherever desired by the Employer.

For packing cone-bolt holes, a leaner mixture of 1:3 or 1:3.5 will be used. Only

enough water shall be used to produce a mortar which when used, will stick together

on being moulded into a ball by a slight pressure of the hands and will not exude water

but shall leave the hands damp. The proper amount of mixing water and the proper

consistency are those which will produce a filling which is at a point of becoming

rubbery when the material is solidly packed.

Dry pack mortar shall be placed and packed in layers having a compacted

thickness of about 10 mm. The surface of each layer shall be scratched to facilitate

bonding with the next layer. One layer may follow another immediately unless

appreciable rubberiness develops, in which case work on the repair shall be delayed

by 30 to 40 minutes. Under no circumstances shall alternate layers of wet and dry

materials be used.

Each layers must be solidly compacted over its entire surface by use of hard-

wood stick and hammer. These sticks are usually 20 to 30 cm long and not over 25

mm in diameter and are used on the fresh mortar like a caulking tool. Much of the

tamping will be directed at a slight angle and towards the sides of the hole to assure

maximum compaction in these areas. The holes shall not be over filled and finishing

shall be completed at once by laying the flat side of a hardwood piece against the fill

and striking it several good blows. Steel finishing tools shall not be used and water

must not be used to facilitate finishing.

8.5 Expansive Concrete or Mortar

In place where tight fillings are required such as back filling of block outs and

repair works in spillway stilling basin, a special expansive concrete or mortar is used

instead of ordinary dry pack mortar or concrete described above. This concrete has an

admixture of a very small quantity of aluminium powder that largely reduces

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separation of water (bleeding) which would cause “settlement shrinkages” and also

cause expansion of concrete or mortar, thus filling up the confined space fully.

The aluminium powder, which should be of the unpolished variety, shall be free

from impurities and it shall have a fineness such that 100% of this passes through IS

Sieve 75 micron. The powder shall be first be blended with 50 parts by weight of some

inert pulverized material such as calcined shale. The blend shall then be added to the

concrete by sprinkling over the batch. The amount of blend to be used shall be

determined by laboratory tests. Aluminium powder shall not be used until test with job

material and at job temperatures have shown that effective expansion can be obtained

can be obtained and even then only under strict control.

The blend shall be mixed thoroughly with cement and sand before water is

added, otherwise the aluminium powder will float on water. Batches shall be small

enough to allow placement of freshly prepared mortar, as the action of the aluminium

becomes very weak about 45 minutes after mixing. After all ingredients are added, the

batch shall be mixed for 3 minutes.

The cavity in which concrete is to be filled should be confined by suitable form

work on all sides to take proper advantages of this expansive concrete.

9. STEEL REINFORCEMENT

9.1 Scope

The specification covers the item of providing, fabricating and placing in

position reinforcement bars for RCC works, anchor rods etc., including cost of steel,

binding wire, cleaning, cutting, bending, tying, welding wherever directed, lapping,

providing necessary protective works to keep the working area dry, desilting etc.,

complete with all leads and lifts.

9.2 Applicable Publications

The steel for reinforcement bars and all methods and procedures for fabrication

and placing in position of reinforcement bars for RCC works shall conform to following

latest revisions of IS specifications or other Internationally recognized standard

specifications:

IS: 456 Code of practice for plain and reinforced concrete.

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IS: 1786 High strength deformed steel bars and wires for concrete

reinforcement.

IS: 2502 Code of practice for bending and fixing of bars for concrete

reinforcement.

9.3 Materials

The reinforcement steel shall be high-yield strength deformed bars of grade Fe-

500/550 conforming to latest revision of IS: 1786. All reinforcement steel required for

the work shall be procured by the Contractor from reputed manufacturer like SAIL,

TISCO, RASHTRIYA ISPAT NIGAM LTD., JSPL in standard lengths. The binding

wire for tying the reinforcement bars in position shall be 1.25 mm dia soft annealed

steel wire having yield point strength not less than 350 MPA.

9.4 Fabrication

Reinforcement bars shall not be straightened or bent in a manner that will injure

or weaken the material. Bars shall be bent cold to the shape and dimensions as per

design or as directed, using a bar bender operated by hand or power to attain the

proper shape. The radius of any bend shall not be less than 4 times the diameter of

the bar. Heating of reinforcement bars to facilitate bending shall not be permitted. The

reinforcement bars available from rejected work shall not be used. After fabrication,

the bars of same size, diameter and shape shall be grouped separately and stored in

racks duly marking the identification details for early identification during placing.

9.5 Placing in Position

All fabricated reinforcement bars shall be cleaned of rust, scale, dirt, grease or

other objectionable substances before use. Before the reinforcement bars are fixed in

position, it shall be verified that these are of the specified diameter and are cut and

bent in accordance with design. These shall be accurately placed and secured in

position by means of built in concrete blocks, steel chairs, hangers, spacers or other

suitable devices at sufficiently close intervals so that they will not sag either between

supports or be displaced during the placing of the concrete or by any operation of the

work. Cement mortar cover blocks of requisite size shall be used to maintain cover at

all places. The spacers and cover blocks shall be secured to reinforcements so that

these shall not be displaced during tamping or vibrating. No timber pieces, stone chips

or any other soft materials, to be used as cover blocks, shall be permitted.

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The reinforcement bars shall have concrete covers as specified. Special care

shall be exercised to prevent any disturbance of reinforcement bars in concrete that

has already been placed. The reinforcement bars after being placed in position shall

be maintained in clean condition until it is completely embedded in concrete. Steel

reinforcement bars shall be placed in the concrete as directed. Where the exact

positions, size and shapes of reinforcement bars are not shown, detailed bar-lists and

bending diagram will be prepared and furnished by the Employer. The longitudinal

bars shall be straight and fixed parallel to one another and to the side of the forms or

as directed.

The ties, links and stirrups connected to the bars shall be tightly drawn so that

the bars are properly braced. The ties, links and stirrups shall be in actual contact with

the bars around which they are placed and their position shall be exactly as specified

in the design or as directed. Bar splices shall be used as per design unless the

Employer therein approves modifications. Splicing at points of maximum stress shall

be avoided. Splicing of adjacent bars at one position in plan shall be avoided as far as

possible. All protruding bars from concrete to which bars are to be spliced later shall

be protected from rusting by a thin coat of neat cement grout. Accurate records shall

be kept at all times of the number, size, length and weight of bars placed in position

for different parts of the work. All joints shall be lap joints, lap being as directed. Where

lap joints are provided in the reinforcing bars they shall be staggered and in conformity

with the requirements laid down in the latest revision of IS: 456. In exceptional cases,

welding of reinforcement rods shall be done wherever required as directed by the

Employer. No extra payment will be made on this account.

Welding of joints may be allowed in place of lapping at the direction of the

Employer. The joints shall be butt-welded and shall be of the V-cut type. Welding shall

be done by the electric arc method. The ends of the bars shall be cleaned of all loose

scales; rust, grease or other foreign materials and all welding shall conform to the best

modern practice. The reinforcement placed in position shall be got approved by the

Employer before embedding the same in concrete.

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2. Specifications for Items Other than RCC

10. FOUNDATION EXCAVATION

10.1 Scope

These specifications shall govern the general requirements for all excavation

work relating to the foundations work. In case of doubt in the interpretation of these

specifications, the Employer or any other officer deputed on his behalf shall exercise

his discretion.

10.2 Setting Out

Reference burjis on definite station and chain lines shall be established at a

safe distance away from the top cut limits and their levels determined accurately with

reference to permanent Bench Marks.

Concrete pillars should be fixed along the proposed top of cut of the pit to be

excavated with correct ground levels marked on them with reference to permanent

Bench Marks to control excavation. All levels shall be with reference to established

bench marks not subject to subsidence or interference.

10.3 Clearing

The pit and surrounding area as required for excavation operations shall be

cleared of all trees, bushes, rubbish and other objectionable matter. Similar clearance

shall be done in areas earmarked for storing selected excavated materials for reuse

on the project. The cleared material shall be suitably disposed off by removal from the

site so as not to interfere with construction operations and maintenance of works. In

the work of disposal, all necessary precautions shall be taken for the protection of

persons, works and private property. Non-cohesive or any other excavated material

proposed to be used in the backfill around Aqueduct*- or for any other purpose shall

stacked separately as directed by the Employer.

10.4 Stripping

Before excavation work is taken up, all loose material close to the area to be

excavated which is liable to fall or otherwise endanger workmen or works, shall be

stripped. The method used shall be such as not to shatter or render unsuitable or

unsafe any formation which is originally sound.

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10.5 Access and Haulage Roads

Access and haulage roads shall be constructed as and when required to

facilitate economical excavation operations and disposal of excavated material and

keeping in view the safety of adjoining structures, slopes, men, material and

equipments etc. The alignment and layout of these will be subject to approval of the

Employer to ensure that these do not interfere with permanent excavation lines,

slopes or foundations of appurtenant works.

10.6 Excavation – Basic Requirements

Excavation shall be done according to the approved drawings or direction of the

Employer. Excavation of the pit shall be done to the level as shown in the approved

drawings except that a depth of 1 meter + above the foundation level shall be kept

unexcavated. Excavation to the final foundation level shall be done after the relevant

tests are completed and just before the foundation is required for laying grounding

mat, concrete, etc. so as to avoid any deterioration of the foundation.

The bottom 1 m layer above the foundation level shall be excavated carefully at

the time of preparation of subgrade or placement of concrete in the raft so as not to

over-excavate, disturb or loosen the natural sub-grade in any manner. Over

excavation shall be avoided. In unavoidable circumstances, any excess excavation

under concrete raft of Aqueduct shall be filled up satisfactorily with lean concrete or

compacted back fill with prior approval of the Employer.

All excavation shall be done to the slopes, lines and grades as indicated on the

approved drawings except where, during the progress of work, it is felt necessary to

modify the slopes and or provide benches to ensure stability of the slopes. Any

deviation from approved drawings shall be done in consultation with the Employer.

A careful watch for the stability of slopes shall be kept during construction stage

and suitable measures shall be taken immediately if any movement is noticed before

proceeding with further excavation.

Effective dewatering arrangements shall be made to ensure that no boiling take

place at the bottom of the pit and that no sloughing/cavities on the excavated slopes

occur. To prevent blow out of the bed of the pit at all levels suitable arrangement shall

be made to observe artesian pressure so that the same, if found to be excessive, is

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reduced by pumping before proceeding further with excavation of the pit. The pumped

water shall be discharged at a sufficient distance from the pit so that it flows away and

does not find its way back to the pit.

The pit material considered suitable for backfill of the pit, filling reaches of the

Hydel Channel, and which may be required to be so used shall be excavated in a

manner so as not to mix it with other materials and stock piled separately at proper

sites as directed by the Employer.

Disintegrated or loose and weathered material resulting from exposure or due

to any other reason shall be removed. The final clean up shall be done to the

satisfaction of the officer designated as Inspector prior to the placement of concrete or

backfill.

10.7 Method of Excavation

Excavation shall be done by standard excavation equipments such as rippers,

power shavers, bulldozers and by such techniques as conform to the best current

practice for such works and as required to reduce to the minimum any excavation and

not to cause injury to the foundation beyond the specified lines of excavation.

10.8 Disposal of Excavated Material

Excavated materials suitable for being used in the backfill or for any other

purpose on the project shall be carefully stock piled at suitable places designated for

the purpose or carried direct to the sites where required. Other material shall be

disposed off at placed earmarked for the purpose of disposal and as directed by the

Employer.

10.9 Dewatering

Where the foundation excavation extends below the water table, dewatering

arrangement shall be made in advance of excavation. The dewatering shall be

accomplished in a manner that would prevent the loss of fines from the foundation,

maintain stability of excavated slopes etc. and ensure all construction operations

being performed in dry conditions. Suitable methods shall be used for dewatering as

approved by the Employer.

