1. IRC : 14-1977
RECOMMENDED PRACTICE
FOR
2 CM THICK BITUMEN AND
TAR CARPETS
(SECOND REVISION)
THE INDIAN ROADS CONGRESS
1988

2. JRC : 14-1977
RECOMMENDED PRACTICE
FOR
2 CM THICK BITUMEN AND
TAR CARPETS
(SECOND REVISION)
Published by
THE INDIAN ROADS CONGRESS
Jauinagar House, Sbahjabao Road,
New Delhi-110 011
1988
Price Rs 24/[PJus poataae & packina)

3. IRC : 14-1977
First published in 1963
First Revision October, 1970
Second Revision July, 1977
Reprinted: February, t987
(Incorporates amended sieve sizes)
Reprinted : August, 1988
Reprinted : February, 2000
[Rights of Publication tmd of Translation ar1 reHrYed)
Printed at DEE KAY PRINTERS, New Delhi-ll0015
(500 copies)

4. me: I4-J9n
RECOMMENDED
PRACTICE FOR 2 CM THICK BITUMEN
Al'D TAR CARPETS
INTRODUCTION
This Standard was originally printed in 1963. The revised
standard which is in metric tJnits after being approved by tne
Bituminous Pavements Committee was processed by the Specifications & Standards Committee and then approved by the Executive
Committee before it was approved by the Council of the Indian
Roads Congress in their meeting held at Darjeeling on the 5th and
6th April, 1970 for being issued as the finalised standard of the
Indian Roads Congress.
The present revised standard besides containing a few minor
amendments approved by the Bituminous Pavements Committee
also contains revised tolerances for surface evenness as approved
by the Council of the 1ndian Roads Congress in their 87th meeting
held at Madras on the 27th August 1976 and incorporated in the
lRC Special Publication 16 ..Surface Evenness of Highway Pavements" .
SCOPE
Thjs is a recommended practice for laying 2 em thick
bitumen and ta r carpel s. The type and grade of binder is left to the
discretion of the Engineer-in-charge, so a s to tc iu conformity with
cl imatic, traffic ar.d terrain condilio ns and based on past successful
practices.
A.
2 CM THICK BITUMEN CARPET
A .l. Materials
A .1.1. Binder : The bir.dcr shall be one of the following :
(i}
a straight run bitumen o f suitable penetration grade
compl)ing with IS: 73-1961 ;
(ii) a cutback bitumen of suitable viscosity complying with
IS: 217-1961 or IS: 454- 1961 or other approved
cutback.
A .1.1. Coarse a~gregates : The aggregates shall consist of
angular fragments and te clean, hard , tough, durable and of
uniform quality throughout . They shall be crushed rock, gravel,
river shingle or slag and should be free of elongated or flaky pieces,
1

5. IRC : 14-1977
soft and disintegrated material, vegetable or other deleterious
matter. The aggregates shall also satisfy the following properties:
1
Property
l.
Abrasion value, using Los Angeles
machine
Value
max. 35"o
I
Metho d of test
IS: 2386 (Pan IV)
or
2.
3.
4.
S.
6.
Aggregate impact value
Flakiness index
Stripping value
Water absorption (except in case of slags)
Soundness: Loss with sod1um sulphate5 cycles (m case of slag only)
Unit weight or bulk dens1ty
(in case of slag only)
max
max.
max.
max
30%
-do30% IS: 2336 (Part I)
25% IS: 6Z4 1
2% IS: 2386 (Part HI)
•
mlX. t:Z 0~ IS: 2386 ( Part V)
min. 1120 leg IS: 2386{Part Ill)
per m"~
Uncrusbed and rounded river gravel or shingle can also be
used but the quantity of binder would be different tn their ca:;e
from that given under para A.2. Where such rounded aggregates
are used, it may be necessary to add sufficient quantity of coars~
sand and an appropriate quantity of bot bitumen to make the
mixture suitable, for wbtch purpose such a mix will h:1ve to be
designed for binder content depending on individual cases.
A.I.3. Fine aggregates or sand : The fine aggregates or
sand shall consist of clean, hard, durable, uncoated, coarse dry
particles, and be free from injurious amounts of dust, soft or flaky
particles or organic matter or other deleterious substances.
A.2.
Quantities of Materials Requjred
A.2.1.
A.2.1.1.
Aggregates
For carpet
(a) Coarse aggregates-13.2 mm size;
passing IS 22.4 rom square mesh ,
retained on IS I 1.2 mm square
mesh
(b) Coarse aggregates-11.2 mm size;
passing IS 13.2 mm square mesh.
retained on IS 5.6 mm square
mesh
Per 10m 2 of
road surface
0.18m"'
0.09 m3
0.21
2
m3

