Is 4031_part12 2vpc

IS : 4031 ( Part 12 ) - 1988 ( Reaffirmed 1995 )

Indian Standard

METHODSOFPHYSICALTESTSFOR HYDRAULICCEMENT PART

12 DETERMINATION OF AIR CONTENT HYDRAULIC CEMENT MORTAR

OF

( First Revision ) First Reprint MARCH, 1992

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

BUREAU MANAK

Gr 1

OF BHAVAN,

INDIAN

STANDARDS

9 BAHADUR SHAH /NEW DELHI 110002

ZAFAR

MARG

August 1988

IS : 4031 ( Part

12 ) - 1988

Indian Standard METHODS OF PHYSICAL TESTS FOR HYDRAULIC CEMENT PART

I2

DETERMINATION OF AIR CONTENT HYDRAULIC CEMENT MORTAR

OF

( First Revision ) 0.

FOREWORD of individual tests. Further, since publication of the original standard in 1968, a number of standards covering the requirements of different equipment used for testing of cement, a brief description of which was also covered in the standard, had been published. In this revision, therefore, reference is given to different instrument specifications deleting the description of the instruments, as it has been recognized that reproducible and repeatable test results can be obtained only with standard testing equipment capable of giving desired level of accuracy. This part ( Part 12 ) covers determination of air content of hydraulic cement mortar.

0.1 This Indian Standard ( Part 12 1 ( First Revision ) was adopted by the Bureau of Indian Standards on 22 April 1988, after the draft finalized by the Cement and Concrete Sectional Committee had been approved by the Civil Engineering Division Council. 0.2 Standard methods of testing cement are essential adjunct to the cement specifications. This standard in different parts lays down the procedure for the tests to evaluate the physical properties of different types of hydraulic cements. The procedure for conducting chemical tests of hydraulic cement is covered in IS : 4032-1985*. all the tests to evaluate the 0.3 Originally physical properties of hydraulic cements were covered in one standard; but for facilitating the use of this standard and future revisions, it has been decided to print the different tests as different parts of the standard and accordingly, this revised standard has been brought out in thirteen parts. This will also facilitate updating _____~ *Method of chemical analysis of hydraulic cement (first revision ).

0.4 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS : Z-1960*. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

1. SCOPE

3. TEMPERATURE

1.1 This standard ( Part 12 > covers the procedure for determination of air content of hydraulic cement mortar for evaluating the properties of masonry cement or masonry mortars.

3.1 The temperature of moulding room, dry materials and water shall be maintained at 27 f 2°C. The relative humidity of the laboratory shall be 6.5 i: 5 percent.

2. SAMPLING SPECIMENS

4. GENERAL 4.1 Standard Sand - The standard sand to be used in the test shall conform to IS : 650-1966*.

AND SELECTION

OF

*Rules for rounding off numerical values ( revised ).

TEST

2.1 The samples of the cement shall be taken in accordance with the requirements of IS : 3535- 1986* and the relevant standard . fication for the type of cement being testeds.‘%i representative sample of the cement selected as above shall be thoroughly mixed before testing. *Methods revision

).

of

sampling

hydraulic

5. APPARATUS 5.1 Cylinder Measure - Cylinder and accessories conforming to IS 1985t.

:

measure 11263-

*Specification for standard sand for testing of cement (first

cements

AND HUMIDITY

(firsr

revision

).

