Indian National Committee on Large Dams. Design and Construction Features of Selected Dams in India

of machinery). Matrix

concrete

was

punped

and spread

in

20 cm layers.

An

equal

quantity

of large

stones

were vibrated

into the

matrix.

Using Gabbro

with a

specificgravity

of

3.1,

the final

product

could

have

a

specific

gravity

2.7 to 2.9

(much

higher.

than

rhat

achieved in

mixed concrete

of

graded

aggregates).

As

a

digression

(and

once again in retrospect)

it is

observed

that

colcrete masonry

even

if it

used 35 to

40

percent

cement

paste (average

37.5

percent)

has an edge

(in

India)

over

Rubble

Concrete,

because

(i)

all

crush-

ing

plant

is done

away with

(if

natural

sand is avail-

able)

(and

it is mostly

so in India within

economic

leads

and at

less

cost than crushed

sand),

(r'i)

no batch-

ing and

mixing

plant

is required,

(fii)

no

vibration

is

required,

and

(fu)

is better done in shallow layers or

liftsof0.6m(2

f0 against

2m

and 2.5

m reducing

problems

of heat

of

hydration and

cost

of formwork.

This

notable contemprary achievement

in

West

Germany was

grasped

eagerly

and a fourth

alternative

of

rubble

concrete as at Oker

Dam was introduced

as

one

another

option

into

the tender

specification at

Koyna.

p-ercent

it

will still

be

paid

as

40

percent

rubble-though

the matrix

concrete

consumed

is more

than

6O

percent.

Rubble

price

is

much

cheaper

than

concrete

as ii

is not

Simultaneously

experiments

were started late

in

1955

and in

1956

on

rubble

concrete

with

local

materials and

local

conditions

(unmechanised).

Before any

conclusive

deductions

could

be

arrived

at

by

local

tests,

tenders were

received

and lowest

acceptable

tender

offered

a

rate

for

rubble

concrete

11

percent

cheaper

than

that

of

conventional

mixed

con-

crete.

Hand

placed

masonry

was

quoted

8

percent

lower

than

that of

rubble

concrete. ln the

given

site

conditions

of

(i)

Isolation,

(r'i)

Lack

of

natural

sand,

(iii)

Lack of skilled masons

;

and

(fu)

Lack of working

space,

and

because

rubble

concrete is

more

suscepti:

ble

of

quality

control

and more homogeneous

than

masonry,

and

lastly

having regard to the

speed

of

construction

required

to

meet

the target

date for

power

production, rubble

concrete

tender

was accepted.

Seetion

fV-Stud,ies

on ft,ahble Coimetete

4.1

Rubble Concrete

Studies

plant

of

the dam. Density

and

permeability

tests

were

conducted on

0.9

m

(3

ft) dia.

by

1.8

m

(6

f0

long

cores

taken

one from each

block.

In

view

of

the

size of rubble

as

large

as

40

cm

(16

in.),

it

was

considered necessary

to have

a

diameter

of

0.9

m

(3

ft)

atleast for the cores

to be

representative

specimens.

Immediately

after

the installation

of the

aggregate

a

and

sand

production

units,

it was decided to

supplement

the

test

blocks

using

graded

materials

produced by

the main

crushing

piant,

so

as to simulate

the

actual

material

of

which the dam

will

be

built.

The

concrete

as

produced

by

the

Winget

weigh

batching

and

mixing

plant

and

weighed

quantities

of rubble

were

used in

-building

the

test

blocks. Laying,

spreading,

vibration,

etc.,

in

the

construction

of these,blocks

simulated

those

io be

adopted

in the

construction

of

the

Koyna

Dam

proper. The

height of the test

blocks

in

this

case

was

iestiicted

to

3 ft

(approx.

1 m),

as

we

had

no

direct

compression

testing

machine

to accommodate

1-8 m

(6

ft)

high cylinders.

