IS : 2185 ( Part 3} • 1984( Superseding IS : 5482-1969)

(Reaff i rmed 2010) ( Reaffirmed 2005)

Indian StandardSPECIFICATION FOR

CONCRETE MASONRY UNITS

PART 3 AUTOCLAVED CtZLLULAR (AERATED)CONCRETE BLOCKS

( First Revision )

First Reprint DECEMBER 1989

UDC 683.5:691.327.332-1437

® Copyright 1985

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 HAHADUR SHAH /AFAR MARC

NEW DELHI 110002

March 1985

IS . 2185 (Part 3) -ISM5MZ-1N9)

Indian^ StandardSPECIFICATION FOR

CONCRETE MASONRY UNITS

PART 9 AUTOCLAVED CELLULAR ( AERATED )CONCRETE BLOCKS

( First Revision )

Cement and Concrete Sectional Committee, BDC 2

RffHtsaitiiifDR H. C. Vw\nw»A*AY\t Research Institute of India, New" Delhi

ADDITION AL DIBXOTOX, STANDARD* Research, Design* & Standard* Organization( B 4. S ) ( Ministry of Railways ), Lttckoow

DKTUTY DIBKCTOH, STANDARDS

SHKI K. P. B.unERJXK Larsen & Toubro Ltd, BombaySHKI HARIBH N. MALAWI ( Alttrnait )

SHJII S. K. BAHKKJKK National Test Home, Calcutta,DB N. S. BHAL Structural Engineering Retcarch Centre (CSIR ),

RoorkeeSHKI V. K. GM AXXXAK ( AUemett >

SH»I S. P. CM AintABO»M Road* Wing, MiwMry 01 Shipping and Transport,New Delhi

SHRI N. SBITAOTJ»D ( Allmttt )CBIBT EXOIKKZB ( BD ) Beat Designs Organization. Nangal Township

Sni J. C. BA«U» (AlltrMU)CHIKV ENanrxxB ( DKHOVB } Central Public Works Department, New Delhi

E X X O U T I T B E K O I K K K B(DMI..MS) III (AlttnaU)

CHIEF Eycnrcn (RMXABCX)- Irrigation Department, Government of Punjab,Crm-DntBoro* Chandigarh

RBSIKABCX Ornca ( IPRI ) ( AIitm*tt )D» S. K. CBOPBA Cement Research Institute of India, New Delhi

DR A. K. Muuicx (AUtntH)(C*itiiuu<t»iipagi2)

O &0ritl* 1985BUREAU OF INDIAN STANDARDS

This publication is protected under the /IU&M Ctfyright Act (XIV of 1957) andreproduction ia whole or in part by smy means except with written permission of thepublisher shall be deemed to be an infringement of copyright under the said Act.

IS i 2185 (Part 3)-1M4

1}

Research Laboratories,Mtntbtri

DIBEOTOB A. P. EngineeringHyderabad

DmicTOK Central Soil & Materials Research Station,New Delhi

DKTOTT BIBBOTOB ( Alttrnatt)DIBEOTOB ( C & MDD-I) Central Water Commiauon, New Delhi

DBTUTTDIBICTOB (C& MDD-I) (Alitnatt)SHBI T. A. E. D'SA The Concrete Association of India, Bombay

SHBI N. C. D00GAL (Alttrnatt )SHBI A. V. GOKAK Cement Controller (Ministry of Industry k=x

SHBI S. S. MIOI.AIII ( Alttnatt) JVSHBI A. K. GUPTA Hyderabad Asbestos Cement Produ|fc»'' Ltd,

Hyderabad JOSHBI P. I. JAODS The Associated Cement Companies KwftBombay

SHBI M. R. VINAYAKA ( Alttnatt ) ^SHBI N. G. JOSHI ' Indian Hume Pipes Company LtdTBpmbaySHBI S. R. KOLKABNI M. N. Dastur & Co. Pvt Ltd, BombaySHBI S. K. LAHA The Institution of

SHBI B. T. UHWALLA ( Altematt)SHBI G. K. MAJUMDAB Hindustan Prefab Ltd,

SHBI H. S. PASBICHA ( AUeraatt) ^tkSHBI K. K. NAMBIAB T- P.~«AJ 'i

SHBI Y. R. PHDLI,SHBI Y. R. PHULL

D«»H

), Calcutta

DelhiInstitute

laya'Afar, Madnt)

