2571-COP for laying insitu CC flooring

8/7/2019 2571-COP for laying insitu CC flooring

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is : 2571 - 1970(Reaffirmed 1996)

Indian StandardCODE OF PRACTICE FOR LAYING

IN-SITU CEMENT CONCRETE FLOORING( First Revision )

Sixth Reprint FE BRUARY 1999

UDC 69.025.331.3 : 69.001.3

0 Copyright 1971BURE AU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NE W DELH I 110002

Gr 7 November 1971


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Is ; 2571.1970Indian Standard

CODE OF PRACTICE FOR LAYINGIN-SITU CEMENT CONCRETE FLOORING( First Revision)

Flooring and Plastering Sectional Committee, BDC 5Chairman Refkesenting

SH RI 0. P. &TAL DireFe;;r General of Posts & Telegraphs, NewMembers

Da D. BANERJEE National Rubber Manufacturers Ltd, CalcuttaDa M. L. BHAWK ( Ahrmte ),$HRI A. K. BHATTACHARYYA National Test House, CalcuttaJ.,ALA G. C. DAS ( Affernn te

SHRXS. K. BOSE En gineer-in-Chiefs Bran ch, Arm y Headqua rt ersMAJ D. D. SHARMA ( Alternate )SHRI DINESHA. CHOK~HI Arcoy Industries, AhmedabadSHRI RA;;~~L A. CHOKSHI ( Alternatf )DEPUTY MECHANICAL Mmlstr y of Railways

ENGINEER, INTEGRAL COACHFACTORY,PERAMBURDEY~TY DIRE CTOR ( ARCH ),RESEARCH,DESIGNS NDSTAN-DARDS ORGANIZATION,LUCKNOW ( Alternate )

DIRECTOR Maharasht ra Engineering Research Institute, NasikR~SEARCE~ OFFICER, MATERIAL

TESTING DIVISION Alternate )SHRI P. K. DOCTOR The Concrete Associat ion of India , BombaySHRI N. HARXLALDa PRANLALPATEL ( Alternate) Oxy-Chloride Floorin g Pr oducts Ltd, BombaySHRI S. C. KAPOOR

SHRI A. C. KA~OOR (Alter na te)Modern Tiles & Mar bIe, N ew Delhi

SIXRIM. R. MALYA Bur ma h-Shell Oil Stora ge & Distr ibutin g Co of Ind iaDR B. S. B~ssr ( Ahnate ) Ltd, BombaySHRI HAZARI LAL MARWAH Cent ra l Builders Associat ion, New DelhiSHRI T. R. MEH ANDRU The Institu tion of En gineers ( India), Calcutt a

DR MOHANRAISHRI R. K. JAIN ( Ahmate) Centr al Building Resear ch Inst itute ( CSIR), Roork ee

SHRI M. V. MURUGAPPANSHRI R. SRINI VASAN Abemale ) Coroman del Pr odorite Pvt Ltd, Madras( Continued an page 2 )

BUREAU OF INDIAN STANDARDSMANAK BH AVAN, 9 BAHADUR SHAH ZAFAR MARG

NE W DELH I 110002


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ISr2571-1970( ontinuedfrom page 1 )

Members RePresentingSHRI H. M. NANDKE OLYAR India Linoleums Ltd, 24 Par ganas ( West Bengal )SHRI RAMAN M. PATEL The Bhor Industries Ltd, BombaySHRI J . M. SHROFF Alternate )DR A. V. R. RAO Nat iona l Buildings Organization, New DelhiSHRI 0. P. RATRA ( Alternate )SHRI G. S. SAVKAR Directorat e Gener al of Sup plies & DisposalsSHRI L. G. SELVAM Bur eau of Public En terpr ises ( Ministry of Fina nce )SHRI T. M. VARUGH ESE Alternate )SHRI G. C. SHARMA Indian Institu te of Architects, Bomba ySUPERINTENDINGNGINEERPLAN- Pu blic Works Depart ment , Governm ent ofNINOAND DESIGN CIRCLE Tamil NaduDEPUTYCHIEF ENGINEER BUILD-