As we

had a

4

millior

p999d

direct

iompreJsion

testing

machine at Hirakud

which

could

take^0.9

m

(3

ft)'hfutr samples,

cores

were drilled

out

of

the test'

blockJ

and

were tested

to

failure.

The

matrix

concrete

for these

blocks were

designed

to

have

v-4t*-4

t27

PHOTO 4.1

:

Shape

of aggregates.

dia,

by

1.8 m

(6

ft)

high

cores

(7

No.

8).

On

0.9

m

(3

ft) high cores

(20

in number)

compression

test

could

also be

carried out

in

addition

to

permeability

and

density.

Simultaneously

with

the casting

of

these

rubble

concrete

test

blocks

specimens

of 15.1

cm

(6

in.) dia.

and

30 cm

(

12 in.)

high were

also cast from the matrix

concretes to correlate

the

properties

of the matrix

with

those

of

the resultant

material.

---Gbles

IV. I

to IV.

4

give

detailed

information ob-

tained

from

the test blocks-Photos

4.I

to

4.4 illustrate

the

adverse shape

factor

ofcrushed

basalt

coarse

aggre-

gates,

the

1.8 m

(6

f0 long

0.9

m

(3

ft) dia. first core,

0.9

m

(3

f0

high

cores before

and

after subjecting

them

to direct

unconfined

compression test

up

to

failure.

PHOTO

4.2

: 3

ft

diameter

6

ft

long

rubble concrete core.

128

PHOTO

4.3

:

3 ft

diameter

3

ft Iong rubble concrete core.

T1TITTT'':qF*=

R{E

PHOTO 4.4

: 3

ft

diameter 3

ft

long rubble concrete

core after

failure in a direct

compression test.

'-E+.-W

46EPP+1

\29

TABLE

IV. 1

Rubble

concrete

test

blocks:

particulars

of

casting

and

mix

dala.

in.)

Test

block

no.

Date

of

Iaying

Particulars

of fine

concrete

with

maximum

size

Unit

weight

(Pcf)

6 in.

x 12

in.

cvl.)

Percent

rubble

sunk

by

volume

Water-cement

Design-ceme@

ratio

(by

wt.)

c-onrent

Pcy-

(in.)

-

aft

o/o

28

strength

psr

'

(kg/cu

m)

2

3

4

Jan. 1956 0.50*

Feb.

1956

0.53

-do-

0.69

0.57

March

1956

0.51

43s

Q6o)

556

460

4ee

(300)

583

584

560

(336)

560

s00

(300)

4s0

(270)

400

(24)

450

0.570

0.625

0.554

0.62

0.69

0.775

0.67

159.5+*

161.9**

159.0**

160.8

159.0

156,5

155.2

r58.0

156.8

156.s

156.7

r57.0

2205***

3267***

2511***

3522***

4083***

4165+**

3134

2707

4315*

3145

27

30

2444

33.05

26.07

3t.47

37.8

33.9

39.2

40.7

39.5

37.8

39.8

35.6

t-

1-

l-

l+

3.5

2.5

3.0

3.5

3.3

3.9

3.0

3+

3

3g

3

2+

6

7

8

9

10

l1

t4

Jan.

1957

March

1957

April 1958

-do-

June

1960

.:y./C

plps

B

Surkhi re,placement

20

percenr

cement

by

**Theoretical

unit

weight.

*t*Strength

of

6

in.

cubes.

1

in.

:

2.54 cm.

weight

TABLE

W.2

Density

and

permeability

of

3

feet

diameter

rubble concrete

cores.

Test

block

no.