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11. BACKFILL

11.1 Scope

These specifications shall govern the general requirements for compaction of

backfill around structures to be constructed. Backfilling constitutes procuring of

suitable materials, depositing in the defined and approved areas and compacting to

the required specified density as specified by the Employer.

11.2 Location of Backfill & Production of Fill Material

When sufficient and suitable materials for the backfill are not available from the

Aqueduct excavation, the material shall be procured from approved resources as per

para 2.4 of the Specifications.

All borrow areas shall be stripped of top soil, loam, vegetation and other

materials which are unsuitable for filling, and the same shall be disposed off

separately as approved by the Employer. The approved backfill material, if stockpiled,

shall be maintained free of vegetation.

11.3 Preparation of Foundation Surface and Placement

Before the backfill is placed, the areas shall be cleared of all rubbish such as

bushes, grass, pieces of wood, steel, slush and other objectionable material. The

material so removed shall be burnt or otherwise disposed off or removed to a safe

distance so that, it may not interfere or mix with the earthwork to be carried out.

Backfill shall not be placed on any part of the foundation surface unless that part has

been inspected and approved. No slopes against which the fill is placed shall be

steeper than 1:1. In case steeper slopes are encountered they should be either

flattened or the area close to the slope shall be compacted to the desired density by

hand operated or other suitable equipment.

The fill shall be free from lenses, pockets or layers of material differing

substantially, in texture or gradation unless specified in Drawings. The combined

dumping, spreading and compacting operations shall be such that the materials will be

blended sufficiently so as to avoid rock pockets and to secure the degree of

compaction as specified.

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11.4 Gradation Requirements

Cohesionless reasonably well graded pervious sand gravel material shall be

placed in the backfill. „Reasonably well graded‟ means that there should be a

reasonably good distribution of all sizes of particles from the coarsest to the finest and

without a major deficiency of any size or group of sizes. The distribution of material

must be uniform and such that compacted back-fill is free from lenses, pockets,

streaks or other imperfections. The gradation curves of the material to be used as

back-fill, shall be got approved from the Employer before using it.

11.5 Compaction

The compaction shall be done in layers. The depth of layer after compaction

unless otherwise specified, should not be more than 300 mm maximum, when tractors

or surface vibrators are used or a depth equal to the penetration length of the internal

vibrators. The layer under compaction shall be thoroughly wetted during compaction.

Proper precautions shall be taken to avoid damage to power plant building and other

structures. To achieve this, hand-operated pneumatic tools shall be used in the vicinity

of the structure, where the depth of the layer after compaction shall not exceed 100

mm. Rock pockets shall not be permitted any-where. The zone under the service bay

and ducts shall be compacted to 85% relative density. The rest of the backfill shall be

compacted to 60% relative density.

The adequacy of compaction and moisture control of pervious soils shall be

controlled by field density tests in conjunction with the relative density tests as outlined

in relevant IS 2720-1968 code. As the adequacy of compaction is specified in terms of

density achieved, the Employer can seek sufficient number of tests. At the start of

work a number of tests are required to specify the compaction operations to produce

the desired results, after this has been established, the number of tests required are

only those necessary to ensure that the specifications requirements are met with.

Minimum one test for each 150 cubic meters (200 cubic yards) shall be done in this

zone. For the rest of the backfill portion, it is expected that the required relative density

would be achieved by spreading the material in layers of specified thickness, flooding

and normal movement of the dumping equipment. This may, however, be occasionally

checked by field density tests to see that the required density is achieved.

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The top surface of backfill shall be finally finished as per lines and grades to be

specified by the officer designated as Inspector. The low spots shall be filled up and

dressed up to the specified lines and grades after the backfill has withstood one rainy

season.

11.6 Sub-Soil Water Level

While compacting, the sub-soil water level in the fill should be maintained at

least 300 mm lower than the bottom of the layer being compacted.

12. Water Proofing Seals and Joints

12.1 Contraction Joints

Concreting shall be done on one side of the joint first. The form is removed

from the joint face and then a coat of sealing compound conforming to IS: 1834-1984

“Specifications for hot applied sealing compounds for joints in concrete”, shall be

applied to prevent adhesion of concrete to be placed against the formed face. The

reinforcement is discontinued and bond not allowed to develop between the joints

faces thereby introducing structural discontinuity. Contraction joints may be provided

between each block of one unit. These joints shall be effectively water sealed so that

the rain water is not allowed to seep through them.

12.2 Expansion Joints

Expansion joint is made by placing fresh concrete after separating the old

surface by joint filler. In order to provide an expansion joint 25 mm space shall be left

between the concrete joint faces to permit expansion and allow room for joint filling

between seals.

Preformed Joint Filler

25 mm or less thick preformed joint filler shall be placed as directed.

Materials

1) Preformed joint filler conforming to IS:1838 (Pt I)1983 “Specification for preformed

fillers for expansion joints in concrete non-extending and Resilient type (Bitumen

impregnated fiber).”

2) Vinyl resin paint – vinyl resin paint shall be in accordance with clause 7.3 of IS:

4461-1998.

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3) Joint compound shall conform to IS 1834-1961, “Specification for hot applied

sealing compound for joints in concrete.”

Field Coating

All surfaces of the preformed joint filler shall be coated with vinyl resin paint or

bitumen. The surface or the preformed joint filler to be coated shall be clean and dry

and shall be free from loose, hanging particles. Each coat of Vinyl-resin paint shall be

applied at the rate of 1 Litre for each 50 sq. meter area and allowed to dry thoroughly

before the following coat is applied or before the joint filler is placed against the

completed side of the expansion joint. After the coated joint filler has been cut to

shape, all out edges of the coated joint filler shall be given two coats of Vinyl – resin

paint or bitumen.

Installation

The preformed joint filler shall be cut to cover the entire surface of the concrete

at the joints around which preformed joint filler is required to be placed except where

directed, the exposed edges of the filler materials shall be placed at a prescribed

distance back from the finished surfaces of the concrete. Where placed against

vertical concrete surfaces, the joint filler shall be held securely in place against the

completed side of an expansion joint by nails pre-cast in the first placed concrete. All

joints in the filler material shall be so water tight as not to permit any mortar from the

concrete to seep through to the opposite concrete or metal surface.

12.3 Asphalt Seals

The asphalt seals 140 mm x 140 mm, where directed by the Employer, shall be

provided in the Power House. Expansion joints are made water tight by use of rubber

water stops and asphalt seals. The water-stops are installed, one on each side of

diamond shaped hole which filled with asphalt as on additional seal against possible

leaks in the water-stops.

All materials for asphalt seals including metal cover plates and frames for

recesses, 18 mm electrodes fastening bars, clamps and wire for supporting electrodes

and asphalt material shall conform to the applicable IS Codes. The electrodes shall be

secured rigidly at different points and all electrode connections shall be made tight and

leak proof. After each lift of concrete has been completed, the recesses for the

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seals shall be filled with hot asphalt during construction to ensure dense filling.

Heating shall be accomplished electrically through electrodes which shall be left in

place and be used for reheating if leak develops at a later stage. After each seal has

been completed to the top, the seal shall be capped.

The bidder when directed, shall connect the electrodes in the seal to the power

and electric current shall be passed through the electrodes until all the asphalt in the

seal is liquefied completely. The bidder shall make arrangements to avoid any leakage

of current.

Rubber Water Stops

The rubber water stops shall be fabricated and cured in such a manner that any

cross-section will be dense, homogeneous and free from porosity and other

imperfections.

The following minor surface defects will be acceptable

- Lumps and depressions not exceeding 0.64 cm in longest lateral

dimensions and 0.16 cm deep with no limit to the frequency of occurrence

- Lumps and depressions between 0.64 and 1.27 cm in longest lateral

dimension and 0.24 cm deep as long as the frequency of occurrence does

not exceed six in a 15.0 m length, and there are at least 5 cm between any

two such defects.

- Marks resulting from the tubing operation or handling during manufacturer,

with no limit to width or frequency of occurrence, as long as the thickness of

material below the mark is not less than the minimum thickness.

- Coarse or grainy surface texture.

- Suck-back along flash lines of molded goods, if not more than 0.16 cm wide,

0.16 cm deep, and not more than 0.60 cm long.

Any defects which are not within the above limitations shall either be repaired

as approved by the Employer or be removed by cutting out such defects and splicing

the water stop at that point. All factory splices shall be molded splices. All molded

splices shall withstand being bent 1800 around a 5 cm diameter pin without any

separation at the splice.

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Rubber for the water stop shall be high-grade, tread-type compound. The basic

polymer shall be natural rubber, synthetic rubber or a blend of both. The rubber, when

tested in accordance with the relevant standards shall have the physical properties

mentioned under these standards. Gum rubber and rubber cement shall be suitable

for making field connections in rubber water stops.

Tensile strength (min) 2.1 KN/cm2

Elongation at break (min) 500%

Hardness degree (shore) 60-65

Compression set by constant Deflection Method maximum

% of original deflection: 20%

Water absorption after 48 hours at 700C (% by 5%

weight)

Accelerated against test (48 hours at 700C and 21 Retention of initial tensile

kp/cm2 of oxygen) strength not less than 75%.

Retention of initial elongation at break < 75%

Rubber water stops and all necessary related intersection pieces and materials

shall conform to the relevant standards.

12.4 Water swelling rubber sealing materials

This water swelling rubber sealing strips shall be applicable to concrete, steel

and plastic surfaces to seal joints if water will come in contact with the material. The

sealing strips shall be built in accordance to plans and to the satisfaction of the

Employer. Placing shall be done according to manufacturer's instructions.

A manufacturer's written guarantee for water tightness and ageing-stability will

be needed for approval prior to placing.

The swelling rubber material shall have the physical properties mentioned as follows:

- Tensile strength (min) 2.0 kN/cm2

- Elongation at break (min): 500 %

- Volume coefficient of expansion (min): 2

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11.7

11.7.1

- Hardness degree (shore):

- Vulcanization:

Metal Seals

General

20-40

shall be possible

Details of type and placing of seals shall be as approved by Employer. The

seals shall be jointed carefully together by welding or brazing so as to form continuous

water-tight diaphragm in the joints. Adequate provisions shall be made to support and

protect the seals during progress of the work.

11.7.2 Materials

Materials for metal seals shall conform to the following specifications unless

otherwise approved in writing:

iii) Welding Rods – Welding rods shall be of a type and composition confirming to IS:

5898-1970 “Copper and Copper alloy welding rods and wires and magnesium

alloys welding Rods” IS 5856-1970 “Corrosion and heat resisting chromium-nickel

steel solid welding rods and bare electrodes”, for welding the copper or corrosion

resisting steel specified above.

12.5 P.V.C. Water Stops

12.5.1 General

PVC water stops of the types approved by the Employer shall be installed at

expansion, contraction & construction joints. PVC water stops are profiles, based on

specially formulated plasticized PVC compositions, available in different design such

as serrated (ribbed) as with central bulb.

12.5.2 Material

The PVC water stops shall be fabricated from virgin plastic compound the basic

resin of which shall be polyvinyl chloride manufactured by reputed concerns. The

compound shall contain any additional resin plasticizers, inhibitors, or other materials

such that, when the material is compounded it shall meet the performance

requirements given in these specifications. Reworked PVC of the same composition

generated from the manufacturer‟s water stops production may be used. Reclaimed

PVC shall not be used.

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All water stops shall be extruded type and manufactured in such a manner that

the finished product shall be dense, homogenous and free from porosity and other

imperfections that might affect durability or performance.

12.5.3 Definitions

a) Reworked P.V.C: It is the material obtained from a finished product in the

fabrication of which only virgin P.V.C. was used. The material is intended for use

by the same manufacturer in the refabrication by the same process, of a similar

product. Reworked P.V.C. can be blended with only virgin P.V.C. of the same

composition and quality as the original material, the source of supply being the

same for both.

b) Reclaimed P.V.C. : It is a reused material that fails to meet the requirements of

reworked PVC as defined above.