INC? ( Altematc )SU;PE~~JIN~ SuR~i3v0R OF Cent ra l Public Works Depar tm ent, New DelhiSURVEYOROF WORKS I TO SSWI ( Alternate )SHRI D. AJ ITHA SIMHA, Director Gener al, IS1 ( Ex-ojicio Member )Director ( Civ En gg )

SecretarySHRI L. RAMACHANDRA AO

Depu ty Director (Civ En gg ), IS1


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IS:2571 1970Indian Standard

CODE OF PRACTICE FOR LAYINGIN-SITU CEMENT CONCRETE FLOORING( First Revision)0. FOREWORD

0.1 This Indian Standard ( First Revision) was adopted by the IndianStandards Instit.ution on 19 December 1970, after the draft finalizedby the Flooring and Plasterin? Sectional Committee had been approvedby the Civil Engineering Division Council.0.2 In-situ cement cencrete flooring consists essentially of rich cement con-crete, and pnssesses good wearing properties and facility of easy cleaningand maintenance which make it suitable for use in houses, offices, schools,hospitals and light industrial buildings. Depending upon the amount ofloadmg and the degree of wear sesistance needed, the floor finish has to belaid in various thicknesses and a careful selection has to be made regardingmix proportions, panel srzes and number of layers. Also the layingoperations have to ensure the proper bonding of the finish to the base orsub-floor. This code provides necessary guidance in the selection ofmaterials and laying and finishing of cement concrete flooring for obtainingsatisfactory performance. This standard which was first published in 1963is now being revised taking into account the experience gained in theconcrete flooring work for the past few years.0.3 In the formulation of this standard due weightage has been given tointernational co-ordination among the standards and practices prevailingin different countries in addition to relating it to the practices in the fieldin this country. This has been met by deriving assistance from B. S.CP204 : 1965 ZU-situ floor finishes, issued by the British StandardsInstitution.0.4 For the purpose of deciding whether a particular requirement of thisstandard is complied with, the final value, observed or calculated, ex_pressing the result of a test or analysis, shall be rounded off in accordancewith IS : 2-1960*. The number of significant places retained in therounded off value should be the same as that of the specified valie inthis standard.____.._._ .-

*Rules for rounding off numerical values (revised).3


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lsr2!57l-1970l.sGoPE1.1 This standard covers laying and finishing of in-h cement concreteflooring for non-industrial and light industrial buildings. Heavy dutyfloors and acid and ~alkali resisting floor finishes are not dealt with inthis standard.2. TERMbiOLOGY2.0 For the purpose of this standard, the following definitions shall apply.2.1 General T&s

2.1.i Base Cmcre& -.The layer of concrete on which the cement concretetopping is laid.2.1.2 Luitance - A thin layer, consisting essentially of fine cement parti-cles, which often forms a scum on the surface of freshly laid concrete.This layer may be formed by excessive surface trowelling of concreteimmediately after it has-been laid.2.13 Sub-baw- The prepared surface on ground on which base con-crete is laid.2.1.4 Sab-&ors - The prepared surface of structural/suspended floor onwhich the floor finish is laid.

2.2 Toolm ind Acceasoric?a22.1 &reed Ships - Temporary narrow strips of wood or steel laid on thesub-base or base concrete or sub-floor to act as guides-for dividing the areato he paved into panels.23.2 Scmd& Board- A straight-edged wooden scantling used forfloating a plane surface. It is moved with a sawing action, the two ends

( if necessary ) resting on screed strips or guides set at the correct height.23 site oper+onm

23.1 Scrteding -Bringing the floor to a true and even surface by meansof screeding hoard.3. NECESSARY INFORMATION3.1, For the efficiZnt planning and execution of the tiork , detailed informa-tion with regard to the following is necessary:

a) Purpose for which the floor is to be used;b) Floor area to be covered;


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44e>f-1EC)h)

IS : 2571-1970Location and size of openings and ducts, drainage outlets, if any,to be left out;Details of the sub-base or sub-floor;Type of soil in the sub-base and any seepageproblem;Specific requirements, if any, regarding the colour and appearanceof the finished surface and of aggregates to he llsed;Whether skirtings are required; andSlope to be provided in the floor finish.