Percent

rubble

sunk

by

volume

Theoretical

density

lb/cu

ft

Density

of

rubble

concrete

Permeability

of

3

ft diameter

rubble

concrete

cores

Actual

cores

lb/cu

ft

(t/cu

m)

Rate

of PeiEolationt

Permeaoitr-

ty coeffici-

ent,

K,

10-12 ft/sec

Age at

test,

days

Gal/Min/sq

ft

Litres/Min/sq

m

(Axts-s;

(nxi6-a;'

2

3

4

5

6

7

8

9

l0

1l

33.05

26.06

31.47

37.8

33.9

39.2

40.7

39.5

37.8

39.8

t65.9

t66.3

t69.1

r74.6

r6i.9

166.2

r68.6

168.3

t67.3

168.3

167.e

(2.68)

17r.6

(2.7s)

rr2.0

(2.7s)

172.2

(2.76)

167.e

Q.eg

16e.0

(2.70)

166.9

(2.67)

167.2

(2.7e)

B

6

26

l0

l1

8

79

81

r05

60

A

555

12

534

53

516

20

225

28

146

15

155

158

150

163

55

2r0

50

120

2t9

96s

360

515

270

981

rOt4

1306

737

*Percolation

test

done

at 150

p.s.i.

or

10.5 kg/cmz head.

I

lb/cu

ft

:

16.018

kg/cu

m,

I ft:0.3048 m.

130

TABLE

IV.3

Strcngth of3

ft

rubble

concrete

cores.

(f)

all aggregates

at

Oker

whereas

all

aggregates

ones.

are

natural

aggregates

at

Koyna

are crushed

Tcst

block

core no.

Age

days

Compressive

srrength

o.s.i.

(kg/sq

cm)

Actual

(ii)

Deccal

trap

on-

crushing

yierds

elongated

and

flaky

pieces

with

an

advirie

shape

f;;i;..

4.3

Density

at

Koyna.

4.4

Permeability

rol2

t014

lrll

n12

r0/r

t03

n13

tt

l4

96

87

E7

173

t73

t64

164

3032(217)

3280(23r)

3525(248',)

3086(217)

3737(263)

3157(243':

343t(24tI

3792(26t)

2433

(t7r)

2632

(r9s)

2829

(19e)

2453

(L7Z)

2997

(zrt)

277s

(t9s)

274s

(te3)

3032

(213)

*Core

L/D

ranged

frcm

0.90

to 0.92.

TABLE

IV.4

Rubble

concrete

strength

data

converted

to

6

in.

x 12 in.cyl.

strength.

Strength

of

3

ft

core

(Col.

4

Table

lV.3)

converted*

to size

6 in.

x

12 in.

cyl.

strength

p.s.i. (kg/sq

cm)

Individual

Average

(A)

Strength

of

Strength

(A)

finc concrete

expressed as

6

in.

X

l2

in,

percentage

of

cyl.

(B)

le60J

32osl

3440.l

zessl

36451

3380J

3083(217)

32t3i226)

35t2(2471

3520(247)

3353(236)

2704(reO)

38e9(274)

36t3(2s4)

92.1

It8.6

90.1

97.5

33{s}

36e5J

+Conversion

factor

0.822,

I in.

:

2.54

cm,l

fr:0.3040

m

4.2

Sinking

Irrespective

of

cement

content

in

the matrix

con-

t3l

-*Fd

T

I

:

\l

I

{_

I

i

The

core

with

ossembly

,A,ppendix

I

indicates

10.64 k-eicm2

(152

p.s.i.)

tension

at

the

periphery

of the

hole.

Possibility

of minor

cracks

appearing

in

the

surface

of

the

bore-hole

are

great

by

adopting this

procedure

of

test

(in

case

the

concrete

is

not

sufficiently

strong at

the age

of

test).

Further,

the

possibility

of one

40

cm

(16

in.) stone

embedded

between

the hole

and outer

surface,

pre-

senting

a continuous line of contact

from

the

hole

to

the

outer

surflace

[41.7

cm

(16]

in.)

apartl

makes

this

method

of

testing

unduly severe

and

unrealistic,

because,

in

any

design of

dam,

the

water

face

will

never

be

allowed to

be

under such tension

under

full

reservoir

condition;

nor can there be

such continuous

line

of

contact

from

water face

to the

air face. But it-

nearly

simulates

the actual

conditions of

stress

and

jointing

in

the

dam,

though it

exaggerates

thern

too

much.