12.5.4 Properties

The material shall have the following physical characteristics as recommended

by Central Water Commission:

No. Characteristics Unit Values

1 Tensile strength Kg/Cm2 116 minimum

2 Ultimate Elongation % 300 minimum

3 Tear resistance Kg/Cm2 49 minimum

4 Stiffness in flexure Kg/cm2 24.6 minimum

5 Accelerated extraction Tensile Kg/cm2 105 minimum

strength % 250 minimum

Ultimate elongation

6 Effect of Alkali 7 days

Weight increase % 0.25 maximum

Weight decrease % 0.10 maximum

Hardness change Point 5.0

7 Effect of Alkali 28 days

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Weight increase % 0.4 maximum

Weight decrease % 0.3 maximum

Dimension change % 1.0 maximum

NOTE: - In respect of the tensile strength (under „1‟above) a higher value of about 140

Kg/cm2, with corresponding change in related values, shall be preferred.

12.5.7 Installation and jointing

a) Installation

The installation consists of embedding half the width of the water stop in

concrete, leaving the second half open. After concreting the first half, the second half

is also embedded leaving the central bulb free for expansion and contraction. It is

important that during placement of concrete, the water stop shall not be deformed due

to impact. The concrete shall be properly vibrated so that it develops intimate contact

with the water stop. Care shall be taken so as not to reduce effective cross section of

the water stop.

It is necessary that PVC water stops are placed near the centre of thin concrete

walls and about 150 mm away from the outside face of thick concrete walls.

Suitable precautions shall be taken to support and protect the water stops

during the progress of the work and any damaged water stops shall be repaired or

replaced. PVC water stop shall be protected from direct sunlight. The exposed parts of

these water stops which are partially protected in shall be protected by timber boxes

or other satisfactory means.

b) Jointing

During the installation, PVC water stops are often required to be jointed. There

are essentially two types of joints.

1) Straight joints

2) Mitred joints

Jointing shall be carried out as per instructions of the manufacturer. However,

the following method is suggested for general guidance.

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1) Straight joint

i) Water stops are cut at the point of jointing by means of a cutting device such as

handsaw or sharp knife. The cut shall be smooth so as to result in close mating

of the surface.

ii) A heating plate with a wooden handle is heated to about 2000o C by blow lamp

or any other means. The heating plate shall not be overheated as it results in

charring of the PVC material.

iii) Two ends of the PVC water stops to be joined are pressed uniformly against hot

heating plate till the PVC material is fused. The heating plate is pulled back and

both ends are pressed together uniformly until the joint cools down to ambient

temperature. It is essential that the entire cross section of the water stops is

uniformly fused on heating. During the process the alignment of the complete

cross section especially the centre bulb shall be maintained.

2) Mitred Joints

Cross, L-shaped or T-shaped mitred joints can also be formed by fusion

method, described above for straight joints. This involves some experience to obtain

perfect joints. In case there is difficulty in attaining perfect joining, factory made

intersection pieces may be obtained from the manufacturer and their jointing with the

straight pieces carried out as described for straight joints.

Inspection of joints is necessary to ensure that all joints are properly made and

are water tight, and, that the water stop is properly located in the form. Placing of

concrete shall not be allowed to start until the location and condition of water stops

has been inspected and approved.

12.5.8 Inspection and Tests

a) General

Before placing order, the manufacturer shall be required to furnish latest test

certificate of all tests carried out on test specimen prepared from the same batch of

PVC compound as used in the manufacture of the PVC water stops for properties

specified under Clause 7.6.4 from reputed test house such as National test House,

Alipore, Calcutta. In addition, before acceptance of the materials, PVC water stops

78

shall be subjected to Laboratory tests for characteristics given under Clause 7.6.4.

Material for tests shall be furnished by the manufacturer and all tests shall be carried

out at their own works or if such facilities are not available then at approved test house

in the presence of S.E./ Director, Inspection & Control or his authorized agent.

General sampling procedure shall be as laid down in 7.6.6(b).

b) Sampling for Tests

Sampling for laboratory tests to determine physical properties of the compound

shall be taken at random to obtain the following number of test units from each

separate purchase order.

Size of purchase order No. of test unit

150 metres or less 1

151 to 300 metres 2

301 to 1500 metres 4

1501 to 3000 metres 8

3001 metres and above 15

Laboratory tests to determine physical properties of the PVC water stops,

required under these specifications, shall be performed on test specimen taken from

the finished product.

c) Tests : The test and the test procedures for the various properties of the material

given in clause 7.6.4 are described in Annexure-A.

11.7.3 Procurement and storing

PVC water stops shall be procured in rolls to facilitate handling. The inside

diameter of rolls shall not be less than 300 mm. Any roll of water stops, which is not to

be installed in the structure within 6 months after receipt of the material, shall be

loosened. All water stops shall be stored in as cool a place as practicable preferably at

27o C or less. Water stops shall not be stored in the open or where it will be exposed

to the direct rays of the sun.

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11.7.4 P.V.C. Joint Strips

PVC joint strips, shall be used in the exterior face of the 25 mm expansion

joints as directed by the Employer.

For „Material & Fabrication and „Inspection & Tests‟ refer clause 7.6.2 and 7.6.6

respectively for PVC water stops.

11.8 Under drainage of Bye pass Channel and Special lining portion of hydel

Channel

Bye pass channel: Under drainage of bye pass channel shall be provided to

safe guard it against pressure exerted by sub soil water on it. The arrangement shall

consist of network of longitudinal drains and cross drains along with Pressure relieve

valves at suitable junction points of drains in the bypass channel in order to release

the uplift pressure on the bed of the various components of bye pass channel viz.

crest, glacis, cistern etc as per approved design. A minimum of 2 numbers of

longitudinal drains shall be provided along the length of bye pass channel and cross

drains should be provided at suitable intervals keeping in view of the presence of sub

soil water level however this distance shall not be more than 10 m in cistern portion of

the falls of bye pass channel or as approved by the Employer.

Special lining portion of hydel channel: A filter blanket shall be provided up to

depth of 3.7 to 4.3m below top of lining in this portion i.e. up to the minimum FSL in

channel. The filter blanket should be connected to longitudinal drains in the bed by

providing cross filter drains along the slope of the channel at 7.5m centre to centre.

Two longitudinal PVC/Asbestos Cement perforated pipe drains laid in trenches filled

with gravel and surrounded by graded filter layers along with cross drains at 45m

centre to centre shall be provided in special lining portion and that this network should

be in consonance and is connected to the hydel channel portion upstream or

downstream of special lining portion of hydel channel. Pressure relief valves should be

provided on longitudinal and cross drains in bed at 90 m centre to centre but should

staggered in adjacent rows.

The longitudinal and cross drains in bye pass and special lining portion of hydel

channel should be trapezoidal with bottom width as 500m and depth 525mm with side

as steep possible. The PVC/Asbestos Cement pipe should preferably of 150mm

80

diameter with 12mm diameter holes/perforation. On an average there should be a

minimum of 100 perforations/holes per meter length of pipe and these

perforation/holes shall be staggered in adjacent rows. The pipe should shrouded by

suitable filter. All pipes and fittings shall be maintained clean during the progress of

work and care should be taken that filter should not clog during construction. If any

pipe becomes either partially or wholly clogged, it shall be satisfactorily cleaned or

replaced. IS: 4558- 1995 shall be referred to for any other detail as required in field

during construction. The PVC pipes shall confirm to IS 4985-1988 and Asbestos

Cement pipe shall confirm to IS 9633-1980.

No work shall be covered over or surrounded by concrete until it has been

inspected and approved by the Employer. The entire work shall confirm to Punjab

PWD specifications or relevant IS coded or as directed by the Employer.

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ANNEXURE-A

TESTS AND TEST PROCEDURE FOR PVC WATER STOPS

1. Tensile properties

Each test specimen shall be tested for tensile strength, ultimate elongation and

arithmetic mean result shall be calculated for each property. The calculated

results shall satisfy the requirements given in clause 7.6.4.Method of test shall

be in accordance with ASTM D-638 or equivalent. Test specimens shall be type

IV.

2. Tear Resistance

Each test specimen shall be tested and arithmetic mean result shall be

calculated. The calculated result shall satisfy the requirement given in clause

7.6.4.The method of test shall be in accordance with ASTM D-624 or

equivalent. Test specimen shall be cut by Die „B‟ as per above ASTM.

3. Effect of Alkali

Test specimens shall be prepared as per type IV of ASTM D-638 or equivalent

and the specimens shall be weighed singly to the nearest milligram.

The Alkali treatment will be as follows:-

The specimens shall be individually totally immersed in a solution consisting of

5.0 gm chemically pure sodium hydroxide and 5.0 gm chemically pure potassium hydroxide dissolved in one liter of distilled water. The solution shall

be maintained at 95 20 o C.

Effect after 7 days

After seven days, the specimens shall be removed rinsed, surface dried and

prepared for reweighing according to ASTM D-471 or equivalent except that the

acetone dip shall not be used. The Alkali treated specimen shall be weighed

singly to the nearest milligram and the arithmetic mean change in mass shall be

calculated in percent. The calculated result shall satisfy the requirements given

in clause 7.6.4.

Each Alkali treated test specimen shall be tested for hardness in accordance

with ASTM D-676 or equivalent using the Shore Durometer and the arithmetic

mean result shall be calculated. The calculated result shall satisfy the

requirement given in clause 7.6.4

Effect after 28 days

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The dimension of the specimens shall be measured to the nearest 0.001 inch

and the specimens weighed to the nearest milligram and both observations

recorded.

The specimens shall then be subject to the effect of Alkali for 28 days, after

which they shall be removed, rinsed, surface dried and reweighed. The

arithmetic mean change in mass shall be calculated in percent. The calculated

result shall satisfy the requirement given in clause 7.6.4.

The Alkali treated test specimens shall also be measured to the nearest 0.001

inch and the arithmetic mean change in length shall be calculated in percent.

The calculated result shall satisfy the requirement given in clause 7.6.4.

4. Stiffness in flexure

A specimen 1” width and 2” in length shall be fixed in a vice, having jaws of the

smooth flat type, with one half of the length of the specimen free of jaws. The

vice shall be fixed to a suitable base and placed in universal testing machine.

The specimen shall be subjected to loading as a cantilever beam with the point

of loading at a position ¼” from the face of the vice jaws. A loading head of

greater width than the specimen and of suitable length shall be used to apply

the load. The loading head shall be of ½” material and shall be braced to

prevent any flexure under load. The loading face of the head shall be ground to

one side to form a knife edge and sufficiently founded to prevent gripping of the

specimen material by the head. The rate of loading shall be 0 2” per minute.

The stiffness in flexure shall be determined from the material load deflection

characteristics.

5. Accelerated extraction test

Each test specimen conforming to the shape and dimensions given in ASTM D- 412 or equivalent, using Die „C‟ as per ASTM shall be cut from the sample

submitted and weighed to the nearest milligrams. The specimens shall be

subjected to the same test as for „Effects of Alkali‟, continuously for not less

than 11 days after which, provided they have reached constant weight, they

shall be tested for tensile strength and ultimate elongation as per ASTM D-638

or equivalent. Under no circumstances, however, shall the specimen be tested

for tensile strength until they have reached constant weight. Constant weight is

assumed to have been obtained when the successive daily readings do not

differ from one another by more than 0.05% of the original weight.

Joints in the board shall be finished flush with fillers. Necessary cutouts for

electrical / AC fixtures shall be provided with a framing of wall channels.