3.2 All the information stated in 3.1 shall be made available by the appro-priate authority responsible for the construction of the whole buildingto those who are entrusted with the work of laying cement concrete floorfinish before the work is started. Necessary drawings and instructions forpreparatory work shall also be given where required.3.3 Arrangements shall also be made for the proper exchange of infor-mation between those engaged in laying the floor finish and all otherswhose work will affect or will be affected.4. MATERIALS4.1 Cement - Cement used for the floor finish work shall conform toIS: 269-1967* or to IS : 455-1967t or IS : 1489-1967$.4.2 Aggregates

4.2.1 Aggregates for cement concrete flooring mix shall conform to therequirements of IS : 383-19635. The aggregate crushing value, whendetermined in accordance with IS : 2386 ( Part IV)-196311 shall not exceed30 percent.4.2.1.1 Coarse aggregate - The grading of graded coarse aggregate forcement concrete flooring mix shall be within the limits given in Table 1.The coarse aggregate shall generally be of the following sizes:

a) Base concrete ( lean cement Graded from 40 mm and belowconcretf! or lime concrete )b) Cement concrete topping of Graded from 16 mm and belowthickness 40 mm and abovec) Cement concrete topping ofthickness 25 mm Graded from 12.5 mm and below

*Specification for ordinary, rapid-hardening and low heat portland cement (w&d).tSpecificajibn for portland blast-furnace slag cement (second r&ion ).$Specification for portland pozzolana citicnt ( revised .&Specification for coarse and fine aggregates from natural sources for concrete (reoi,rd).

( Second revision in 1970 ).llM&hods of test for aggregatu for concrete : Part IV Mechanical proper&.

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I9 1w71* 1970d) Under-layer of cement con-Crete topping in two layers Graded from 12.5 mm and below

1s SIEMDESIONA~ONmm402016125104751.36

TABLE 1 COARSE AGGBBGATE( Chi.r~ 4.2.1.1 )

PERCENTAGE ASSING OR GRADED AGQREGATE OFNOMNAL SIZEr--e- -h--------__4Omm 20 mm 16 mm 125 mm95 to 100 100 - -30 to 70 95 to 100 100 100- 90 to 100 -

- - 90 to 10010 to 35 25 to 55 30 to 70 40 to 850 to 5 oto 10 oto10 0 to 10

- - - -

4.2.1.2 Fine aggregate- The grading of fine aggregate for cementmncrete flooring mix shall be within the limits of one of the two zonesgiven in Table 2. The fine aggregate shall be described as fine aggre-gate of the grading zone into which it falls.TABLE 2 FINE AGGREGATE

IS SIEVE DESIGNATIONmm

104752361.18

600~micron300-micron150-micron

PERCENTAGEBY WEIGHT PASSINO IS SravuC -----.----~~_~_~Grading Zone 1 Grading Zone 2100 10090-100 90-10060-95 75-10030-70 55-9015-34 35-59

5-20 8-30O-10 O-10

4.3 Water:- Water used shall be clean and free from oil, acid, alkali,organic or vegetable matter. Generally potable water will be suitable. Incase of doubt the quality of water should be analysed to ascertain con-formity with 4.3 of IS : 456-l 964*.

*t&de of practice for plain and reinforced concrete ( ~econd~visivn .6


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ls: 2571-197051 DESiGN CONSIDERATIONS5.1 Types of Floor Finish and Thicknesses - The floor finish shall belaid according to any of the specifications given in Table 3, dependingupon the expected load and wear on the floor and the fact whether thetopping is to be laid monolithic with the base or separately on a set andhardened base. In either case special precautions are necessary to ensuregood bond between the topping and the base.