This

procedure

of test

being very much

simp-

ler

and harsher

enables

a

clear and visible

evaluation

of

all

the

properties

of

the material

such

as

density,

permeability

and strength

determined on

the

same

speclmen

or

core.

The

Materials

Laboratory

of the

Facult_v of

En-qineering,

University

of

Rome,

adopts

a seemingly

similar

procedure

but the

radial

flow

is

from out-

side

in-on

small

size

test specimens. In

our case a

bulky

fabricate

of

jacket

was

needed.

The

rate

of

percolation

expressed as

the conven-

tional

'K'

and in

gal/min/sq

ft

of

bore

area

is

given

r32

In

situ

percololion

test

opporolus

ossembfy

(detoilsl

FIGURE

4.1

: In situ

percolation

test

apparatus

assembly

(Details).

in Table

IV.2.

The

formulae

of

packer

test

for

bore

holes

are not quite

adoptable,

because

their best

validity

is

when

thickness

of

stratum

tested

is

at-

least

five

times

the length

of

the

hole

tested

and

that

too below

ground

water-table.

There

have

been

no

universa-lly

accepted values

for

classifying-concrete

on

the basis

of

permeability

coefficient.

The

Italian

Engineers

classify

conventional

corrcrete

with

a

,K'

rvith

an increase

in

the

maximum

size aggregate

in

conventional

concrete

as

indicated

in

thC

Boulder

Canyon

Project

reports.

If rubble

concrete can

be

considered

to be

concrete

with

gap

graded

400

mm

(16

in.) maximum

size

aggregara

fu is

natural

to

expect

'K'

values

higher

than

conventional

150

mm

(9

tn.)

aggregate

concrete.

Criteria

for

judgingthe

suita-

bility

of

concrete

either

for

the interior

o1 the exterior

.

l.

Steel

wosher

Z,Rubber

wosher

] ferforoted.

pressure

pipe

!.Perforoted

spocer

prp'e'

S.Bottom plug

kg/cm2

(100

to

150

p.s.i.)

head rubble

concrete

can

be

safely

rated

as

impervious

requiring

no

post-construc-

tion treatment.

4.5 Strength

and

Homogeneity

After

the

density

and

percolation

tests,

several of

these

0.9 m

(3

f0 diameter

cores

were tested

in

com-

pression

at

Hirakud.

Simultaneously

companion

matrix

concrete

cylinders 15

cm

x

30

cm

(6

in.

x

12

in.)

were

also

crushed. Observations made during

crushing

of

rubble concrete

cores

revealed that

invari-

ably

the development

of

the

first

crack

had

been

instantaneous

as

well

as

simultaneous both

in

the

rubble

and

the

concrete

indicating

the

homogeneity

of the

combined

mass.

lt

is

probable

that

the internal

compressive

stresses

built

up within

the

rock

mass

could

be

2-3 times

more

than

that of the

matrix

con-

crete

when it

is

presumed

that rubble

concrete

as

a

mass

would

have

uniform

deformation; this

assump-

tion is

based

on

the

relative

differences in the

modulus

of elasticity

of

the

two

components.

The

surface

of

the

cores

indicate a fullycompacted mass

and absence

of air

voids

or segregated

zone indicate

good

bond

between

the concrete

and the

rubble

(Photos

4.3

and

4.4).

The

large size

cores

yielded

strength

of

over

210

kg/sq

cm

(3,000 p.s.i.)

at ages

of

90

days

and

over

(Table

lV.4) even

when

the

cement

content

of

the matrix

poncrete

was

270 kg/cu

m

(450

pcy)

[280

pcy

or

168

kg/cu

m

in

rubble

concretel

or 24O

kglcu

h

i+OO

pcy)

[240

pcy

or

144 kg/cu m in

rubble con-

crete].