(CSIR),

SHBI M. R. CHATTBHJJUS ( Alt*.SHBI K. L. SBTHI ( Alttnuti II) " f

DB MOJIAN RAI ^ Central Building Research Institute ( CSIR ),JO" Roo|ke '

DB S. S. REIISI ( AlttrnaH) ffm~ ^'^' Dalmia Cement ( Bharat ) Ltd, New DelhiSHBI A. V. RAMAN A

DB K. C. NARANO ( ADB M. RAMAIAM ":

^

— ,., ---- .,_^«^ .

,Structural Engineering Research Centre, ( CSIR ) ,

DBA. V.R.RAOSHBI J. SEN GUPTA ( Altmute )

SHRI R. V, CjoAXArATHi RAOSBBI S. ROT ( Alttmaii)

SHBI T. N. .S. RAO

SHBI ABJUS RUHSIMOHAMISHBI C. S. SHABMA (Alttnuie )

SHBI H. S. SATYAHABATAICA

SHBI V. R. Koran (Alttnatt )SXCBBTABT

SHBI K. R. SAXBHA ( AUtnutt )

torate General of Supplies and Disposals,New Delhi

National Buildings Organization, New Delhi

Geological Survey of India, Calcutta

Gammon India Ltd, Bombay

Cement Corporation of India Ltd, New Delhi

Engineer-in-Chief's Branch, Army Headquarters,New Delhi

Central Board of Irrigation and Power, New Delhi

15)

IS t 2185 (Part 3)-1984

Indian StandardSPECIFICATION FOR

CONCRETE MASONRY UNITS

PART 3 AUTOCLAVED CELLULAR (AERATED )CONCRETE BLOCKS

( First Revision)

0. F O R E W O R D

0.1 This Indian Standard (Part 3) (First Revision ) was adoptedIndian Standards Institution on 30 April 1984, after the draft finaUzgd bythe Cement and Concrete Sectional Committee had been approvetj by theCivil Engineering Division Council.

0.2 A series of National Standards on theformulated so as to provide standard proof buildings. Cellular concrete is a class 'developed commercially abroad and is coming inalso. This specification is intended for celjiilar ( aer;and its manufacture using the method of genera'"^action, the details of which are broaSectional Committee responsible- foihowever, no intention to freeze the'|particular method. """""'

as beenstructionhas been

in this countryconcrete blocks

gas by chemicalAppendix A. The

of this standard has,anufacture to any one

0.3 Concrete masonry, already extensively used in building constructionabroad, is likely to make^vefy considerable headway in this countrybecause of the many advantages, such as durability, strength andstructural stability, fire resistance, insulation, and sound absorption itpossesses. Concrete masonry construction is also economical because ofthe following aspects:

a) The units are relatively large^aad true in size and shape. Thisensures rapid construction so that more wall is laid per man-hourthan in other types of wall construction;

b) Fewer joints result in considerable saving in mortar as comparedto normal masonry construction, and also in increasing thestrength of the wall; and

IS t. 2185 (Part 3) -ISM

c) The true plane surfaces obtained obviate necessity of plaster forunimportant buildings situated in low rainfall areas; even whenplaster is used for any reason, the' quantity required forsatisfactory coverage is significantly small.

0.3.1 Concrete masonry has an attractive appearance and is readilyadaptable to any style of architecture. It lends itself to a wide variety ofsurface finishes for both exterior and interior walls. It may also befinished with cement plaster, gauged with lime or a plastkizer. Concretemasonry units provide a strong mechanical key, uniting the concretemasonry backing and the plaster finish in a strong permanent bond.

