IS : 4031 ( Part 12 ) - 1988

( Reaffirmed 1995 )
Indian Standard
METHODSOFPHYSICALTESTSFOR
HYDRAULICCEMENT
PART 12 DETERMINATION OF AIR CONTENT OF
HYDRAULIC CEMENT MORTAR

( First Revision )
First Reprint MARCH, 1992

UDC 666’942 : 666 97 1’4 : 543 : 546’217

BUREAU OF INDIAN STANDARDS

MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
/NEW DELHI 110002

Gr 1 August 1988
 IS : 4031 ( Part 12 ) - 1988

Indian Standard
METHODS OF PHYSICAL TESTS FOR
HYDRAULIC CEMENT
PART I2 DETERMINATION OF AIR CONTENT OF
HYDRAULIC CEMENT MORTAR

( First Revision )
0. FOREWORD

0.1 This Indian Standard ( Part 12 1 ( First Revi- of individual tests. Further, since publication of
sion ) was adopted by the Bureau of Indian the original standard in 1968, a number of
Standards on 22 April 1988, after the draft final- standards covering the requirements of different
ized by the Cement and Concrete Sectional equipment used for testing of cement, a brief
Committee had been approved by the Civil description of which was also covered in the
Engineering Division Council. standard, had been published. In this revision,
therefore, reference is given to different instru-
0.2 Standard methods of testing cement are ment specifications deleting the description of the
essential adjunct to the cement specifications. instruments, as it has been recognized that repro-
This standard in different parts lays down the ducible and repeatable test results can be obtained
procedure for the tests to evaluate the physical only with standard testing equipment capable of
properties of different types of hydraulic cements. giving desired level of accuracy. This part
The procedure for conducting chemical tests of ( Part 12 ) covers determination of air content of
hydraulic cement is covered in IS : 4032-1985*. hydraulic cement mortar.
0.3 Originally all the tests to evaluate the 0.4 For the purpose of deciding whether a parti-
physical properties of hydraulic cements were cular requirement of this standard is complied
covered in one standard; but for facilitating the with, the final value, observed or calculated,
use of this standard and future revisions, it has expressing the result of a test or analysis, shall be
been decided to print the different tests as rounded off in accordance with IS : Z-1960*.
different parts of the standard and accordingly, The number of significant places retained in the
this revised standard has been brought out in rounded off value should be the same as that of
thirteen parts. This will also facilitate updating the specified value in this standard.
_____~
*Method of chemical analysis of hydraulic cement *Rules for rounding off numerical values ( revised ).
(first revision ).

1. SCOPE 3. TEMPERATURE AND HUMIDITY

1.1 This standard ( Part 12 > covers the procedure 3.1 The temperature of moulding room, dry
for determination of air content of hydraulic materials and water shall be maintained at
cement mortar for evaluating the properties of 27 f 2°C. The relative humidity of the laboratory
masonry cement or masonry mortars. shall be 6.5 i: 5 percent.
4. GENERAL
2. SAMPLING AND SELECTION OF TEST
SPECIMENS 4.1 Standard Sand - The standard sand to be
used in the test shall conform to IS : 650-1966*.
2.1 The samples of the cement shall be taken in
accordance with 5. APPARATUS
the requirements of IS :
3535- 1986* and the relevant standard . 5.1 Cylinder Measure - Cylinder measure
fication for the type of cement being testeds.‘%i and accessories conforming to IS : 11263-
representative sample of the cement selected as 1985t.
above shall be thoroughly mixed before testing.
*Specification for standard sand for testing of cement
(first revision ).
*Methods of sampling hydraulic cements (firsr $ Specification for cylinder measures for determi-
revision ). nation of air content of hydraulic cement mortar.