The strength

data

of

the

companion

15

cm

x

30

cm

(6

in. x

12 in.) cylinders

when

corrected

for

the

sizsand

Li

D

ratio to

equate

with

the

large size

core,

by

applying

the standard

factors

revealed

that

the

strength

of the

rubble

concrete

is

reflected

to a

large

extent

directly

by

the strength of

the

matrix

concrete

in

it. For design

and

control

purposes,

tests

on standard

15 cm

x 30

cm

(6

in. x

12 in.\

cylinders

of

matrix

concrete

can

by

proper

interpretation,

indi-

cate

the

potentia!

strength

of

rubble

concrete.

4.6 Field

Performance

A

lava

flow

free

from

secondary deposits of

zeolites,

chalcedony,

etc.,

was selected for

the

quarry,

at a

minimum

tead

of

about

0.8 km to 1.2 km

$

mite to

f

mile)

at

an elevation

above

FRL

The

properties

of

the

quarry

rock

are

tabulated

irr Table IV.4

(a).

An

idea

of

uniformity

in

the

gradation

of the

aggregates

produced

from

season

to season

can

be

had

from

lable

tV.4

(.b).

Two

rodmills each

of

45

tons

capacity

per

hour

produce by

wet

process

the

required

grade

of

sand.

Afcer

eliminating

the

excessive fines through the

static

cone

arrangement,

by

continuous trials and

testing,

a

good

measure

of success was

achieved in

producing well-graded

sand

meeting

the

general

requirementsof

the

work.

The

average

grading

of

the

sand

produced

is

given

in Table

tV.4

(c).

Jo,

place

_c_oncrete

at

65' F

or less

the

aggregates

and

the

rubble

are

precooled

with

chilled waier

white

as

the

rubble were

conveyed

by

silo buses

to

load

the

4.56 cu

m

(6

cu

yd)

buckets

of two cable

cranes

[span

731.5

m

(2400

ft)] 15

T. hook load Tabte

rv.4

(d).

Mix No.

1 was

usod

hardly

for abour

0.035

M

(19

M

cu

ft) up

to

El.

2150-60

was

placed

with

270

kg/cu m

(450

pcy)

concrete.

lnvarlably

above

El. 2,150

the

240

kg/cu

m

(400

pcy)

concrete was

used. Though

the preliminary

evaluation

of rubble

concrete

had

shown

that as

far as

strength-curn-

permeability

was

considered

even

240 kg/cu

m

(400

pcy)

concrete

could

have

been

adopted

over

elevation

1900.

Since

the rubble

concrete

construction is

being

practised

in

India

for

the first

time, the reduc-

tion in

cement

content

was

made continuously

and

gradually.

Water-cement

ratio

for the interior

con-

crete

with

270

kg/cu

m

(450

pcy)

matrix

concrere

is

0.69 weight

and

with

240 kg/cu

m

(400

pcy)

matrix

concrete it

is 0.75.

For

the upstream 1.8

m

(6

fr) instead of

the

rubble-

concrete

a richer

and

conventional concrete with

7.5

cm

(3

in.) maximum

size

was used

which

had

269

kg/cu

m

(445

pcy)

cement

and

156

kg/cu

m

(260

pcy)

water; similar

concrete was

placed

in the

downstream

in

the

overflow

monoliths.

The

placement

of

rubble

concrete consisted

of

spreading the

plastic

air-entrained

matrix concrete

to

23

cm

(9

in.) thick

layer

and

closely

packing

the

rubble

over

this and vibrating

the whole layer with

l0 cm

(4

in.)

dia.

electrical vibrators

(frequency

of

7000-

9000

vibrations

per

minute)

held

by

two men

standing

on

the rubble.

ln

each

cycle

a strip of 6

to 8

m

(20-

25 ft)

parallel

to

axis

was

taken

(Photo

4.5).

Rubble

after it

was

unloaded

as a

dump

over

the

plastic

concrete

was

spread

manually.