0.3.2 Autoclaved cellular (aerated) concrete blocks are .used foload bearing and. non-load bearing internal walls, partition an| panelwalls, inner leaf of cavity walls or as backing to brick masonry and forexternal load-bearing walls as well as panel walls in steel or|reinfbrcedconcrete frame construction when protected from weath«r4iyt renderingor by some other efficient treatment. /-§>

0.4 This standard was first publishedSpecification for autoclaved cellular conis being issued as IS : 2185 ( Part 3"Specification for concrete masonry(aerated) concrete blocks" and{fiU]IS: 5482-1969. Part 1 of this staTblocks of normal weight and Part 2 jpovers

18 : 5482-1969first revision

modified titletoclaved cellularformer standardand solid concrete

and solid light weighthi title intended for facilitating dierious types of concrete masonry units,

andante^*

concrete blocks. This modifico-ordination of requiremencovered under various Indi

0.4.1 This standard incorporatevsi|nificant modifications specially withregard to materials and physical requirements such as dimensions, surfacefinish and texture. Rsquirement of fire resistance has been omitted fromthis revision and thermal conductivity has been retained. A clause onterminology has been added in this revision.

0.5 For the purpose of deciding whether a particular requirement ofthis standard is complied with, the final value, observed or calculated,expressing the result of a test or analysis, shall be rounded off hiaccordance with IS : 2-1969*. The number of significant places retainedin the rounded off value should be the same as that of the specifiedvalue in this standard.

•Rules for rounding off numerical values (rttiud).

4

IS : 21*5 (Part 3) - 1»S4

1. SCOPE

1.1 This standard (Fart 3 ) covers the requirements of autoclaved cellular(aerated ) concrete blocks having density up to 1 000 kg, m*.

2. TERMINOLOGY

2jO For the purpose of this standard, the following definitions shallapply.

2.1 Autoclaved — Steam curing of concrete products, sandlitne bricks,asbestos cement products, hydrous calcium silicate insulation products,cement hi an autoclave at maximum ambient temperaturesbetween 170 and 215*C.

2.2 Block — A concrete masonry unit, any one of the external diof which is greater than the corresponding dimension ofspecified in IS: 3952*1978*', and of such size and mass as tobe handled by one man. Furthermore, to avoid confusionpanels, the height of the block shall not exce l either ittimes its width. . ' ,f^> ""

Block Density — The 'density calculated by dMtong the mass of ablock by the overall volume, including holes or caymgprand end recesses.

c*2.4 Drying Shrinkage — The difler^nc^ betwee||the length of specimenwhich has been immersed in wjUej? andjhejv'subsequentiy dried toconstant length, all under specified^ndition^^pcpressed as a percentageof the dry length of the specimen. , •

23 Gross Area —The total area occupied by a block on its beddingface, including areas of the i;avitiei and end recesses.

2£ Height — The verScal dimension of the exposed race of a block,excluding any tongue or other device designed to provide mechanicalkeying.

2.7 Length — The horizontal dimension of the exposed^ face of a block,excluding any tongue or other device designed to provide mechanicalkeying.

2JI Width —The external dimension of a block at the bedding plane,measured at right angles to the length and height of the block.

for (Mattel*? hollow blotto for wall* jpd pMtitMM»(>*>MwiM).

' 5

IS: 2185 (Part 3)-1984

3. DIMENSIONS AND TOLERANCES

3.1 Concrete masonry building units shall be made in sizes and shapes tofit different construction needs. They include stretcher, corner, doublecorner or pier, jamb, header, bull nose, and partition block, and concretefloor units.

3.2 Concrete Block — Concrete block shall be referred to by its nominaldimensions. The term 'nominal' means that the dimension includes thethickness of the mortar joint. Actual dimensions shall be 10 mm short ofthe nominal dimensions (or 6 mm short in special cases wherejointing is specified).

3.2.1 The nominal dimensions of the concrete block shall be as follows:

Length 400, 500 or 600 nun

Height 200, 250 or 300

Width 100, J50.200 or!

In addition, block shall be manufactured in h^l£|engths of 200, 250or 300 mm to correspond to the full len //x^*v

The nominal dimensions of the units are jrewsigned that takingaccount of the thickness of mortar Joints, they Jj) produce wall lengthsand heights which will conform to t^principlei|tf modular co-ordination.

3.2.2 Blocks of sizes other thwOhose specrafed in &2.1 may also be usedif so specified. In the case of special concrete masonry units such as jallieor scretn wall block and ornamental blocl, the specified sizes may notnecessarily apply.