5.1.1 Monolit hic Floor Finish ( Finish Types I and IV) - In case of monoli-thic construction even a small thickness of topping is sufficient because ofstrength imparted to it by the b&se concrete and such type of finish is quitesuitable as a moderately strong and economical floor finish ( finish Type I )with good wearing quality.5.1.1.1 On structural/suspended slabs, monolithic construction offloor finish (finish Type IV ) is fundamentally more reliable form ofconstruction from the point of view of bond development and consequentlybetter wearing properties but this type of construction presents difficultiesin construction if a close surface tolerance is to be obtained; it is difficultto obtain proper levels in the smaller thickness of topping. Moreover asthe finish in such type of construction will be completed much in advanceof the remaining building work it is likely to be damaged or discoloured

due to subsequent building operations; this can, however, be avoided tgsome extent by covering the finished surface with a 75 mm thick layer ofsand which can be removed after all the building operations are over andfloor is ready to be used. Further when the surface of monolithic toppingk damaged, its repairs cause difficulties as there is a risk of either thestructural slab being weakened while picking up the surface for repairs,or the level of floor is likely to be raised to accommodate extra thicknessrequired while repairing the surface with a fresh non-monolithic topping.Another disadvantage in this type of construction from practical point ofview is that the time available on any day to the workmen for laying thefinish monolithic with the structural slab is very much restricted. Theadvantage of monolithic topping is that the thickness required is less thanin case of bonded finish thus reducing the materials and the load on thestructure and the cost. This type of flooring can form a durable andeconomical floor finish provided the limitations given above are taken intoaccount and suitably prQvided for.

5.1.2 Bonded Floor Finish ( Fink Tyfw II, III, V and VI) - In the case ofbonded construction where floor finish is laid separately over a set andhardened base, the topping has to be laid to a greater thickness and themethods of laying have to be adjusted in such a way as to produce goodbond between the topping and the base, failing which the difference incomposition between the base and the topping and the change intemperature and moisture content will cause cracking, curling and

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$912571- 1970warping of the floor finish. The bond between the topping and the basein this type of construction can never be as perfect as in the case ofmonolithic construction and there may be slight lifting of floor finish atcorners of different panels. In case of bonded floor finish laid onstructural slabs, the greater thickness of topping also adds to the weight.of the structure.

5.1.2.1 The advantage of this type of construction is that, as the baseconcrete or structural floor is laid much in advance and topping is laidafter all the building operations are over, there is no danger of surface ofthe floor finish being damaged or discoloured due to other buildingoperations. Where this type of finish is laid on structural slabs a veryclose surface tolerance can be obtained and there is no dilficulty inobtaining proper levels and gradients in the finished floor surfacebecause of greater thickness of topping. This type of finish is alsosuitable where floor finish is to be laid on old concrete or for repairing oldfloor finishes.

5.1.2.2 Where very dense and smooth surface is desired, the toppingin this type of finish can be laid in two layers ( finish Types III and VI ).The under-layer consisting of a leaner mix is first laid separately onhardened base and the wearing layer of very stiff and richer mix, but ofthe thickness smaller than that of the under-layer is bonded to the greenconcrete of under-layer and finished smooth.5.1.3 In case of bonded finish on structural slabs where it is notpossible to obtain proper levels within the thickness of topping, a cushion-ing layer of about 50 to 75 mm thick lime concrete is laid and wellcompacted over the structural slab. Lime concrete layer may also hcnecessary to obtain a level surface over structural floors other than that otconcrete or for embedding fixtures like pipes, etc. This will, however, addto the dead weight of the structure.