Trials

made

to

spread

the

concrete and

then

the rqbble

by

a small

dozer

revealed

that

the

concrete

got partially

compac-

ted

and

that much

less

quantity

of

rubble

got

sunk

with

all

the best

of efforts

in vibration.

The

prepara-

tion of the

surface

of rubble concrete

for

the

---

ql.'|dta,ft{2

133

TABLE

IV.4

(a)

Rock

Coarse

a-egregate

Manufactured

sand

Density

Pcf.

(t/cu

m)

Crushing

strength

cores

of

LID:2

p.s.i.

(kg/sq

cni)

B.S.

crushing

percent

loss

Los-

Angeles

-

abrasion

percent

wear

Sp.

Gr.

Absorp-

S.S. D.

tion

percent

Sp.

Gr.

Abs-

S.S.D.

orption

percent

NarSOa

soundness

loss

percent

(5

cycles)

183-186

1000

to

2000

Q.23

(700-1400)

2.e8)

2.93

20

23

1.5

3.5

2.87

7.9

2.9

TABLE

rV.4

(b)

Size

Season

No.

of

tests

Percent

retained

on

A.S.T.M:

sieves

lf in.

314

in.

3/8

in.

3116

in.

-3l

16 in.

Coarse

aggregate

(3/4

in.

to

l$

in.)

20-40

mm

1958-59

r959-60

1960-6r

t96t-62

1958-59

1959-60

1960-61

r96t-62

89.3

87.2

89.1

83.2

18.5

18.6

t8.2

18.0

4.8

7.6

6.4

6.0

s0.7

54.7

53.7

54.0

1.6

1.9

1.5

1.4

22.5

16.8

20.1

20.r

231

260

268

241

247

250

273

24r

2.1

1.6

2.2

8.0

2.2

1.7

0.8

8.3

9.9

8.0

7.0

TABLE

IV.4

(c)

Item

Season

No.

of

tests

Cumulative

percent

retained

on

A.S.T.M.

sieves

t6

30

50

100

Manufactured

Rod-

mill

sand

:

Wet

process

1958-59

1959-60

r960-61

196t-62

17.9

18.7

19.7

20.5

38.0

39.5

4r.7

42.9

57.2

57.6

63.5

63.4

71.9

71.5

80.6

77.6

83.8

84.8

87.4

86.9

848

858

7t0

446

2.1

0.9

1.0

1.5

r34

E,:+TIlt{fF$fiU*

PHOTO

4.5:

Rubble

concrete construction.

TABLE

rv.4(d)

Typical

mixes

for'Interior'

or

'Matrix

Concretet

Max. size of

Aggregate

:

14 in.

,",r".frtT,?_i +

TABLE

IV.s

Average

physical

characteristics

of cement.

Mix

No.

Cement

Water Sand%

Rodmill

pcy/kg

pcy

4bs.

sand

PcY

cu m

Vol.

Coarse

Aggre-

gate

pcy

(+

3il6

in.)

I

in.

Season

I

percent

Source Fineness

(BIaine)

gm/sq

crn

Compressive

strength

data

No. of 7-day

Standard

Coeffi-

tests strength

deviation

cient

of

psi

variat-

ron

percent

I

2

3

A

560(336)

s0o(3oo)

4so(27o)

400(240)

300

310

300

38

40

4l

43

1330

t3t2

1405

1495

2000

202s

2020

1975

I in.

:

2.54 cm.

;

I

pcy

:

0.59 kg/cu m

available

for

placement.

1957-58

I 958-59

1959-60

1960-61

t96t-62

2676

326

3017

81

3190

189

3098

I I5

A

B

A

B

A

B

A

B

A

B

35

3256

70

3237

126

3248

r27

3s23

425

13

414 t3

4ts

13

650

l8

288 l0

449

14

452

13

463

13

3r0 l0

570

ls

2939

3t4l

3518

173

3563

r42

3372

3402

3229

3744

I

p.s.i.

:70.31gm/sq

cm

:

0.07031

kg/sq

cm.