3.2.3 The maximum^vjfcftation m the length of the units shall not bemore than ± 5 mm ahc| the maxiouim variation in the height and widthof unit, not more than* 3 mm (stt Fig 1 for mode of measurement ).

3.3 Subject to the tolerances specified in 3.2J and the provisions of 3.4the faces of masonry units shall be flat and rectangular, opposite facesshall be parallel, and all arises shall be square. T^be bedding surfacesshall be at right angles to the faces of the blocks.

3.4 Block* with Special Faces— Blocks with special faces shall bemanufactured and supplied if so specified.

4. CLASSIFICATION

4.1 The autoclaved cellular concrete blocks shall be datrifittfi in twogrades according to their compressive strengths as indicated in Table 1 .

IS i 2185 < Part 3)-1984

(a) Four Position* for Checking Length of WholeBlocks and for Measuring Length of CutSpecimens

(b) Six Positions for Checking Height of WholBlocks

FIG. 1 CHECKING AMD ONS OF BLOCKS

TABLE 1 PHYSICAL PK,OPER .UTOCLAVED CELLULAR

U, lI.Swu/11.4)

SL DKSHTY IN OTB^TDBYNo. CONDITION

U)

i)ii)

iii)iv)v)

(2)kg/m»

451 to 550551 to 650651 to 750751 to 850851 to 1 000

CoimusiVB STBKUOTH, TaiouMin VITI

fGrade 1

(5)N/mm«

2-04-05-06-07-0

Grade 2 •

(4)

N/mm1

1-53-04-05-06-0

•AX. CosDwcn-r m Am DBTJoirnrnon

(3)W/m.k

0-210-240-300-370-42

Bs2it5(Part3)-lM4

5. MATERIALS

5.1 Gemeat— Cement complying with any of the following IndianStandards may be used at the discretion of the manufacturer:

IS: 269-1976 Specification for ordinary and low heat Portlandcement (third nmsiam).

IS: 455-1976 Specification

IS: 1489-1976 Specification(Mcmdnrinm)

for Portland slag cement (third rmtioit)

for Portland poaaolana cement

a) Said — Conformwhich may beshall not be

IS: 6909-1973 Specification for supersulphated cement

IS: 8041-1978 Specification for rapid hardening Portland(fait rtvititn)

IS: 8042-1978 Specification for white Portland cementrrnnm) «~*

IS:8043-1978 Specification for hydrophbbic For(Jarst rnisun) ' o^k^

5.1.1 Use of fly ash conforming to IS: 3812-1981 *a limit of 20 percent in cement conforming to ISit shall be ensured that blending of fly ash withpossible, to achieve maximum uniformity.

54 Lime — The lime shall satisfy tHSpecified in IS: 712-1973$.

5.3 Aggregate — Theconcrete blocks shall

cement

permitted toHowever,

it as intimate as

for Class C lime

manufacture of cellularrequirements:

970§ except for the gradingproduct and the silica content

b) Ffy Adi — Conforming to 15:3812-1981* with loss on ignitionnot more than 6 percent.

c) GroHMiaUd Blatt Rmact Slag—Generally conforming to Notes 1and 2 of 44 of IS: 455-1976J may be used.

•Specification for fly aia for use M pozzolana and admixture (Jtnt fwtriex).tSpecttcadoa for ordinary and low heat Portland cement (Mud muint).ISpedScation for builda| UDM ( mmdimuim).jSpacification for coan* and fin* aggng*t8* from natural toorcei for concrete

•Specification for Portland slag cement (Hard TOMM ).

8

IS » 2115 (Part 3j-lttt

5.4 Water — The water toed in die manufacture of concrete masonryunits shall be free from matter hannfol to concrete or reinforcement, ormatter likely to came efflorescence in the units and shall meet therequirements of IS: 456-1978*.

£5 Additive* or Admixture* — Additive* or admixtures may beadded either as additives to .the cement during manufacture, or asadmixtures to the concrete mix. Additives or admixture* used in the»««f«Mffrfftqif^ of concrete masonry Mt*it> may bet

a) accelerating, water-reducing and air-entraining admixturesconforming to IS:9103-197dt>

b) waterproofing agents conforming to IS: 2645-1975J, andc) colouring pigments.