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3. Earthwork Specifications Canal

1.0 SCOPE

These specifications shall govern the general requirements and methods for

earth work, covering excavation and construction of embankments of Ravi Canal

and do not include the excavation relating to bridges and other works.

The excavations as herein defined include the disposal and transportation of

the excavated material to the adjoining filling reaches or as spoils, if necessary.

2.0 PLANNING

2.1 Prior to the commencement of a work, all relevant data shall be collected and

drawings prepared showing the location of the excavation, and embankment

reaches separately. On these drawings, both the excavation and filling reaches

should be distinctively indicated separately and the quantity of material to be

excavated and placed in fill stated in these reaches. This information would be

useful to ensure economic hauls throughout the work. Where the material to be

excavated consists of different types and if the various types have to be used

separately in the fill or run to spoil tip, the quantities of each class of material in

each area should be shown on drawings.

From the nature of material to be excavated and method of its disposal, the type

of excavation, the length of haul and the amount of compaction necessary, it is

possible to select the most suitable 0type of plant for a particular job.

2.2 No earthwork on canals should be started unless proper acquisition and

demarcation of land has been finalized and permission of concerned

organization obtained. Such land shall be demarcated by fixing permanent

boundary stones at intervals of 0.2 Km. on both sides on straight reaches and at

points where there is change in direction or change in land width. Similar

precautions shall be taken for defining the borrow areas also. Such areas will be

temporarily acquired and suitably demarcated.

3.0 SETTING OUT

3.1 Prior to the commencement of work, the centre line of the proposed channel

shall be marked by stones or pegs, each at about 30 metres. Curves shall be

laid out; top and bottom edges of the excavation and toe of all embankments

suitably peg marked. Reference pegs should also be driven into ground at a

fixed distance outside peg markings. All levels shall be referred to an established

bench mark not subject to subsidence or interference.

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3.2 Profiles of designed canal section in fill and moderate cut reaches may be

marked at 25 m intervals in curves and 50 m in straight reaches.

4.0 CLEARING

4.1 The land over which embankments are to be formed and other excavation is to

be carried out, shall be cleared of all trees, stumps, roots, bushes, rubbish ant-

hills and other objectionable matter. The cleared material shall be suitably

disposed off.

4.2 All waste materials to be burned shall be piled neatly and when in suitable

condition shall be burned completely. Piling for burning shall be done in such a

manner and in such a location as to cause least fire risk. All burning shall be so

thorough that the materials are reduced to ashes. Necessary precautions shall

be taken to prevent fire from spreading to areas beyond the limits of cleared

areas. Suitable equipment shall be supplied for use in preventing and

suppressing fires and shall be kept available at all times.

4.3 In filling reaches, all holes and hollows whether originally existing or produced

by digging up stumps and roots, shall be filled with suitable earth, well rammed

and levelled off.

4.3.1 In filling reaches, the boulders in the top strata shall be removed and filled

with suitable material.

4.3.2 Boulders which may interfere in the work should be generally removed

after breaking them down, if necessary.

4.3.3 It is desirable to protect the trees outside the outer edge of the canal

embankments. However, the presence of trees in the vicinity of the canal can

accentuate variation of moisture content in the sub – stratum. In the case of

expensive spoils such excessive moisture variation can result in damage to the

lining. Such influence is believed to extend to distances equal to twice the height

of the tree.

5.0 STRIPPING LOOSE MATERIAL

5.1 Before excavation work is taken up, all loose material close to the area to be

excavated which is liable to fall or otherwise endanger the workmen or works

shall be stripped. The method used shall be such as not to shatter or render

unsuitable or unsafe any formation which is originally sound.

6.0 EXCAVATION

6.1 GENERAL

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6.1.1The excavation for the Link canal in cutting reaches shall be done according

to the drawings issued by the Hydel Designs Directorate, Chandigarh.

6.2 EXCAVATION – BASIC REQUIREMENTS

6.2.1 The excavation in the canal section, where lining is to be provided, shall not be

done to the final grade as shown in the drawings in the first instance. To begin

with adequate margin to be decided by the officer designated as a Inspector

shall be left to provide for settlement and ravelling travel and for sub surface

preparation for the lining, provided that a minimum of 150mm excavation to the

final designed grades on bed and sides is the left to be done immediately before

the lining is laid. The aforesaid 150mm of the material shall be excavated

carefully at the time of preparation of the sub grade for the laying of lining.

6.2.2 The excavation slopes as shown on the drawings must be adhered to.

6.2.3 Canal section shall be excavated as shown on the drawings or as directed by

the engineer- in- charge. Both edges of the bank, especially the inner one shall be

neatly aligned symmetrically to the centre line of the channel. They shall be

absolutely straight in straight reaches and smoothly curved on bends. All gangways,

roads and stoppings shall be such that they fall within the canal section so that final

dressing of slope will consist of digging only and no filling will be required.

6.2.4 Suitable arrangements for drainage shall be provided to take surface water

clear of the excavation during the progress of work. Sumps may be constructed

at suitable places and water collected may be pumped out. When cutting on

sloping ground, it is advisable to cut a catch water drain on the higher side to

prevent water from flowing down the cutting slope.

6.2.5 Whenever ground water is met during excavation adequate measures shall be

taken to dewater the cutting. The choice of method to be employed and type of

equipment to be used would depend on the nature of ground and the volume of

the water to be dealt with.

6.2.6 If there is a continuous flow of water a sub drain with sumps at the intervals

may be installed. Drainage will be helped by excavating from downstream side

to upstream side so that water tends to drain away from the working face.

Generally area is drained by providing pilot cut to natural valley so as to drain

the sub soil water.

6.2.7 In case of lined canals sub soil water shall not be allowed to accumulate in the

bottom of the canal and pumping arrangements shall be so organized as to deal

with any temporary flood water which may occur. As described above (6.2.4,

6.2.5 and 6.2.6) the subsoil water should be

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drained by providing drain or pumping the sub soil water so as to keep the area

dry as far as possible.

6.2.8 Excavation may be carried out by manual labour or by excavating machines.

The choice of type of excavating machine to be used will depend on the nature

and quantity of material to be excavated and also on the leads and lifts involved.

6.2.9 Exploratory holes and type of soil shall be determined before excavation. The

permeability characteristics of the soil encountered should be accessed by

making use of in place permeability tests as required. Canal sub grade soil on

the slopes and bottom with respect to probable future seepage and erosion

should be examined.

6.2.10 Above the lining, the rock may be allowed to stand at its steepest safe

angle and no finishing is required other then removal of rock masses which are

loose and are liable to fall.

6.2.11 Lined sections in the areas of high ground water shall be protected against

uplift by drainage system as per IS 4558- 1995- “Code of practice for under

drainage of lined canals” (Second revision). If fine grain soils (sand) are to be

placed as sub grade below concrete or membrane lining, this should be without

organic matter, gravel, pebbles etc. Natural sub grade should be inspected and

organic material, gravels, pebbles, protruding should be removed from sub grade.

Filter blankets should be provided beneath lining as per IS 4558-1995 to release

uplift pressure. All washable materials and any soil which generally becomes

unstable on saturation such as organic soil, loose , silts, expansive clays are

generally removed or properly treated for embankment and canal lining so as to

provide safe and stable sub grade under operating condition.

6.3 METHOD OF EXCAVATION

6.3.1 Excavation shall be done by standard excavation equipment such as rippers,

power shovels or bull-dozers and by such techniques as conform to the best

current practice for such works, as are required to reduce the over excavation, if

any, to the minimum.

6.4 ROCK EXCAVATION

6.4.1 Rock may be excavated by the following methods:-

a) Quarrying out by hand with suitable rock wedges and hammer steel bars, picks

etc. and breaking with rock hammers.

b) Loosening by use of pneumatic paving breakers.

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c) Drilling suitable holes by hand with hand jumpers or pneumatic drilling

machines and breaking up rock with plugs and features.

d) Drilling holes by hand jumpers or pneumatic drilling machines as above, but

breaking the rock with suitable commercial explosives or blasting devices.

e) Ripping with suitable heavy duty tractors where the rock formation falls within

the range of repability of commercially available units.

6.4.2 Excavation of rock is usually done by loosening and removing the rock by

forming a slightly sloping open face across the cut and working towards this

open face. The depth and width of this face will vary according to the nature of

rock and method adopted. Several faces may be worked simultaneously, one

behind the other, with benches between each face; the space between the faces

and length of each method adopted for removing the rock. Provided that proper

equipment and technique are adopted, drilling and blasting is the most speedy

and economical method for excavating hard rock. For soft rocks ripping may

loosen the rock at greater speed and at much less cost.

6.4.3 Blasting shall be restored to only when absolutely necessary and shall be kept

to the minimum. Blasting where permitted by the officer designated as Inspector,

shall be carefully controlled to minimize the over breaks and preserve the

formation in the soundest possible condition beyond the minimum lines of

excavation wherever it becomes apparent that further blasting may loosen or

otherwise damage the slopes, the use of explosives shall be discontinued and

excavation completed by methods other than blasting.

6.4.4 Final cutting for 45 – 60 cm in hard rock shall be carried out by controlled

blasting or trimming or with the help of pneumatic paving breakers.

6.5 DISPOSAL OF EXCAVATED MATERIAL

Excavated material suitable for use in the filling reaches of the hydel channel shall be

used directly in the appropriate reaches to avoid rehandling. Material which are

not considered suitable for fill by the officer designated as Inspector shall be

systematically placed on the spoil banks in a manner indicated on the respective

drawings or as directed at site by the officer designated as Inspector.

6.6 PREPARATION OF SUB GRADE:

6.6.1 The excavation and Preparation of sub grade shall be done in accordance with

IS: 3873 – 1993 “ Code of Practice for lining in - in situ cement concrete lining on

canals. Where the original ground surface is below the grade of the canal the

bottom of the canal shall be filled to the grade in a manner prescribed for the

construction of canal embankments. In so far as

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practicable the finishing operation required on canal sections shall be performed

simultaneously with canal excavation.

6.6.2 The sub grade and embankment for a canal may comprise of rock or soil.

Canal sections excavated in rock should be inspected to examine whether joints

or fissures exists which will cause excessive seepage or piping. In case this is

so, rock will require grouting of the section before lining. Rock surfaces on which

compacted earth is to be placed should be moistened before placing the first

layer of earth but standing water should not be allowed. The minimum soil cover

over rock should be 225 mm.

7.0 FILLING REACHES

7.1 DEFINITION OF CANAL SECTION

For the purpose of these specifications, the term canal section shall be defined

as all zones, special fill and parts thereof, above the foundation surface and

within lines and grades as shown on the drawings or as otherwise directed by

the officer designated as Inspector as the limits of the canal section.

7.2 DEFINITION OF MATERIALS

7.2.1 The section for filling reaches of link canal will be shown on approved

drawings. The sections may be classified as under:-

I) Normal filling reaches

II) Special reaches

I) Normal Filling Reaches

The filling part of these reaches will be divided into following fill zones:-

Impervious Fill zone No.1

Suitable earth material as per limiting grading curves shown in plate-4, spread in

150 mm layers compacted to 98% of the maximum dry bulk density or higher at

moisture content varying from optimum moisture content (O.M.C.) to 2% drier of

O.M.C.

Filter Fill zone No. 2

Selected free draining clean sand and gravels as per grading curves. The filter

material shall be placed in position in wet condition and compacted in 250 mm

layers. The minimum relative density of the compacted material shall not be less

than 70 percent.

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Zone No. 3 Toe Drain – Gravel and cobbles as per limiting grading curves.

Pervious fill zone No. 4

The rest of the compacted zone shall consist of pervious fill material consisting

maximum size not more than 150 mm and not containing more than 5% fines

passing No. 200 sieve generally. It should be spread in 250 mm layers and

compacted to achieve minimum 70 percent relative density.