-

-dta'?'+*4

135

Season

Source c3s

c2s

TABLE

IV.6

Average

compound

comppsition

(percent).

4.7

Strength

and

Thermal

properties

of

Concrete

Cement:

Ordinary

portland

cement

conforming

to

I.s.

: 269'1958 was

received

from

two separate

facto-ries

when

it

was

found

that

cement

cannot

be had

from

one single

factory.-{n

abstract

of

the

average

proper-

ties is

given

in Tables

lv.5

to lv.g

to

iicicate

ttre

uniformity

or fluctuations

from

source

and

period.

Cement

from

source B

yielded

higher

strength

at

earlier

ages.

The

cements

are

more

akin to U.S. type

II

except

for

the

C3A

and

are

expected

to

yield

beirer

long

range

strengths.

4.8

Strength

of Concrete-Laboratory

Series

i

To

facilitate design

and

adjustment

of

concrete

mixes

for

the

dam

and

appurtenant works,

each

season

several

water-cement

ratio

strength

series

is run

from

the

material

actually

produced

for

the works.

The

mixes

are

designed

on solid

volume

basis

as

per

ACI

6135.

The average

strength

obtained

with

the two

-

sources

are

given

for

the

period

1958

to

1962 in

Tables

lV.7 and

IV.8.

c3A C4AF

1957-58

1958-s9

l9s9-60

1960-6r

r96t-62

8

9

l0

9

8

7

8

r2

il

13

i0

r3

t4

l2

t2

14

i2

A3930

84526

A3832

B3933

A4924

84424

A1427

84326

A3336

B413!

Since

most of

the

rubble concrete

placed

is

with

270

kglcu

m

(450 pcy)

and

to

a

lesser

extent

with

300

kg/cu

m

(500 pcy)

only those

mixes

are taken

up

for

discussion

regarding

the

performance

either separa-

tely

or as

in rubble

concrete.

TABLE

IV.7

Compressive

strength

of air-entrained concrete.

(Laboratory

series

-Source

A cement)

Max.

size of aggregate-l*

in.

Test

specimen-6

in.

x 12 in. cylinder

Water-310-320

pcy

Slump-4

in. Air.

4

percent

C;cment, Pcy

WC

bv

wt.

400

o.77

4_so

0.6e

500

0.62

560

0.57

600

0.s3

400

0.77

450

0.69

500

0.62

560

600

0.57 0.53

Season

Age

days

Strength,

p.s.i.

Strength,

percent

1958-59

s2

r00

r53

7

28

90

700

r

350

r990

500

900

r600

550

1200

2050

2E50

3000

550

1200

2050

2322

2700

877

I

730

2650

600

I 190

2060

750

|

560

2700

3300

3550

750

1560

2700

3173

3200

1r06

2000

30r

0

800

1600

2520

950

1960

3340

3750

4050

950

1960

3340

38

t2

4000

1523

2280

'35r0

r050

2050

2930

1220

2490

3840

4260

4600

t220

2490

3840

4492

4650

1638

2650

3920

1300

2500

33r0

I

450

2870

4250

4850

5050

1450

2870

4250

4627

5100

52

100

147

55

100

178

46

r00

t7l

237

2s0

46

100

r52

194

225

50

100

160

48

100

173

212

228

48

100

152

2lr

20s

58

100

150

50

100

r58

48

r00

t7l

r9l

207

49

r00

152

195

204

67

r00

ls4

50

r00

r43

49

I00

r54

17s

185

50

100

rs4

r80

187

62

100

148

52

100

t32

50

100

148

159

176

50

100

150

t58

178

1

I

1959-60 28

90

7

28

1960-61

90

180

365

7

28

l96t-62

90

180

365

I

in.

:

2.54cm

;

I

pcy

:

0.59kg/cu m

;

I

p.s.i.

:

7O.31

gm/sqcm

r36

ji;

;:.'.L...=5i#'

Indian National Committee on Large Dams. Design and Construction Features of Selected Dams in India

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