>*.

Where no Indian Standards apply, the additives or admix;shall be shown by test or experience, to be not detrimentaldurability of the concrete.

«. MANUFACTURE

C.1 The aerated structure or the cells of the cellibe formed by generation of a gas by chemical *jttj|cn, withftBl^mix, priorto hardening with the aid of suitable cheimcal foa|iipg agents andmixing devices. The cells in the block shall be ij ributed evenlythroughout its volume. Broad principles for the .paanufacture of theautoclaved cellular concrete blocks are given in Appendix A for guidance

• ' Z™< -~~^ •*«• w ••

y* ,7. SURFACE TEXTURE AND FINISH

7.1 Concrete -masonry units cajrtt;be given a variety of surface texturesranging from a very'fine close textttre (to a coarse open texture by theproper selection, grading, and proportioning of aggregates at the time ofmanufacture. Textures may also be developed by treating the face of theunite while still green by wire brushing or combing, by slightly erodingthe surface by playing a fine spray of water upon it, and by splitting(split block ). Colour may be introduced by incorporating non-fadingmineral pigments in the facing concrete, or by applying a colouredcement grout or paint to the face of the units soon after they are removedfrom the moulds. Selected coloured aggregates may also be used .in thefacing and exposed by washing with water or dilute hydrochloric acid.

•Code of practice for plain and reinforced concrete ( Wtdnritim).tSpecification for admixture* for concrete.{Specification for integral cement water proofing compound* (fnt naitit*).

1* 1.2185 (Fart 3)-li«4

7.2 Well made concrete masonary, may not require piaster in case ofunimportant buildings in low rainfall areas; two or three coats of a cement

'paint being sufficient to render it resistant to rain water. If, however,it isintended to plaster concrete masonry, the block shall have a sufficientlyrough surface to afford a good key to the plaster. Waterproofingadmixtures may he used for .preparing the plaster.

8. PHYSICAL REQUIREMENT*

8.1 General — All units shall be sound and free of cracks or other defectswhich interfere with the proper placing of unit or impair the strength orperformance of the construction. Minor chipping resulting £ror~ *v~customary methods of handling during delivery, shall not begrounds for rejection.

8.1.1 Where units are to be used in exposed wall cohstruction^Jhe faceor faces that are to be exposed shall be free of chips, cra|fcs, or otherimperfections, except that if not more than 5 percent of Consignmentcontains slight cracks or small chipping* not larger tfcan-^S^Km, this shallnot be deemed grounds for rejection. *

iL2 Dimension* — The overall dimensio^ of the^aaSak when measuredas given in 3.2.3 shall be in accordance wip 3.2.1 |$|t to the tolerancesmentioned in 3.2.3. //;%,

8.3 Block Density — The block density shiconfonn to the require-ments specified in Table 1 when tested in accordance with 9.1.. . .8.4 Cosnprcasive Strength —The minimum compressive strength,being the average of twelve units, thall be as prescribed in Table Iwhen tested in accordance.with 9^L^^

8.5 Thermal Condutj&vlty —The thermal conductivity shall notexceed the values specified in Table 1 when tested in accordance

"

&& Drying Shrinkage — The drying shrinkage shall be not more than0'Q5 percent for Grade 1 blocks and 0* 10 percent for Grade 2 blocks whentested in accordance with 9.4.

9. TESTS

9.1 Block Density — The block density shall be determined in themanner described in IS : 644 1 ( Pan 1 )- 1972*.

'Methods of te*t for autoclared cellular concrete product* : Part 1 Determination ofunit weight or bulk density and moisture content.

10

IS t 2115 (Part 3 ) - 19*4

9.2 Compressive Strength— The compressrve strength shall bedetermined in accordance with IS: 6441 ( Part 5 )-1972».

9J Tkenaal Qtrndvctivity — The thermal conductivity shall bedetermined in accordance with IS: 3346-1980T.