II) Special Reaches

These reaches shall cover portions adjoining to drainage works and other parts of

the canal where normal methods of placement and compaction are difficult to

work. Special specifications shall be issued on receipt of specific references of

such problematic reaches from the field.

7.3 GRADATION REQUIREMENTS

Limiting grading curves of material for different zones of the canal embankment are

shown in plate – 4.

7.4 SOURCES OF FILL MATERIALS

Zone No. 1 - Material for this zone shall be obtained from borrow areas approved by

the Board of Consultants (BOC) for the Shahpurkandi Dam Project and

conforming to the specified grading limits.

Zone No. 2 - Material for this zone shall be obtained from suitable borrow areas viz.

bed of khads; screening or processing if necessary shall be done to obtain

suitable material conforming to the specified grading limits.

Zone No. 3 - Material for this zone shall also be obtained from bed of khads;

suitable borrow areas or suitable rejects from a screening plant.

Pervious fill zone No. 4

Economics permitting, the material for this zone shall be obtained from the

cutting reaches of the Hydel Channel and any deficiency thereof shall be

supplemented from borrow areas duly approved by the officer designated as

Inspector. It shall conform to the specified grading limits in plate-4.

7.5 PRODUCTION OF FILL MATERIAL

7.5.1 Investigations:- Materials from the cutting reaches and borrow areas (where

necessary) shall be completely investigated and the engineering and index

properties of the material to be used in the canal filling sections shall be

established well in advance of construction. Distribution charts shall be

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prepared indicating the reaches from where the material will be available and the

reaches where the material shall be utilized.

7.5.2 CLEARING AND STRIPPING

All borrow areas and the area of cutting reaches shall be stripped of top soil, sod,

loam, vegetation and other material which is unsuitable for filling, and the same

shall be disposed off separately at the places to be designated by the officer

designated as Inspector.

In case the excavation from cutting reaches are stockpiled for subsequent use, the

top surfaces of these stockpiles shall be maintained free of vegetation.

7.5.3 EXCAVATION OF MATERIAL

The material from cutting reaches and other approved borrow areas shall be

excavated by a power shovel or a scraper or any other suitable means as

directed. The material shall be excavated in a way that it forms a homogeneous

mixture for the particular zone.

7.6 FILL PLACEMENT

7.6.1 SCOPE

This section shall cover all work of placing material necessary for the construction of

canal sections to the lines and grades shown on the drawings. All operations of

construction viz. spreading, moisture conditions, compaction etc. of materials

shall be carried out in accordance with the requirement of this section or those

specified from time to time.

7.6.2 GENERAL

Before commencing the work, the toe of the slope on each side of the banks

shall be lock – spitted (Dag – Belled) and marked by pegs, firmly driven into the ground

at intervals of about 20 m. Profiles made by bamboos, earth or other convenient

materials and strings shall be set up for the guidance of the workmen at about 50 m

apart over straight reaches and about 25 m apart at curves. In setting up the profile for

an embankment a suitable allowance shall be made for settlement.

Masonry blocks shall be constructed at each profile to indicate the centre line

as also the bed level of the canal before starting the entire earthwork.

Embankments shall be built to the height and slope as shown on the drawings.

All the edges of the embankment shall be neatly aligned symmetrical to the centre line

of the channel. They shall be absolutely straight in reaches and smoothly curved at

bends.

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The top of each embankment shall be levelled and finished so as to be

suitable for roadway and given a cross outward slope to drain away rain waters. The

bank carrying inspection road shall be given a suitable cross slope.

For embankment in which controlled compaction has not to be carried out,

suitable allowance be made for settlement.

An allowance of about 10% for settlement is recommended for embankments

in which controlled compaction has not been carried out.

The canal section shall not be constructed to the lines and grades shown on

the drawing in the first instance. A plus margin of 450 mm minimum will be given on the

inner face of the embankment slope to be lined in case of filling. This additional

compacted soil will be removed (Lip-cutting) from the inner slope of the embankment

subsequently just prior to placing the lining and the filter behind the same.

Placement of the fill within the zone shall be controlled by the embankment

inspector in an orderly sequence and in an efficient and workmanlike manner so as to

produce fills having specified qualities of density, strength and permeability as well

ensure the highest practicable degree of stability and permanence of the whole

embankment.

7.6.3 PREPARATION OF FOUNDATION SURFACE

Before the earthwork in each reach is started, the area within the specified

limit of the drawing shall be cleared of all trees, roots, rubbish and other objectionable

material. The material so removed shall be burnt or otherwise disposed off or removed

to a safe distance in a way that it does not interfere or mix with the earth work to be

carried out. No fill shall be placed on any part of the foundation surface unless that part

has been inspected, surveyed and approved in writing by the officer designated as

Inspector as ready for fill placement. No slopes against which the fill is placed shall be

steeper than 1:1 In case steeper slopes are encountered they should be flattened by

suitable excavation.

The surface of each portion of the foundation immediately prior to receiving

material for the earth fill shall be moistened and compacted by a few passes of roller.

When in the opinion of the Inspector such prepared surfaces are too dry or

smooth to bond properly with the first layer of the fill material to be placed thereon,

they shall be sprinkled with water and worked with harrow, scarifier or other suitable

equipment in an approved manner and to an extent and depth sufficient to provide a

satisfactory bonding surface before the first layer of fill material is placed. Similarly

where the foundations surface is considered to be too wet, adequate arrangements for

its drainage shall be made.

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7.6.4 PLACEMENT: The distribution and the grading of the material throughout the canal section shall be approved by the inspecting authority, the coarser material being preferably placed on the outer side of each zone .The fill shall be free from lenses, pockets or layer of material differing substantially in texture or gradation from surrounding material. The combined dumping, spreading and compacting Operation shall be such that the material will be blended sufficiently to secure the best practical degree of compaction and stability.

Successive loads of material shall be deposited parallel to the canal alignment

and at proper spacing in order to obtain a uniform spread thickness with a minimum

amount of dozing.

The material in the canal section shall be placed only when the weather

conditions are satisfactory to permit accurate control of moisture content during that

period of construction when placement is suspended and embankment may be subject

to rainfall , the section shall be graded and rolled with a smooth wheeled roller to

facilitate run off. The top surface shall be given a 2% slope to prevent accumulation of

water on the embankment.

Prior to resuming the work after shut down the top surface shall be slightly

scarified and moisture adjusted, if necessary.

The incomplete ends of the canal embankment shall be placed at the slope not

steeper than 1 in 3 to permit satisfactory bonding with the portion of the embankment

which is constructed later.

Zone 1:- The material for the zone shall be spread in continuous approximately

horizontal layers of such loose thickness so that the compacted layer thickness does

not exceed more than 150mm.Rock fragments or cobbles having maximum

dimensions of more than 10 mm shall not be placed in this zone. Large size fragments

of material which is not likely to be crushed under the feet of sheep foot roller shall be

removed during the spreading operation. The embankment inspector shall direct the

placing in such manner that more clayey material is located towards the inner edge of

the embankment.

After the layer has been properly placed, the embankment inspector shall

determine the moisture content of the material. When the surface of any layer of earth

fill is too dry to bond properly with the layer of the material to be placed thereon , it

shall be moistened in an approved manner , when the surface of any layer of earth fill

placed is too wet for the proper compaction of layer of earth fill to be placed thereon , it

shall be removed , allowed to dry or worked with harrow, scarifier or other suitable

equipment to reduce moisture content to the required amount and then it shall be re-

compacted before the succeeding layer of earth fill material is placed.

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Prior to or during compaction operation, the fill material shall be conditioned so

that the optimum practicable moisture content required for compaction purpose is

uniformly distributed throughout the layer. The moisture content shall be kept within the

limit specified for zone 1 under paragraph 7.2.1 ( I ). If the addition of water to the fill

material is necessary, for such moisture conditioning water shall be added before

rolling of the layer. The addition of water shall be done by controlled sprinkling followed

by such mixing as is necessary to obtain uniform moisture content increase throughout

the material. Care shall be taken not to place too drier or too wetter material than that

specified.

Zone 2:- The material for this zone shall be spread in 250mm thick loose layers and

thoroughly wetted before rolling. Rock fragments or cobbles having maximum

dimensions more than 20 mm shall not be placed in this zone. This zone should not

contain more than 5 percent fines passing No. 200 sieve generally.

Zone 3:- The material for this zone shall be dumped and dozed into place. Rock

fragments or cobbles having maximum dimensions more than 225 mm shall not be

placed in this zone.

Pervious fill zone No. 4 :- The material for this zone shall be spread so that the loose

layer thickness does not exceed 250mm.The material having maximum dimensions of

more than 150mm shall not be placed in this zone. This zone should not contain more

than 5 percent fines passing No. 200 sieve generally.

7.6.5. ROLLING

Zone 1:- After placement of the fill material as described under Para 7.6.4 above, it

shall be rolled as specified herein, such that the thickness of the layer after compaction

is not more than 150 mm.

The number of coverage of the compaction equipment shall be determined in

the field so as to give the specified compacted density.

Additional width of minimum 450 mm is to be compacted to leave a margin for

probable improper compaction on the inner edge of the embankment.

One coverage of the compaction equipment is defined as the action achieved

when the entire surface of a layer has been traversed at least once by the compacting

surface of the compactor, one pass is defined as the continuous motion the compactor

in one direction only. In case of sheep-foot roller, if one double drum roller is used its

one pass shall make one coverage of the area traversed. However if two rollers are

coupled one behind the other, their one pass constitute two coverages.

Compaction of each layer of fill shall proceed in a systematic, orderly and

continuous manner so as to ensure the specified coverage by the compactors. Rolling

shall be performed parallel to centre line of the channel.

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Zone 2 and Zone 4: - The material for these zones shall be compacted with vibrating

roller. The minimum relative density of the compacted material shall not be less than

70 percent.

Zone 3: - The material for this zone shall not be compacted but shall simply be

dumped and dozed into place, in reasonably level layers of thickness, as specified.

7.6.6 STAMPINGS

Special pneumatic or other tampers shall be employed for compacting fill

material to specified densities at location (such as reaches clause (ii) in para 7.2.1

where it is impracticable to use the equipment and procedure specified for placement

of the bulk of the fill.)

All material to be tamped shall be spread in layers not over 100mm thick

when loose, special care shall be exercised to obtain a good contact and bond with

surface of concrete / masonry structures.

8. QUALITY CONTROL

8.1 General

Shahpurkandi Hydel Channel is a power channel and, unlike irrigation canals, may

have to be run, without any seasonal or even annual closure for long periods. The

success of canal embankment depends on the control of the construction and

rigidness of inspection. Regular field tests shall be conducted and checks made in the

field laboratory by the inspection authorities to determine whether the desired results

have been obtained. Densities and moisture control for zones have been specified

under para 7.2.1 (I).

The following control tests shall be performed on the canal embankment:-

8.2 FIELD TESTS

8.2.1 DENSITY TESTS

The purpose of this test is to make a comparison of the condition of the

rolled materials to the desired standard of compaction in the laboratory.

Any of the following two methods may be used for density determination of zone 1:-

a) Sand replacement method in accordance with IS: 2720 (Part 28) – 1974.

(First Revision).

b) Core Cutter method in accordance with IS:2720 (Part 29) – 1975. (First

Revision).

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The quicker and more accurate method out of these should be selected on

the basis of experience. The size of the density hole shall be 200 mm diameter and of

350 mm depth. The dry bulk density of the compacted material shall be within the

limits prescribed in para 7.2.1.

For pervious material, the density may be determined by the water

replacement method in accordance with IS: 2720 (Part-33)-1971.

8.2.2. MOISTURE DETERMINATION TESTS

The water content of the samples taken during the field density test should

be lower than the water content of the material before rolling because of the time lag

for compacting and testing the material and due to the time required to dig the density

test holes, during which adequate protection against moisture loss is impossible. The

moisture content of the material before compaction should be determined by one of

the procedure suggested in IS: 2720 (Part II) – 1973 second Revision, Amendment-I.