$ Specification for cylinder measures for determination of air content of hydraulic cement mortar. 1

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

mixer at slow speed ( 140 f 5 rev/min ). Immediately determine the mass of 400 ml of mortar. Place the mortar gently in the 400 ml measure in three equal layers, spading each layer thoroughly with the spatula around the inner surface of the measure. In spading the first layer, do not strike the spatula forcibly against the bottom of the measure. In spading the second and final layers, use only enough force to caust the spatula to penetrate the surface of the previous layer. After the measure has been filled and spaded in the above manner, tap the sides of the measure lightly with the flat side of the tapping stick once each at five different points at approximately equal spacing around the’outside of the measure in order to expel entrapped air. Take care that no space is left between the mortar and the inner surface of the measure as a result of the spading operation. Then cut the mortar off to a plane surface, flush with the top of the measure, by drawing the straight edge with a sawing motion across the top of the measure, making two es over the entire surface, the second be ing made at right angles to the first. Take care in the striking off operation so that no loose sand grains cause the straight edge to ride above the top surface of the measure. Complete the entire operation of filling and striking off the measure within one and a half minute. Wipe off all mortar and water adhering to the outside of the measure. Weigh the measure and its contents ( see Note ). Record the mass of the mortar in grams, after subtracting the mass of the container.

5.2

Balance - The balance used in weighing materials shall conform to the following requirements: On balance in use, the permissible variation at a load of I 000 g shall be f 1’0 g. The permissible variation on new balance shall be one-half of this value. The sensibility reciprocal shall be not greater than twice the permissible variation. reciprocal is generally deNOTE 1 - The sensibility fined as the change in load required to change the position of rest of the indicating element or the elements of a non-automatic indicating scale a definite amount at any load. NOTE 2 .- Self-indicating balance with equivalent accuracy may also be used.

5.3 Standard Weights - The permissible variations on weights in use in weighing the cement shall be as prescribed in Table 1. TABLE 1 PERMISSIBLE WEIQIVI

VARIATION

ON WEIGHTS

PERYISWIBT~E WE1fJETS

VARIATION

IN USE

PLUS

ON OH

hfrN1.s g 500

g

0.35 0.30 0.25 0.20 0’15 0’10 0’05 034 0.03 0.02 0.01

300 250 200 100 :o” 10 z 1 5.4

Planetary

Mixer

This operation may be facilitated by placing NOTEthe measure on a steady flat-surfaced of lesser diameter than the measure while filling and wiping.

_L

Planetary mixer conframing to IS : 10890-1984*. 5.5 Flow Table and Accessories-Flow table and accessories conforming to IS : 55 12-19831. 5.6 Tamping Rod - Tamping rod conforming to 6.1 (c) of IS : 10086-1982J.

6.3 Determination of Density of Cement Determine the density cement in the usual manner by the displacement of liquid in a Le Chatelier flask as described in IS : 4031 ( Part 11 ) - 1988*. 7. CALCULATION 7.1 Calculate the air content of the mortar and report it to the nearest 0’1 percent, using the following formulae:

6. PROCEDURE 6.1

Preparation of Mortar-Prepare mortar for the air entrainment test as given in 7 of IS : 403 1 ( Part 7 j-19885 except that the amount of water used for gauging shall be such as to produce a flow of 80 to 95 percent with 10 drops in six seconds. 6.2 Determination of Mass of 400 ml of Mortar - When the quantity of mixing water to produce a flow of 80 to 95 percent ( with 10 drops in 6 s ) has been found, return the mortar on the flow table to the bowl and remix for 15 s with the remainder of the mortar, using the

A=lOO-

M, +M,+v”

D=A!ll M s;-+g+V” 2

where n

= percentage of entrained air by volume, Mm = mass of 400 ml of mortar in g, D = density of air-free mortar, = mass of cement in g, Ml M, = mass of standard sand in g, VW = volume of water used in cm3, & = density of cement, and & z density of standard sand. *Methods of physical tests for hydraulic cement:

*Specification for planetary mixer used in tests of cement and pozzolana. tSpecific&ion for flow table for use in tests of hydraulic cements and pozzolanic materials (first revision ). .

++Specificationfor moulds for use in tests of cement and concrete $ Methods for physical tests for hydraulic cement :

Part 7 Determination of compressive cement ( firsr revisiorz )

strength

and

-+,

of masonry

Part 11 Dexrmination

of density (first revision ).

2 Printed at Dee Kay Printers. New Delhi, India