6. IRC: 14-1977
A.2.1.2.
For seal coat
(a) Low rainfa/f areas (undeJ 150 em
per year)
Medium coarse
sand
(fineness
modulus of more tlian 2.5) or fine
grit passing lS Sieve No. 1.70 mm
and retained on IS Sieve No. 180
microns
0.06 m 1
(b) *High rainfall areas (over 150 em
per year)
D1l!?- size;
passing IS 11.2 mm square mesb,
Coarse
agg:regates-6.7
retained on
mesh
A.2.2.
lS
Sieve
2.8
0.09
m'
mm
Binder
Per 10m2 of
road surface
A.2.2.1.
(a) On
For tack coat
a
water-bound
macadam
7.3 to 9.8 kg
(b) On an existing black top surface
4.9 to 7.3 kg
surface
Note . For emulsions complying with IS: 3117-1965, the same
quantities as given above may be used. · In case the existing black top surface .is extremely rich in binder, or fatty
the tack coat can be eliminated in hot climatic regions
at the discretion of the Engineer-in-charge if a good bond
between the existing surface and the superimposed layer
can be ensured.
A.2.2.2.
For premixing
{a) For 13.2 mm size coarse aggregates
(b) For 11.2 mm size coarse aggregates
9.5 kg@ 52 kg per m3
5.1 kg@ 56 kg per ml
*In ease emulsions are used, the quantily reqai.rcd will be 50 per cent of
what is indicated.
3

7. •
me:
14-1977
A.2.2.3. For seal coat
{a) Low rainfall sreas {under 150 em
per year)
{b) *High rainfall areas (over 150 em
per year)
A.3.
6.8 kg
9.8 kg
Construct.i011
A.3.1. Preparation of base : Before the carpet is applied to
the existing base, the road must be free from dust or caked mud.
Where the existing base is potholed or rutted, these irregularities
must be corrected with premixed chippings or coated, macadam,
depending upon the depth of the pothole, laid after applying a tack
coat of binder and well rammed. thereafter. Where the existing
base is extremely porous and absorptive, a suitable primer (vide
I.R .C. Tentative Specification for Priming of Base Course with
Bituminous Primers) shaH be applied. The surfac~ should be
cleaned by:
(a)
removing caked earth
wire brushes,
and other foreign matter with
(b) sweeping with brooms, and
(c) finally dusting with sacks.
A.3.2. Tack coat : The binder s hould be heated, wherever
required, to the appropriate temperature as indicated by the manu·
facturers and applied to the base at the rate specified in para A.2.2.
It is best to use a sprayer. The binder should be evenly brushed, if
need be.
The tack coat should be applied just ahead of the spreading
of the premix.
A.3.3. Preparation of premix : Mechanical mixer should be
preferred. When only improvised hand mixing drums are available
for premixing, place 0.028 m 3 of 13.2 mm chippings and 0.014m'l
of 11.2 mm cbippings in the mixing drum and mix dry thoroughly.
Where straight-run bitumen is used, the aggregates should be suit·
ably heated prior to the adding of bitumen.
Add 2.24 kg of the binder, as per quantities given in para
A.2 2.2, heated where required. to a temperature suitable to the
*
In case emulsions are used , quantity required wlU be 50 per cent of
what is indicated.
4

8. IRC: 14-1971
grade of bitumen used, and mix until the chippings are thoroughly
coated with the binder.
Empty the premix on to stretchers or wheel barrows and
carry to site.
The quantities _ cbippings and binder per batch as given may
of
be proportionately increased if proper coating is possible in one
operation.
A.3.4. Spreading of premix : Immediately after applying tbe
tack coat, spread the premix with rakes to the desired thickness and
camber, or distribute evenly by means of a drag spreader. Cbeck
camber by means of a camber board and ev.en out inequalities.
A.3.5. Rolling : As soon as sufficient length, say 15 metres,
of the_ premix has been laid, rolling should commence with smooth
wheeled rollers (6 to 9 tonnes) or pneumatic tyred rollers. Rolling
should commence at the edges and progress towards the centre
longitudinally except in the case of superelevated sections where
this should commence at the inner edge and proceed towards the
outer edge of the curve.
Wben the roller has passed once over the whole area, any high
spots or depressions which become apparent should be corrected
by removing or adding premixed cbippings. When this. has been
done, roll to comapaction. Avoid excessive rolling as this serves no
useful purpose and may spoil the carpet.
Moisten the roller wheels to prevent
adhering to the wheels and being picked up.
the
premix
from
A.3.6. Application of seal coat : Jn low rainfall areas, i.e.
those having rainfall under 150 em per year, a premixed sandseal coat mixed preferably in a mechanical mixer after heating
the sand, should be applied immediately after laying the carpet and
rolled. Materials required for this seal coat are· given in paras
A.2.1.2. and A.2.2.3.
Jn high rainfall areas, i.e., those having rainfall over ISO. em
per year, a liquid seal coat preferably with cbippin~ (though
coarse sand can be used), should be applied after laying the
carpet. The binder, heated wherever required to the permitted
temperature, should oo applied to the cleaned . sorface, blinded
with chippings and rolled.
Materials required are given in paras A.2. 1.2. and A.2.2.3.
5