5.2 M ix P r o p o r t i o n s - Mix proportions for the lo se concrete and thetopping for different types of floor finish shall 5e as specified in Table 3.NOTE - So far the practice had been to use. 1 : 2 : 4 cement concrete for topping for

bonded finish, but this mix is being increasingly replaced these days by 1 : 21: 3& mixbecause it gives much better work ability and finish.5.3 Du r ab i l ity - Concrete floors possess good durability and resistanceto abrasion and wear depending upon the following factors:a) Choice of aggregate Hard tough aggregate is essential forgood durability as well as abrasionresistance.b) Water-cement ratio Provided the flooring is fully compact-ed, the lower the water-cementratio the greater the durability

and wear resistance; a lower water-cement ratio compatible withworkability is, therefore, essential.8


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IS : 2571- 1970c) Density of flooring

d) Curing

Durability is increased in accordancewith the degree of density of finish,consequently the flooring shall bewell compacted. The staining on thefloor surface that may result fromabsorption of oils is reduced byincreasing the density of floor finish.

Adequate curing is very essential toensure good wear resistance.5.4 Resistance to Attack by Ckemical Reagents - Concrete flooringis slowly attacked by acids, vegetable oils, fats, sugar solutions and variousother agents; prolonged exposure to these reagents will bring about gradualdeterioration.5.5 slipperiness - The slipperiness of concrete flooring depends mainlyupon the surface treatment; when highly polished this type of floor finishis likely to be slippery. A trowel-finished floor is reasonably non-slip.Non-slip surfaces may be obtained by trowelling the floor surface or byproviding non-slip inserts.

5.5.1 Floor finish over ramps, stairs and other simil.ar situations, speci-ally if they are liable to get wet, shall be f inished in chequered pattern tomake them non-slip.5.6 Surface Hardening Solutions - It is not necessary, generally, toapply any further treatment to the cement concrete floor topping butdusting may be reduced by the application of one of the surface hardeningsolutions of sodium silicate, magnesium silica-fluoride or zinc silica-fluorideor proprietary materials consisting mainly of one or more of thesecompounds. These treatments are likely to need renewal at intervals ofone year. Where proprietary materials are to be used, advice should beobtained from the manufacturers. The treatment may be given asdescribed in Appendix A.5.7 Size of Panels -Floor finish shall be divided into suitable panelsso as to reduce the risk of cracking. Size of the panel is governed by thethickness of floor finish, the type of construction ( monolrthic or bondedconstruction ), local conditions of temperature, humidity and the season inwhich flooring is laid. For floor finish laid in exposed situations or in hotand dry climates, the size of the panels shall be smaller as compared to thefloor finish laid in less exposed situations or in cold and humid climates;the size of panels for integral floor finish can be larger than that of floorfinish laid separately on the hardened base. Generally, no dimension of apanel shall exceed 4 m in case of floor finish laid monolithically with thebase concrete and 2 m in case of floor finish laid separately on a hardenedbase; length of a panel shall not exceed 14 times its breadth.

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TABLE 3 REco MMENDED SPECIFICATIONS FOR DIFFERENT TYPES OF - ts

TYPE SUB-BASE

(1) (2)I lhoroughly consoli-dated ground cover-ed with 100 to 150mm well rammed( preferably coarse )sand

IA 100 mm th ick hardcore of dell consoli-dated ary brick orstone aggregateblinded with MO-ORUM (disinteg-rated rock )coarse sand, laYiover well rammedsand filli ng of 100mm thick

IB Stone ballast ( 40mm graded aggre-gates ) mixed withlocally availableyellow or red soil orsoft MOORUMin1 :1 proportion shallbe compacted toabout 300 mmthickness and tho-roughly saturated

CONCRETE FLOOR FINISHESi( Clorucs 5.1, 5.2, 5.9, 8.1, 8.2,8.2.4, 9.1,9.2 and 9.3 )BASE CONCRETE TOPPINOc----TM r L--En&E Mix Proportion Minimum Mix Proportioni Thicknessmm mm