9.4 Dryiag Shrinkage - The drying shrinkage shall be determined inthe manner described in IS : 6441 (Part 2 )-1972J.

10. SAMPLING

10.1 Lot — In any consignment, all the blocks of the same size and frothe same batch of manufacture shall be grouped together into a minimunumber of groups of 10 000 blocks or less. Each such group shsconstitute a lot. •

10.2 From each lot a sample of 24 blocks shall be selectedIn order to ensure randomness of selection, all the blocks in the|fet maybe arranged in a serial order. Starting from any^rjindom blocj^ex/ery rthblock may be selected till the requisite number ij ^ainedgij Tjemg theintegral part of JV/24-, where Jf is the lot size. "

10.3 The required number of blocks shall beoeken atjfr|fular intervalsduring the loading of the vehicle or the vintoskding ofjrajfc*vehicle depend-ing on whether sample is'to be taken Be%fe dejiyefcy or after delivery.When this is not practicable, the sample shall be talQn from the stack inwhich case the required . number o£ blocks shall' be taken at randomfrom across the top of the stacks, the sides accessible and from theinterior of the stacks by opening trenches fromjiche top.

10.4 The sample of blocks shall be marked for future identification of theconsignment it represents. $JJ3JP blocks;; shall lrt kept under cover andprotected from extreme conomons of te:iiiperature, relative humidity andwind until they are required for test. The tests shall be undertaken assoon as practicable after the sample has been taken.

10.5 Number of Tests

10.5.1 All the 24 blocks shall be checked for dimensions and inspectedfor visual defects.

•Methods of tot for a'utoclavcd cellular concrete products: Part 5 Determination ofr.ompreuiw itrength.

tMethods for the determination of thrrmal conductivity of thermal insulationmaterials (two stab, gutrJrd hot-olate method ) (tint rtvtsint ).

)M«tbo<b of test for autociaved cellular concrete products : Part 2 Determinationof drying shrinkage.

11

IS:21S5(P*rt3)-lM4

1«A2 Out of the 24 blocks, 12 blocks shall be subjected to the test forcompresuve strength, 3 blocks to the test for density, 3 blocks to the test forthermal conductivity, and 3 blocks to the test for drying shrinkage. Theremaining 3 blocks shall be reserved for re-test for drying shrinkage if aneed arises.

11. CRITERIA FOR CONFORMITY

11.1 The number of blocks with dimensions outside the tolerance limitand or with visual defects, among those inspected, shall not be more thantwo*

1L2 For density, the mean value shall be within the range specified inTable 1. '

11.3 For compressive strength, the mean value, say A' *Jl|lT' be deter-mined. The test results shall be grouped into groups «Jf*:and individualvalues of ranges shall be determined and the aveiagejfiiige R calculatedfrom these values and shall satisfy the following

X - 0-6 R > minimum value ipecified in Table 1.

11.4 For thermal conductivity, the mean value Shall be equal to or lessthan the value specified in Tat"

11.5 For drying shrinkage,£all the test specimens shall satisfy therequirements of the test. JffOne or ®H% specimens fail to satisfy therequirements, the remaining 3 blocks shall be subjected to these teats. Allthese blocks shall satUfy^prequireflieiits.

12. MANUFACTURER'S CERTIFICATE

12.1 The manufacturer shall|satisfy himself that the masonry unitsconform to the requirements of this specification and, if requested, shallsupply a certificate to this effect to the purchaser or his representative.

13. INDEPENDENT TESTS

13.1 If the purchaser or his representative requires independent tests, thesamples shall be taken before or immediately after delivery, at the optionof the purchaser or his representative and the tests shall be carried out inaccordance with this specification.

13.2 The manufacturer shall supply free of charge the units required fortesting.

12

IS t 2185 (Fart 3)-1984

14. STORAGE

14.1 General requirements of storage of autoclaved cellular (aerated)concrete blocks •hall be as described in IS: 4082-1977*.