9. lRC: 14-1971
A ..3. 7. Surface finish : The finished surface shall be uniform
and conform to the lines, grades and typical cross-sections specified.
When tested with a 3 metre straight edge, the longitudinal profile of
the finished surface shall have no undulation greater than 10 mm,
and in any 300 metre length the number of undulations of 6 mm
size shall not exceed 30. The cross profile, when checked with a
camber template, shall not show a variation of more than 6 mm
from the specified profileThe checking of longitudinal and transverse profile shall be
canjed out in accordance with the methods and procedures described in IRC Special Publication 11 "Handbook of Quality Control
for Construction of Roads and Runways".
A.4. Opening to Traffic
Traffic may be allowed on tbe road preferably 24 hours after
providing the seal coat. This should be considered the minimum
period when the binder 11sed is a cutback or emulsion.
B.
B:t .
2 CM THICK TAR CARPET
M.terials
B. I. 1. Binder : The binder sba U be a road tar of grade
R .T 3 or R T-4 (No. IS: 21 5- 1961).
B-1-2. Coarse aggregates: The aggregates shall consist of
angular fragments and be clean, bard, tough, durable and of uniform quality throughout. They shall be crushed rock, gravel, .river
shingle or slag and should be free of elongated or flaky pieces, soft
and disintegrated material. and vegetable or other deleterious
matter. The aggregates shall also. sat•sfy the following properties :
I
Pro perty
Value
----------------------------------~max. 35%
1. Abrasio n value, using Los Angeles ·
j Method of test
IS: 2386 (Part IV)
machine
or
Aggregate impact value
2. Falkiness index
3. Stripping value
4. Water absorption {except in case of
slags)
s. So undness : Loss with sodium sulphate
-S cycles (in ca$e of slag only)
6. Unit weight o r bulk density
(in case of slag only)
6
ffi3X.
30%
max. 30%
max. 25%
max. 2%
IS : 2386 (Part IV)
JS : 2386 (Part I)
IS : 6241
IS : 2386 (Part Ill)
max. J2o/o
IS : 2386 (Part V)
min. 1120 kg IS: 2386 [Part III)
per m3

10. m.c:
14-1977
B .J .3. Fine aggregate or sand : As in para A.[ .J.
B.2. Quantities of Materials Required
B.2.l. Aggregates
B.2 . 1. 1. For carpet
(a) Coarse aggregates 13.2 mm size
passing IS 22.4 rom square mesh
and retained on
JS 11.2 mm
square mesh
(b) Coarse aggregates I 1.2 mm size
passing IS
L.3.2
mm square
mesh and retained on lS 5.6
mro square mesh
Per 10 m 1
of ruau surface
o.l8 m3
0.09 m 3
0.27 m3
B.2. 1.2.
For seal coat
Per 10m2
of road
surface
Medium coarse sand or fine grit
(passing on lS Sieve No. 1.70 mm
and retained on lS Sieve No.
180 microns)
8.2.2. Binder
(a) Fot· priming coat (on water~
bound macadam surface}
(b) For tack coat (on an
existing black-top surface)
12.2 to
14.7 kg
7.3 to
9.8· kg
9.8 kg
{c) For seal coat
(d) For premixing
B.3.
0.060 m 3
19.7 kg
@72 kg per m3
Construction
B.3.1. P reparation of base: As in para A.3. 1.
B.3.2. Tack coat : Tbe binder should be heated to 105° to
115o C and should be applied at tbe rates specified in para 8 .2.2.
7

11. IRC: 14-1977
It is best to use a sprayer.
The binder should be evenly brushed,
if need be.
The tack coat should be applied just ahead of the spreading of
the mix.
B.3.3. Preparation of premix : Mechanical mixers should
be preferred. When only improvised hand rruxmg d rums are
available for premixing, place 0 .028 m 3 of 13.2 mm chippings and
0.014 m3 of 11.2 mm chippings in the mixing drum and mix thoroughly dry.
Add 3 kg of road lar heated to l05° to 11 5o C and
mix until chippings, preheated if necessary, are thoroughly coated
with the binder.
Empty tbe premix on to st retchers or wheel barrows and carry
to site.
The quanti ties of chippings and hinder per batch may be p roportionately increa~cd if prorer coating is possible in one operation.
B.3.4.
Sprcadjog premix : As
B.3.5.
Rolling :
As in para
10
para A.3.4.
A.J.s:
B.3.6. Application of seal coat : Immediately after laying
the carpet, the seal coat should be applied in the m anner detailed
below:
Road ta r IS grade R .T .3, heated to 105° C should be sprayed
evenly at 9.8 kg per 10 sq. m . and then it sbould be blinded evenly
with med ium coarse dry sand as fine grit at the rate of 0.06 m3
per 10 m1 .
B.3.7.
B.4.
S urface finish:
As in para A.3.7.
Opening to Traffic
Traffic may be allowed on the road 24 bows after providing
the seal coat.
8