8.3 LABORATORY TESTS

8.3.1 RAPID COMPACTION CONTROL METHOD (LABORATORY

COMPACTION OF FIELD DENSITY TESTS)

Upon receipt of soil samples from the field, laboratory shall process the

samples and result of field density tests shall be compared with laboratory maximum

dry density and the optimum water content for effective control over the construction

operation by the method given in IS:2720 (Part 38) – 1976, “Method of test for soils –

compaction control Test (Hilf method)”. The rapid control procedure provides the exact

percentage of laboratory maximum dry density and a very close approximation of the

difference between optimum moisture content and fill water content of the field density

sample, without determining water contents. Fill water content of the sample being

known, the values of field dry density, cylinder dry density at fill water content,

laboratory dry density and optimum water content shall be calculated and the results

shall be reported on Form (Appendix-I).

8.3.2 PERMEABILITY TESTS

These tests shall be performed on a few selected record samples in

accordance with IS: 2720 – Part 17) 1986 “Methods of test for soils – laboratory

determination of permeability (First revision)”. The coefficient of permeability of

impervious material should not be greater than 30 cm per year.

8.3.3 GRADATION ANALYSIS OF SAMPLES

Gradation analysis tests should be conducted on some of the samples

received from the field in accordance with IS: 2720 (Part 4) – 1985 “Methods of test for

Soils grain size analysis (Second revision)”.

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8.3.4. TRIAXIAL SHEAR TESTS

Undisturbed samples of approximate 200mm dia shall be taken from

representative locations for triaxial shear tests on 100mm specimens and results

reported. These tests should be conducted on materials in accordance with IS: 2720

(Part 12) -1981 “Method of test for soils-determination of shear strength parameters of

soil from consolidated undrained triaxial compression test with measurement of pore

water pressure (First Revision)”

8.4 THE DATA OF VARIOUS TESTS

The data of various tests shall be recorded in the relevant Performa given in

the relevant Indian standards referred to above. Consolidated statement of all the test

results for impervious and pervious fills shall be reported in Appendix I,II.

8.5 LOCATION AND PERIODICITY OF FIELD TESTS

The density and moisture field test shall be made to the following extent:-

a) In areas where degree of compaction is doubtful.

The area of doubtful density, where tests are to be made shall be detected

by observation by the embankment compaction inspector.

Possible locations of insufficient compaction include:-

i) Junction between areas of mechanical tamping and rolled

embankments.

ii) Areas where rollers turn during rolling operations.

iii) Areas where too thick layer is being compacted.

iv) Areas where improper water content exists in a material.

v) Areas where less than specified number of roller coverages were

made.

vi) Areas where dirt logged rollers are being used to compact the

materials.

vii) Areas where oversize rock which has been over looked is contained in

the fill.

viii) Areas containing material differing substantially from the average.

ix) Areas that were compacted by rollers which had lost possible part

of their ballast.

b) In areas where embankment operations are concentrated.

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c) For every 1530 Cum of embankment when no doubtful or concentrated

areas occur to check for density and moisture content.

d) In addition, one undisturbed sample for every 11500 Cum of materials

placed or at least one sample per week when fill is placed, shall be tested

for, in the laboratory for density, mechanical analysis and shear strength.

9.0 COMPACTION EQUIPMENT

9.1 All compaction equipment, together with their associated equipment, shall be

maintained in first class operating condition during all period in which they are required

for work on the embankment when compacting. Rollers are operated in sets or

random or sets of rollers operated one behind the other in the same track. All rollers

operated in this manner shall be of the same general dimensions, same width,

essentially the same weights and having the same operating characteristics. Tractors

used to pull roller shall be of types and of sufficient power to operate those units at full

capacity and maximum efficiency under the most adverse conditions to be

encountered.

Vibrating roller shall be used for compaction of the Filter Zone-2 and

Pervious Fill Zone-4 of the canal embankments.

9.2 Sheep foot roller shall be used for compaction of the impervious compacted fill or

zone 1, as the case may be. The number of coverages of the compaction equipment

shall be such as to achieve 150 mm thickness after compaction of spread layer and

the value of density equal to the specified percentage of the maximum laboratory

density attained in 1415 Ccm (1/2 cft.) mould with standard proctor effort. One

coverage of the sheep-foot roller shall consist one pass of each roller i.e. one pass of

two rollers coupled one directly behind the other shall constitute two coverages.

9.3.1 ROLLER DRUMS

Each drum of a roller shall have an outside diameter of not less than 1500

mm and shall not be less than 1800 mm in length. The space between two adjacent

drums when on a level surface shall not be less than 300mm nor more than 375mm.

Each drum shall be free to pivot about an axis parallel to the direction of travel. Each

drum shall be equipped with a suitable pressure relief valve.

9.3.2 TAMPING FEET

The tamping feet shall be of 200mm length welded to each drum in 20 rows,

6 to a row so that each drum shall have 120 teeth equally spaced. The space

measured on the surface of the drum between the centres of any two adjacent

tamping feet shall not be less than 225mm. The cross sectional area of each tamping

foot shall not be more than 65 Sq. cm. at a plane normal to the axis of the shank 150

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mm from the drum surface and shall be maintained at 45.00 sq. centimetre at a plane

normal to the axis of the shank 200 mm from the drum surface.

9.3.3 ROLLER WEIGHT

The loading used in the roller drums and operation of the rollers shall be as

required to obtain the desired break down and compaction of materials. The weight of

the Roller as used shall exert a unit pressure not less than 30 kgs per sq.cm. Tractors

used for pulling rollers shall have sufficient power to pull the rollers satisfactorily when

the drums are fully loaded with sand and ballast. The unit pressures exerted by the

roller drums shall be variable from about 15 kg/Sq. cm. to 52 kg/Sq. cm. with the

change in the load used in the drums. During the operation of rolling, the space

between the tamping feet shall be kept clear of materials which would impair the

effectiveness of tamping rollers.

10.0 MISCELLANEOUS

10.1 Height Differential: During the placement of fill in the canal section, every effort

should be made to have practically no differential elevation at the contacts between

Zone-2 and random fill or zones 1 and 2 as the case may be. However in no case a

differential of greater than 450 mm will be allowed.

10.2 Overlap: Whereas there would be no objection to compaction zone extending

into other zones, the overlapping fill material extending into other zones, the

overlapping fill material in compaction zone by other zones shall not be permitted.

10.3 FILTER THICKNESS

The thickness of filter zone as shown on the drawings, shall be taken as the minimum.

10.4 GRADATION

The gradation curve for any one sample from borrow areas must be within

the limiting grading curves at plate No. 4. Not more than 10% of the tests from the fill

should be outside the specified gradation limits at any point.

10.5 RELATIVE DENSITY

It is expressed in terms of void ratio by the following formula:-

DD

=

(emax – e) ÷ (emax – emin)

where,

DD

= Relative density, usually expressed as a percentage from 0 to 100.

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emax

e

emin

= Void ratio of the soil in its loosest state.

= Void ratio of the soil in the state of the test.

= Void ratio of the soil in its densest state.

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APPENDIX - I

SUMMARY OF FIELD AND LABORATORY TESTS OF COMPACTED FILL

Feature ___________________ Project _________________ Date of Report ____________ Period of Report

______________ Zone ____________

Remarks_________________________________________________ Equipment ___________________________

Use Separate sheet for reporting____________________________ Tests made in different zone.

Location of

Test

No.

test on embankment

Lift

thic

kn

ess

off

set

Sta

tion

and

Ele

vatio

n

1. 2. 3. 4.

S o u r c e o f m a t e r i a l B o r r o w a r e a r e q u i r e d , e x c a v a t i o n e t c . Methodofcompaction(numberof

tamperpassesorifpowertampered(PT

)

W e t d e n s i t y o f e a r t h a n d r o c k K g / m

% + 4 . 7 5 m m b y d r y w e i g h t Watercontentof

earthandrock(%of

dry

w e i g h t )

D r y d e n s i t y K g / m M a x . d r y d e n s i t y K g / m O p t . W a t e r C o n t e n t ( % o f d r y w e i g h t )

O p t . W a t e r C o n t e n t m i n u s F i l l W a t e r C o n t e n t ( W - W ) % o f

R a t i o o f f i l l d r y d e n s i t y o f c y l . Y c o n t e n t ( C i n % )

R a t i o o f f i l l d r y d e n s i t y t o L a b . M a x . Y % )

+ 4 . m m F r a c t i o n 7 5 - 4 . 7 5 m m F r a c t i o n

Characteristic

Field density test s of

Rapid Control Values Specific

Laboratory gravity

tests 3

3

wa

ter (D

in

3

d

at fill

d

5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17.

rate

cm

/ye

ar

Pe

rme

ab

ility

Test

Pe

rco

lation

18.

Triaxial shear test

C Ø

Mis

c. D

ata

19 20 21.

101

APPENDIX - II

___________________Project ______________________________Feature___________________________-

SUMMARY OF COMPACTED FILL AND LABORATORY DENSITIES

Test Dry Density Moisture Fill Roller Lab blows Location of Borrow pit Rolled ( R ) Remarks No.

% coverages / layers test location Power Tamp.

(P.T.)

Fill Laboratory

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

102

5. Specifications for Cement Concrete Lining

1.0 SCOPE

These specifications shall govern the general requirements and

methods for the lining of Canal, using in –situ cement concrete, plain or reinforced

as per relevant drawings.

2.0 TERMINOLOGY

For the purpose of these specifications, the following definitions shall

apply: -

2.1 COMPACTION

The densification of the soil by means of mechanical manipulation.

2.2 CONSOLIDATION

The gradual reduction in volume of a soil resulting from an increase in

compressive stresses.

2.3 CONSTRUCTION JOINT

A joint occurring in a structure composed of homogenous material,

such as earth or concrete, along a plane or surface formed by cessation of placing of

material for a time. Such a joint may be classified into a horizontal joint, a transverse

joint and a longitudinal joint.

2.4 EXPANSION JOINT.

A joint provided in exposed members between fix points to permit

longitudinal expansion and contraction when changes in temperature occur, and to

permit vertical movement where differential settlement is anticipated.

2.5 LIP CUTTING

Cutting of the extra width provided at the inner face of the bank under

compaction to allow for any lapses in compaction due to the inability of sheep-foot

rollers to cover the edge of the bank resulting from the safe limits set by different

operators of compaction machinery.

103

2.6 SLIP FORM

A steel plate provided at the leading edge of the slip form machine,

extending across the bottom and up the slopes of the canals to form the finished

surface of the lining.

2.7 SUB GRADE

The ground surface specially prepared against which lining shall be

placed.

3.0 MATERIALS

Materials to be used in the manufacture of cement concrete shall be as

prescribed here under:-

3.1 CEMENT

It shall be ordinary Portland cement conforming to IS-8112-(1989) or

Portland Slag Cement conforming to IS-455-(1989) or Portland Pozzolana Cement

conforming to IS-1489-(1991).

3.2 AGGREGATES:

Coarse and fine aggregates used, shall comply with the requirements

as numerated in IS:383-1970 ( 2nd

revision ) “Specifications for coarse and fine

aggregates from natural resources for concrete “.

3.3 WATER

Water used for concreting shall comply with the requirements of clause

5.4 of IS: 456-2000 (Amendments 3) “Code of practice for plain and reinforced

concrete”.