1
IS : 4031 (.Pa.rt 12 ) - 1988

5.2 Balance - The balance used in weighing mixer at slow speed ( 140 f 5 rev/min ). Immedi-
materials shall conform to the following require- ately determine the mass of 400 ml of mortar.
ments: Place the mortar gently in the 400 ml measure in
On balance in use, the permissible variation at three equal layers, spading each layer thoro-
a load of I 000 g shall be f 1’0 g. The permis- ughly with the spatula around the inner surface
sible variation on new balance shall be one-half of the measure. In spading the first layer, do not
of this value. The sensibility reciprocal shall be strike the spatula forcibly against the bottom of
not greater than twice the permissible variation. the measure. In spading the second and final
NOTE 1 - The sensibility reciprocal is generally de- layers, use only enough force to caust the spatula
fined as the change in load required to change the to penetrate the surface of the previous layer.
position of rest of the indicating element or the After the measure has been filled and spaded in
elements of a non-automatic indicating scale a definite the above manner, tap the sides of the measure
amount at any load. lightly with the flat side of the tapping stick once
NOTE 2 .- Self-indicating balance with equivalent
accuracy may also be used.
each at five different points at approximately
equal spacing around the’outside of the measure
5.3 Standard Weights - The permissible vari- in order to expel entrapped air. Take care that
ations on weights in use in weighing the cement no space is left between the mortar and the inner
shall be as prescribed in Table 1. surface of the measure as a result of the spading
TABLE 1 PERMISSIBLE VARIATION ON WEIGHTS
operation. Then cut the mortar off to a plane
surface, flush with the top of the measure, by
WEIQIVI PERYISWIBT~E VARIATION ON drawing the straight edge with a sawing motion
WE1fJETS IN USE PLUS OH
across the top of the measure, making two passes
hfrN1.s
over the entire surface, the second pass be ing
g g made at right angles to the first. Take care in
500 0.35 the striking off operation so that no loose sand
300 0.30
250 0.25 grains cause the straight edge to ride above the
200 0.20 top surface of the measure. Complete the entire
100 0’15 operation of filling and striking off the measure
0’10 within one and a half minute. Wipe off all mortar
:o” 0’05
10 034 and water adhering to the outside of the measure.
0.03 Weigh the measure and its contents ( see Note ).
z 0.02 Record the mass of the mortar in grams, after
1 0.01 subtracting the mass of the container.
NOTE- This operation may be facilitated by placing
5.4 Planetary Mixer _L
Planetary mixer con- the measure on a steady flat-surfaced support of lesser
framing to IS : 10890-1984*. diameter than the measure while filling and wiping.
5.5 Flow Table and Accessories-Flow table 6.3 Determination of Density of Cement -
and accessories conforming to IS : 55 12-19831. Determine the density cement in the usual
manner by the displacement of liquid in a Le
5.6 Tamping Rod - Tamping rod conforming
Chatelier flask as described in IS : 4031 ( Part
to 6.1 (c) of IS : 10086-1982J.
11 ) - 1988*.
6. PROCEDURE 7. CALCULATION
6.1 Preparation of Mortar-Prepare mortar 7.1 Calculate the air content of the mortar and
for the air entrainment test as given in 7 of report it to the nearest 0’1 percent, using the
IS : 403 1 ( Part 7 j-19885 except that the following formulae:
amount of water used for gauging shall be such as
to produce a flow of 80 to 95 percent with 10 A=lOO- -+, and
drops in six seconds.
6.2 Determination of Mass of 400 ml of M, +M,+v”
Mortar - When the quantity of mixing water to D=A!ll M
s;-+g+V”
produce a flow of 80 to 95 percent ( with 10 2
drops in 6 s ) has been found, return the mortar where
on the flow table to the bowl and remix for 15 s n= percentage of entrained air by
with the remainder of the mortar, using the volume,
Mm = mass of 400 ml of mortar in g,
*Specification for planetary mixer used in tests of D = density of air-free mortar,
cement and pozzolana. Ml = mass of cement in g,
tSpecific&ion for flow table for use in tests of hydra- M, = mass of standard sand in g,
ulic cements and pozzolanic materials (first
. revision ).
VW = volume of water used in cm3,
++Specificationfor moulds for use in tests of cement and
concrete & = density of cement, and
$ Methods for physical tests for hydraulic cement : & z density of standard sand.
Part 7 Determination of compressive strength of masonry *Methods of physical tests for hydraulic cement:
cement ( firsr revisiorz ) Part 11 Dexrmination of density (first revision ).
2

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