15. MARKING

15.1 Each lot of concrete masonry units manufactured in accordancewith thai specification shall be suitably marked with the followinginformation:

a) The Identification of the manufacture;

b) The grade and block density of the unit; and

c) The month and year of manufacture. .,c

15.1.1 Each block may also be marked with the ISI CertificationMark.

NOM — The use of the ISI Certification Mark is governed by the(he Indian Standards Institution (Certification Marks) Act andRegulations made thereunder. The ISI Mark on .Standard coureys the assurance that they have beenrequirements of that standard under a well-definedquality control which is devised and superri*ed by ISISI marked products are also- continuously check "standard as a further safeguard. Details of conditiuse of the ISI Certification Mark may be ,may be obtained from the Indian Standards'

of,et andIndian

with the:esting andproducer,

ty to thatlicence for the

processors)

xx ,-•- • —MANUFACTURE OF AUTOCLAVED CELLULAR

CONCRETE BLOCKS

A-l. Cellular concrete blocks involve the use of aerated concrete whichis made by introducing air or other gas into a slurry composed of cement( f u 5.1) or lime ( ue 5.2) and a siliceous filler (set 5.3) so that when themixture sets hard after autoclaving, a uniform cellular structure isobtained. There are several ways in which air-cells or other voids may

'Recommendations on stacking and storage of construction material! at site

13

IS > 2185 (Part 3 ) - 19M

be formed in the slurry as to result in a cellular structurea fter autoclaving,the principal ones of which are the following:

a) By the formation of gas by chemical reaction within the massduring the liquid or plastic stage, in the same way as carbondioxide is formed and used in aerating bread and baked;products; and •

b) By introducing air from without, either by adding to the slurryin the mixer a preformed stable foam such as is used in fife-fighting or by incorporating air by whipping (with the aid ofan air-entraining agent), in the manner in which egg-white maybe whipped to a light cream or foam.

A-2. Suitable steam-curing is practically unavoidable in makingconcrete blocks with cement as binder and the same is absolutelywhen lime is used. Generally, auto claving is done for aj18 hours at about 700 kPa and about 185°C, the heatingof pressure or cooling and lowering of pressure beingover a period of few hours.

A-3. Although simple in principle, the<|Wmmeautoclaved cellular concrete blocks is qiiit^ elasand or other siliceous material is generally grorequired degree of fineness which is usually comof ordinary Portland cement.

production ofiractice. The

to theirwith the fineness

14

!S:2185(Part3)-lM4

( Ctntinued from pagt 2 )

Memtert RepresentingSHRI K. A. SUBRAXABIAM The India Cement Ltd, Madras

SHBI P. S. RAMACKAXIIRAN ( Alternate )S tt J B B I M T B H D ixc l-'xtiixi'Rit Public Works Department, Government of

. ( DKSIQN« ) Tamil Nadu, MadrasEJCKCUTIV* EKOJMKKII ( SM & R. DIVISION ) ( Alternate )

SHRI L. SWAROOP . Orissa Cement Ltd, Now DelhiSHRI D. S. BIIAMDARI ( Alternate )

Sinn G. RAMAN, Director Grnpr.il. ISI .' JZx-tffidf Mmber)Director ( Civ Engg )

SecretarySHUI N. G. I!A>-I>YI)PADHYAV

Deputy Dirrctor ( Civ Engg ), ISI

Precast Concrete Products Subcommittee, BDC 2 : 9

Hindustan Prefab

CanoenerS)iiu G. K. MAJCMDAK

MembertDJCPUTY DIREITOB, STANI>ARI>S Research, Di

( B & S ) MinistryA S S I S T A N T Di KKUTOU ,

STANDARDS ( U & S )-II( Alternate)

SHUI C. G. VITHAI, RAO (Alternate) ,'f-^,. !

CeDIRECTOR

DKPDTY DIRKCTOR ( Alternate )SHRI Z. GEOROE ^befictura^

x;

DR A. G. MADHAVA RAO ( .l|iSHRI V. G. GOKHAI.B o^ 'SUBI B. K. JIHDAL

Organization,IW

aterials Research Station,

ginoering Research Centre

DB S. S. Rxiisi ( AlternateSHBI L. C. LAISHRI S. NARAROY

ateY

tt )Hombay <3iiemicali Fvt Ltd, BombayCentraOnilding Research Institute ( CSIR ),

^ '*In personal capacity ( B;17, Wett End, JVew Delia )Engineering Construction Corporation Ltd,

MadrasSnu: A. RAKAXBISIIHA ( Alternate )

SIVRI D. B. NAIK Engineer-in-Chief's Branch Army Headquarters,New Delhi

SHRI SCCHA SINQH ( AUirnati )SHRI K. K. NAMBIAR In personal capacity ( 'Ramanaljt' 11 First Crescent