4.0 PREPARATION OF SUBGRADE

4.1 GENERAL

In preparation of subgrade for lining a margin of 150mm left in the bed

and 300 mm on sides in case of excavation and 450mm on sides in case of fill

placements, has to be removed immediately before taking up the operation of lining

104

(refer para 6.2.1 and 7.6.2 of specifications No. 25-SPK “Earthwork specifications for

Shahpurkandi Hydel Channel” ) This operation has to be done very carefully as

under:-

The subgrade shall be prepared perfectly and true to profile as shown

in the relevant typical cross-sections of the canal and according to correct levels

specified in the L-Section so as to provide a firm compacted bed for the lining. To

ensure correct formation of the subgrade, 300mm wide profiles shall be dug true to

the bed levels @ 7.5 metres interval and on the side slopes, @ 3.75 meters intervals

longitudinally, immediately before a reach is taken up for lining. Tiles or bricks shall

be fixed in this profile @ 3 to 4.5 meters apart (but away from sleeper locations) so

that the top surface of the tile or bricks is flush with the designed formation level of

the subgrade. These tile or brick-nishans shall be used for checking of final finish of

the subgrade and placement of lining. To ensure uniformity of side slopes, a chord

shall be stretched across two profiles, over a spacer of uniform thickness of 12mm. A

third spacer shall be run under the chord to check the evenness of the surface. This

process shall be repeated at short intervals along the slopes till the surface between

two profiles is properly levelled and dressed from top to bottom. Suitable wooden

templates may be used to layout and check the profile. Over cuttings of the subgrade

shall not be permitted. In case, any over cutting is done through the labour fault &

gharas are formed due to rain-fall etc. It shall not be allowed to be filled with the

earth but shall be filled with lean concrete in the manner described below:-

If the depression is 50mm or less, it shall be filled with stabilized mud

plaster with 5% admixture of cement. If the cutting is more than 50mm, it shall be

filled with mud concrete and shall be properly tamped to give uniform compact base.

The earth work reclaimed as a result of lip cutting of the sides and

levelling up of the bed, shall be used for the construction of dowel, completion of the

unfinished banks. In cutting reaches, the earth so reclaimed shall be used either for

widening or raising the spoils, as may be directed by the officer designated as

Inspector.

105

4.2 PREPARATION OF SUBGRADE IN EXPANSIVE SOILS

Lining should be avoided as far as practicable on expansive clays. But

if the canal has to traverse a reach of expansive clay and no alternative route or

construction type is economically feasible, any one of the practice detailed in paras

4.2.1 and 4.2.2 shall be adopted to reduce the damage to the lining depending upon

the swelling properties of the soil encountered.

Note: - clays vary so much in characteristics that the pressure required to prevent

expansion may be less than 0.07 kg/sq. cm. in some types and as much as 10.5

Kg/sq.cm. or higher in others. In many cases the practices recommended in paras

4.2.1. and 4.2.2 may not be adequate needing detailed investigation to find out a

practical solution. In such cases the method proposed to be adopted may followed

with the concurrence of the Hydel Designs Organisation.

4.2.1 If the expansive clay is in thin layer or in small pockets in an otherwise suitable

subgrade, it shall be over excavated and replaced with a suitable non-expansive soil

and compacted suitably.

4.2.2 If the swelling of the clay encountered, can be controlled by loading the surface

with a non-expansive compacted soil or gravel, the expansive clay bed shall be over

excavated to certain depth and filled to the grade of the underside of lining with

cohesive non –swelling material as prescribed in IS: 9451- 1994 (Amendments 2)

“Guidelines for lining of canals in expansive soils”. However, the excavated surface

of expansive clay shall be given a coat of asphalt before loading it to prevent the

entry of water into the clay.

4.3 PREPARATION OF SUBGRADE CONSISTING OF ROCK

The subgrade shall be prepared and dressed true to level and as per

required cross- sections of the canal.

All excavation including over breakage below lines of under-side of

lining shall be filled completely upto the lines of the under-side of lining with suitable

refill material such as lean concrete. Care shall be exercised in selecting the refill

material for use over fractured rock or cobbles because of the danger of washing

fines into the subgrade voids and thus loosing support. The selected material shall

106

be such as to resist such piping and, otherwise, should be selected for

impermeability and ease of placement.

4.4 PREPARATION OF SUBGRADE CONSISTING OF EARTH.

The subgrade shall be prepared, dressed and rolled true to level as per

the required cross-sections of the canal to form a firm compacted bed for the lining in

the manner prescribed in Para 4.1 above.

4.4.1 COMPACTION OF SUBGRADE IN PREDOMINANTLY SANDY REACHES

BED: The consolidation of the bed shall be done by over saturating the bed by

flooding it with water before lining is laid.

SIDES: The compaction of sides shall be done by over cutting the subgrade by

150mm and refilling it with lean mortar with adequate quantities of lime or 5%

cement admixture or by vibro compactors.

4.4.2 COMPACTION OF SUBGRADE IN OTHER THAN PREDOMINANTLY

SANDY REACHES.

All compaction shall be done at optimum moisture contents in layers

not more than 150mm thick to obtain a dry bulk density of not less than 98% of the

density at optimum moisture content obtained in accordance with IS:2720-1980 (

part-VII) ( 2nd

revision, amendments 2) “ Methods of tests for soils, determining of

water content –dry density relationship using light compaction “.

4.4.2.1 TREATMENT FOR NATURAL SOIL HAVING D.B.D. EQUAL TO

OR MORE THAN 1.8G/CU. CM .

Where the dry bulk density of the natural soil is equal to or more than

1.8g/cu-cm. initial excavation shall be done upto 150mm in the bed and 300mm on

sides above the final section as prescribed in para 6.2.1 of specifications No.25-SPK

“earth work specifications for Shahpurkandi Hydel Channel” and the cutting to final

shape shall be made immediately before lining.

4.4.2.2 TREATMENT FOR NATURAL SOIL HAVING D.B.D LESS THAN 1.8G/CU.CM

BED: - Where the dry bulk density of the natural soil is less than 1.8g/cu-cm and the

sub-soil water is near the subgrade, the consolidation shall be

107

done by undercutting the bed by 75mm and then ploughing upto 150mm below the

subgrade level. The loosened soil shall then be re-compacted with sheep foot rollers

or other suitable compaction devices.

Where the sub soil water is low requiring no dewatering and the dry

bulk density of the natural soil is less than 1,8g/cu-cm, the consolidation shall be

done by digging the canal up to subgrade level and after that loosening the earth

below subgrade upto 150mm by disc harrows or ploughing and compacting of the

same to a depth of 110 mm. After that the second layer of 150mm of earth shall be

laid over compacted layer by taking earth from lip cutting and compacting this to a

depth of 110mm. The compacted layer of 70mm above the subgrade level shall be

removed and the subgrade brought to design profile before laying the lining.

SIDES: Compaction on sides shall be done by manual labour or suitable compactors

to a depth of 300mm to obtain a minimum dry bulk density of not less than 90% of

the density at optimum moisture content.

4.5 ANTI-SALT TREATMENT

The soil in all reaches shall be tested for salt contents before the lining

is started. Where the salt content is over 1.00 percent or sodium sulphate is over

0.36 percent, the subgrade shall be first covered with about 2mm thick layer of

bitumen obtained by evenly spraying bitumen at a rate of about 2.35 kg/sq.m. to get

a good bond between bitumen and soil, crude oil at a rate of 60.5 kg/sq.m. should be

sprayed over it in advance of spraying bitumen. In case such a situation is

encountered only in small pockets, the replacement of subgrade upto a suitable

depth by suitable earth from adjoining reaches mixed with 5% cement and duly

stabilized should be considered, if economical.

Before spraying crude oil, subgrade shall be perfectly dry, clean and

free from dirt and crude oil shall be allowed to penetrate the subgrade surface.

Bitumen shall be heated to a temperature of 175oc and applied to the subgrade by a

suitable sprayer. Immediately following the application of bitumen, dry sand shall be

uniformly spread. Lining should be started 6 to 12 hours after spraying.

108

5.0 LAYING OF CONCRETE LINING

5.1 GENERAL

The lining shall consist of M-20 grade cement concrete. Ordinarily,

thickness of the slabs in the bed shall be 100mm and that on the sides 125 mm or as

otherwise prescribed in the drawings. The cement concrete slabs in the bed shall

rest on cement concrete bed sleepers (concrete grade M-15) 225 mm wide and 110 mm thick laid in –situ and those on the sides shall rest on precast cement concrete

blocks 225mm wide and 110mm thick (concrete grade M -15) cast in 600mm

lengths. The lining shall have longitudinal and transverse joints at convenient and

regular intervals as shown in the relevant drawings to avoid cracks due to volume

changes in concrete.

The lining shall normally be placed first on the bed and then on sides.

Where conditions require laying of lining on sides first , it shall be suitably supported

as per drawings.

5.2 CEMENT CONCRETE

The concrete lining slabs be cast in controlled concrete of grade M-20

conforming to IS -456 -2000 requirements.

5.3 SLUMP

For hand placing and for placing with light machines where concrete is

screeded from bottom to top of the slope, the consistency shall be such that the

concrete will barely stay on the slope. A slump of 60 to 70mm shall be generally

allowed. For heavier longitudinally operating slip –form machines, a slump of 50mm

shall be permitted. To have a close control of consistency and workability of the

concrete, the slumps of concrete shall not vary by more than 20mm which would,

otherwise, interfere with the progress and quality of the work.

5.4 AIR ENTRAINING ADMIXTURE

Air entraining agent may be used if specified to increase work ability, to

make concrete impervious and more durable and free from honey-combs and

109

bleeding. Air entraining admixture shall conform to IS: 9103-1999 (Amendments 2)

“specification for admixtures for concrete”.

5.5 LAYING ON SLEEPERS

In-situ sleepers in case of bed and precast on sides, should be

provided under the joints in proper position. The sleepers shall be laid in the bed and

on sides slopes centrally below the joints in slabs as this helps in having the sub

grade dressed perfectly. Trenches of the required size, both in the bed and sides

shall be dug to receive the sleepers. Care shall be taken that cavities left on either

side of the sleepers, laid in the trenches dug on the side slopes are properly filled

and compacted before laying on the concrete slabs.

Before laying cement concrete slabs, to ensure water tight joints, the

top of the sleepers both in bed and side slopes, shall be treated as per para 7.2.

5.6 LAYING OF SLABS

Manual concreting shall be done in alternate compartments with an

interval of atleast one day for setting and contraction .Slabs shall be so laid that

these shall abut against each other at the centre of the respective bed sleepers both

crosswise and longitudinally. Method of placing shall be such as to preclude

segregation. The concrete shall be placed and compacted in any case before setting

commences and shall not be subsequently disturbed.

5.7 MIXING

Concrete shall normally be mixed in a mechanical mixer. Mixing 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 the mixing be done for less

than two minutes.

5.8 TRANSPORTING

Concrete shall be handled from the place of mixing to the place of final

deposit as rapidly as practicable by methods which will prevent the segregation or

loss of any of the ingredients. If segregation does occur during transport, the

concrete shall be remixed before being placed.

110

During hot or cold weather, concrete shall be transported in deep

containers. The deep containers, on account of their lower ratio of surface area to

mass, reduce the rate of loss of water by evaporation during hot weather and loss of

heat during cold weather.

5.9 PLACING

Placing of concrete shall not be started until all form work, installation

of parts to be embedded and preparation of surfaces upon which concrete is to be

laid have been completed. All absorptive surfaces, against which concrete is to be

laid shall be moistened thoroughly so that moisture will not be withdrawn from freshly

placed concrete.

The surface, however, shall be free from standing water and mud and

1:3 cement slurry shall be spread over, the moist subgrade before placing concrete

to prevent absorption of water content from concrete, making it spongy.

In case filter material is to be provided over subgrade to take care of

differential hydro-static pressure and draw-down in canal, designs of coarse filter

material blanket immediately in contact with lining would be necessary. To make

such filter blanket effective and to prevent ingress of concrete into it, before

placement of concrete, tar-paper or burlap shall be placed over the filter blanket.

5.9.1 HAND PLACING

Hand placing of concrete shall normally be adopted where cheap

labour is available or where the quantity of concrete to be placed is small. The

concrete shall be dumped and spread on the sides and bottoms of the canals in

panels of sizes as prescribed in the relevant drawings with suitable joints in between.

Screed guides shall be laid on the subgrade and concrete shall be screeded up-to

the grade to proper thickness. To have the lining perfectly level, a plain wooden

template shall be moved over the slab and un-evenness removed.

Before laying the concrete, precast or cast in situ bed sleepers as

prescribed in paras 5.1 and 5.6 shall be provided under the joints to serve as

templates for accurate dressing of the subgrade and to reduce the seepage through

the joints. The joints shall be filled with preformed joint filler as shown in plate -5

111

The bays/panels should be formed by proper form – work of M.S.

channels laid all around the bay. The channels should be firmly spiked to the

subgrade so that no movement takes place at the time of concreting and vibration.

The depth of M.S. channels should correspond to the required thickness concrete

lining. The concrete should be dumped in the bay from bottom to top and then

spread all over the bay uniformly and to the required thickness guided by channels.

The spread concrete should then be compacted properly and thoroughly by means

of mechanical or screed vibrators. An improvised plate vibrator operated by high

horse power engine and a winch for moving the vibrator up the inclined slope should

be made use of for proper compaction. When width of panel is less i.e. upto 2m

manual operation of vibrators is possible and may be permitted. In no case the

concrete should be compacted by tamping. The compacted surface should be true to

the required side slope. Before re-using the channel forms, they should be

thoroughly cleaned and well oiled. Care should be taken, while placing and vibrating

the concrete that, the subgrade in the adjacent bays does not get spoiled.

5.9.2 MECHANICAL PLACING OF CONCRETE

5.9.2.1 RAIL GUIDED SLIP FORM

For placing of concrete in canal, longitudinally operated slip forms

supported on rails placed along the berms of the canal may be adopted, concrete

should be spread uniformly on the bed longitudinally and on the sides from bottom to

top.

5.9.2.2 MECHANICAL PAVER

In case of concreting by paver machine, the concrete is screeded in

transverse direction and from bottom to top on the sloping face of the canal.

Concrete should be spread uniformly on the bed longitudinally and on the sides from

bottom to top.

5.10 FINISHING

The surface of concrete finished against forms shall be smooth and

shall be free from projections, honey-combing and other objectionable defects,

immediately on the removal of forms, all unsightly ridges, or lips shall be removed

112

and undesirable local bulging on exposed surfaces shall be remedied by tooling and

rubbing. Repairs to concrete surfaces and additions, where required, shall be made

by cutting regular openings into the concrete and placing fresh concrete to the

required lines. The chipped openings shall be sharp and shall not be less than 70mm

in depth. The fresh concrete shall be reinforced with wire mesh extending to the full

depth of slab and chipped and trowelled to the surface of the openings. The mortar

shall be placed in layers not more than 20mm in thickness after being compacted

and each layer shall be compacted thoroughly. All exposed concrete surfaces shall

be cleaned of impurities, lumps of mortar or grout and unsightly stains.

The concrete should be finished to an even and smooth surface free

from pockets, voids or exposed aggregates. This should be obtained by careful use

of a long-handled steel trowel. Any remaining roughness or rough spots shall be

rendered smooth, without any time interval after laying the concrete, with cement

mortar of 1:3 proportions.

5.11 CURING

Subsequent to laying concrete lining and after a period of 12 hours, the

lining shall be cured for at least 28 days. On bed this may be done by constructing

150mm deep earthen bunds across the bed so that a small depth of water will stand

on the bed. The curing of side slopes may be done by constructing masonry drains

with weep holes or perforated pipes on the coping at the top of lining or by sprinklers.

5.12 TESTING

In order to test the effectiveness of vibration, permeability and strength

of concrete cores at suitable places from the sides as well as from the bed concrete

should be taken.

6.0 SURFACE DRAINAGE

The top of the side lining concrete should be keyed into the subgrade

both in cutting as well as banking by taking it horizontally for a width of about

550mm. This key would prevent direct entry of surface rain water behind the lining.

The top surface of the key should be finished with a downward slope of 1 in 10 or so

113

towards the canal. A day after completion of concreting of all panels between two

templates, concreting of key stab should be done.

Concurrently with the curing operation surface drainage arrangement

of the bank such as construction of keys, bank surface slope away from the lining

and construction of longitudinal drain on the outer edge shall be completed. This is

necessary to prevent surface and subgrade erosion and consequent damage to

lining.

7.0 JOINTS

7.1 EXPANSION JOINTS

The expansion joints shall not be provided except where structures

intercept the canal. The joint shall be 12mm wide to be back filled suitably, as per

drawing on Plate-6.

7.2 CONSTRUCTION/CONTRACTION JOINTS

Construction joints form a weak link in the lining and deterioration is

generally noticed at such joints. Besides joints are potential seepage points for the

canal water. As such, number of joints should be kept to the minimum and great care

should be taken to obtain well compacted and smooth concrete surface at joints. To

ensure a good surface the shuttering should be smooth, cleaned, well oiled and

rigidly fixed at site. Besides different mechanisms for compaction of concrete in

lining, tamping with iron bar near the joint surface gives better results.

To cater for initial shrinkage and cracks manual concreting should be

done in alternate panels or bays. The panel size for the bed and slope of the canal

should be adopted as given in the drawings. 25cm wide L.D.P.E. film of 150 micron

thickness should be placed on the top of sleepers, provided to support construction

joints. The top of film and side of panel should be applied with primer conforming to

IS 3384:1986 (First Revision) “specification for Bitumen primer for use in water

proofing & damp proofing”. This sheet acts as an interceptor for seepage through the

joint (refer Plate-5).

In case lining is laid by mechanical placing, PVC water stops shall be

placed at joints along with the concreting. The water stops in such a case should be

114

provided at a spacing not more than 4 metres centre to centre both ways (refer

Plate-9). Construction joints shall be placed at any location where it is suited as an

exigency to construction. The joint shall be provided with cement concrete sleeper

and sealing compound layer.

7.3 FILLER

Back filling of the grooves and top sealing of the joints shall be taken

up after curing period is over. In the meantime, the joints/grooves are liable to be

filled with earth, which will be difficult to be cleaned. It is, therefore, advisable to fill

these joints with coarse sand during the curing period. The same can be easily

blown out from the joints when required.

The grooves should be filled as soon as the concrete has become

sufficiently stiff to prevent appreciably distortion of groove shape or damage to the

concrete. The grooves should be clean and free from foreign substance when these

are filled with mastic filler or hot applied sealing compound.

Grooves and joints shall not be filled while it is raining or when there is

free water therein.

115

5. Specification of Protection work 1. Wire Crates

Generally size of wire crates shall be 4 ft. X4 feet (1.2m X 1.2 m). In shallow

situations size may be increased whereas in deep and inaccessible situations the

same may be decreased. Actual size of wire crates shall be as specified by the

Engineer-in- charge.

The crates shall be made from No. 6 or 8 or 10 S.W.G (4.75 or 4.00 or 3.25 mm.)

galvanised iron wire as specified by the Engineer-in-charge. Unless otherwise

specified, the mesh of the gauge or create shall be 6 inch X 6 inch (15 cm. X15 cm.)

or 10 inches X 3 inches (25 cm. X 75 cm.).

The netting shall be made by fixing a row of spikes on abeam at a spacing equal

to the mesh. The beam must be a little longer than the width of netting required. The

wire is to be cut to lengths about three times the length of the net required. Each

piece is bent at the middle round one of the spikes and the weaving commenced

from one corner. A double twist shall be given at each intersection.

The bottoms and two ends of the crate shall be made at one time. The other two sides shall be made separately and shall be secured to the bottom and the ends by twisting adjacent wire together.

This twisting shall be carefully done by means of a strong iron bar, five half turns being given to the bar at each splice.

2. Placing and closing Wherever possible, crates shall be placed in positionbefore filling with brickbats,

bricks, or boulder as the case may be. The top shall be made separately and shall be fixed in the same manner as the sides after the crate has been filled. Where it is not possible to construct wire crates in situ, tipping of the same shall be resorted to.

3. Filling of Materials.

a) Bricks and Brickbats.—Pucca third class bricks or pucca brickbats should be used. No kutcha or pilla bricks of bats shall be allowed to be used in filling. Jhama and over burnt bricks or brickbats shall be preferred.

(b) Boulders –boulders used for filling shall generally conform to specification No. 3.31. No dimension of boulders shall be less than 6 inches (15 cm.) No boulder shall weigh less than 40 lbs. (18 kgs.).

2. Boulders

Boulders shall be rounded or sub-angular stones that have originated in place or have been transported by running water or ice. They shall be sound, durable and free from laminations, soft spots, cracks and other defects.

116

Quality The minimum diameter, wherever specified, shall mean the least diameter of a

boulder across its mid -section. Generally, large size boulders with minimum diameter not less than 6 inches (15 cm.) shall be used in all boulder work except where otherwise specified in this book. In the case of hand-placed riprap or pitching, at least 50 percent of the surface shall be of boulders which in depth are equal to the specified thickness of riprap. The remaining boulders shall have minimum Weight not less than 40 Ibs. (18 kg). In the case of dumped riprap, boulder shall be reasonably well-graded in sizes ranging from 1/2 cu.ft. to 1/2 cu. yd. (0.014 to 0.38 cu. metres), with, a maximum of 25 per cent smaller than ½ cft. (0.014 cu, meters) and a minimum of 30 per cent larger than 3 cft. (0.084 cu. metres).

The boulders shall be slacked compactly on level ground in stacks not more than 3

ft. (0.9metre) in height or such other height as may be prescribed by the Executive

Engineer. The actual dimensions of stacks shall be measured and the total quantity

reduced by 1/7th to arrive at the net quantity for payment.

Filling to be hand packed

117

TENTATIVE QUANTITIES OF MAJOR ITEMS OF CIVIL WORK

1. Earth Work Excavation & Filling = 1.69 lacs cum

2. Concrete = 0.29lacs cum

3. Reinforcement of various sizes = 3633 MT

118

VOLUME II

SECTION - 11

DRAWINGS

&

SITE INVESTIGATION DATA

(Refer folder for drawing and Data)

119

Index

Sr. No. Description Page No.

1. Details of Plates, Drawing & Sketches 119-120

1.1 Details of Plates appended in Vol-I 120

1.2 Details of Drawing & Sketches appended in Vol-II 120

2. Site Investigation Data 121

120

1. DETAIL OF PLATES AND DRAWINGS

121

1.1. Details of plates appended in Volume-I

Sr. No. Drawing No. Description

1. Plate-1 Site plan

2. Plate-2 Quarry Sites

1.2. Details of Drawings and sketches Appended in Volume-II

Sr. No. Drawing No. Description

1. 25-SP-107 (Rev

No I)

Aqueduct Over Sukhral Khad RD 333m ± to 487m ± of Ravi Canal Concrete Outline (Preliminary)

2. 25-SP-108 (Rev

No I) Aqueduct Over Sukhral Khad RD 265.8m ± to 333m ± of Ravi Canal Concrete Outline (Preliminary)

3. 25-SP-109 (Rev

No I)

Aqueduct Over Sukhral Khad RD 487m ± to 588m ± of Ravi Canal Concrete Outline (Preliminary)

4. 25-SP-110 (Rev

No I)

Aqueduct for adjoining khad Sukhral Khad RD 588m ± to 714m± of Ravi Canal Concrete Outline (Preliminary)

5. 25-SP-111 (Rev

No I)

Aqueduct for adjoining khad of Sukhral Khad RD 714m± to 819m± of Ravi Canal Concrete Outline (Preliminary)

122

2. SITE INVESTIGATION DATA

(Refer Geotechnical investigation report along with bid document)

SHAHPURKANDI DAM PROJECT

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