Park R«ut, GmaTuaagar, Afya, Madras )SHRI B. V. B. FAI The Concrete Association of India, Bombay

SBRI P. SBIKITASAN ( Alternate )

mp*gi 16)

15

IS i 21*5 ( Part 3) - 1M4

( Cntmtud frtm p*gt 15)

MtmkriSHBI H. S. PAMHJHA Hindustan Prefab Ltd, New DelhiDm N. RAGMATKKDB A Cement Rewarch Institute of India, New DelhiSBKI V. RAUAUXOAM Neyveli Lignite Corporation Ltd, Neyveli

Sum K. A. RAMABMAUBAM ( AUtnuti)DB A. V. R. RAO National Buildings Organisation, New Delhi

SHBI J. Sv:x GUPTA (Alttntttt)SMBI B. G. SJUUKK B. G. Shirke & Co Ltd, Pune

SBBI R. T. PAWAK ( Alitnute)SBBI C. N. SxmivABAJf M/s C. R. Narayana Rao, Madras

SMBI C. N. RAOBAVBICDWAK (Altnnatt)SurBmiMTKNi>u«o EsoiKBKB ( P & S ) Tamil Nadu Housing Uoard, Madras

Pnonecr OmcKB (Alurmtt)STTBTBTOR or . Central Public Works Department, New 1

WomJts(NZ)SUBTZTOB OF WORKS (NZ) (AlttrtuUi)

16

B U R E A U O F I N D I A N S T A N D A R D S

Headquarters.

Manak Bhavan, 9 Bahadur Shah Zafar Marg. NEW DELHI 110002Telephones: 331 01 31. 331 1375 Telegrams: Manaksanstha

( Common to all Offices)Regional Offices: TelephoneCentral Manak Bhavan, 9 Bahadur Shah Zafar Marg, (331 01 31

NEW DELHI 110002 (331 1375'Eastern : 1 /14 C. I. T. Scheme VII M, V. I P. Road. 36 24 99

Maniktola, CALCUTTA 700054Northern : SCO 445-446, Sector 35-C,

CHANDIGARH 160036

Southern : C. I. T. Campus, MADRAS 600113

{Western

2 1 8 4 33 1641

*41 24 4241 25 1941 2916

Manakalaya, E9 MIDC, Marol, Andheri ( East j, 6 32 92 95BOMBAY 400093

Branch Offices:'Pushpak', Nurmohamed Shaikh Marg, Khanpur,

AHMADABAD 380001JPeenya Industrial Area 1st Stage, Bangalore Tumkur Road

BANGALORE 560058Gangotri Complex, 5th Floor. Bhadbhada Road, T. T. Nagar.

BHOPAL 462003Plot No. 82/83. Lewis Road. BHUBANESHWAR 75100253/5. Ward No 29, R.G. Barua Road, 5th Byelane,

GUWAHATI 7810035-8-56C L. N. Gupta Marg ( Nampally Station Road ),

HYDERABAD 500001

263482 6 3 4 9

(384955138 49 56

6 67 16

53627 ,3 31 7-l4r

R1 4 Yudhister Marg. C Scheme, JAIPUR 302005

117/418 B Sarvodaya Nagar, KANPUR 208005

Patliputra Industrial Estate, PATNA 800013T.C. No. 14/1421. University P.O.. Palayam

TRIVANDRUM 695035Inspection Offices ( With Sale Point):Pushpanjali- First Floor. 205-A West

Shankar Nagar Square, NAGPURInstitution of Engineers (India ) Built

PUNE411005 J&v>, vv,/

9832#8768292

62305f6 21 04\ 21 17

251 71

aji Nagar, 5 24 35

oach, P. O. Princep 27 68 00

Chamber!. Grant Road, 896628

•Sale* Office in Calcutta i* at 5 Chowringhee AcStreet. Calcutta 700072 f ^

tSales Office in Bombay it at NoveltyBombay 400007

{Sales Office in Bangalore is at Unity Building. Narasimharaja Square, 22 3$ 71Bangalore 560002 ,

Reprography Unit, BIS, New Delhi, InJia