(3) (4) (5) (6)A. Concrete Floor ing Laid Over Ground100

100

Cement concrete1:4:8 (cement:fine aggregate : coar-se (stone aggregateof40 mm and belowby volume )do

20

25

Cement concrete 1 : 2to 3 ( cement : stoneaggregate of size475 mm and belowby volume )Cement concrete1:2:4 (cement:fine aggregate : Co-arse stone aggre-gateofsize 125mmand below by VO-lume )

100 do 20 Cement concreteI:2 to 3(cement:stone aggregate ofsize 4.75 mm andbelow by volume )

SeeFig. 1A. Cementconcrete toppmgshall be laid mono-lithic with the baseconcrete (see also5.1.1 and 8.1)In places such as gm-rages where wheel-ed traffic comes intocontact with theflooring the sub-baseshall have a hardcore over the wellrammed sand filling.The cement con-crete topping shallbe laid monolithic

with the base con-crete (see Fig. 1B)In the regions hav-ing expansive soilslike the black cottonsoil the sub-baseshall be laid as du-cribed ( see Note ).The topping shallbe laid monolithicwith the base con-crete ( ICC ig. 1C )


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T-3 REcoluMEND ED SPBU?'ICATZONS FOR DDWBRBNTTYPBS OF CBMBNT !coBERBTB FLOOR lmulsms-CoRklbit @NCnaTN TOPPINOI cMu P&L7 , * ag??y& Minimum Mix ProportionThicknaumm mm

(3) (4) (5) (6)R. Floor Topping Laid Over Stnsoturul/Suapendad Sl&a

15 Cement concrete1:2to3(cement:stone aggregate ofsize 475 mm andbelow by volume)

V - 25 Cement concrete1 :2*:3f(cement:fine aggregate : co-arse stone _gate ofsize 12aEZand below by vo-lume )

(7)

See Fig. 3. Cementconcreteshall be Ia%:finished _thic with the struc-tural slab. Forthis purposethe topping shallbe laid immedi-ately after the StNC-tural concrete hasstiffened enough(but is still green )to allow for theworkmen to treadover it by placingplanks (see Ulso5.1.1 and 9.1)

See Fig. 4A. Top-ping shall be laiddirectly over thespecially preparedsurface of set andhardened struc-tural slab ( seealso 5.1.2 and 9.2 )


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VI - Under-layer-mfytCOllCRU!6 (cemen t : iin:aggregate : COarsCstone aggregate ofsize 12.5 mm andbelow by volume )

SW Fig. 4B. Undcr-layer shall be laiddirectly over thespecially preparedsurface of set andhardened StRlC-tural slab. Wear-ing layer shall thenbe laid over thegreen surface ofunder-layer andfinished monoli-thic with it ( SMalso 5.1.2 and 9.2 )

M4 VII - 56 to 75 Lime concrete

Wearinglayer-15 Wearing layer-ce-mcnt concrete 1:2to 3 ( cement : stoneaggregate of size475 mm and belowby volume )

same as forVorVI See Fig. 5. Cushion-ing layer of limeconcrete shall belaid over the prepared surface ofstructural /suspend-ed slab. Cementconcrete toppingshall be laid as forV or VI (see also5.X.3 and 9.3).Lime concrete shall


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Up 2571.1970BASE CONCRETE

CEMENT CONCRETE TOPPINGLAID MONOLITHICALLY WITHTHE BASE CONCRETE

L SAND F ILLING1A WITHOUT HARD CORE SUB-BASEMAR0 CORE OF DRY BRICX OR STONE BALlASBASE CONCRETE

CEMENT CONCRETE TOPPING LAID

18 WITH HARD CORE SUB-BASEEMENT CONCRETE TOPPING

BASE CONCRETE 20

%%%-E BALLAST t4?i?6 WITH lr VELLOW OR RED SOIL OR e CONSOLIOATEOSOFT MOORUM GROUND1C SUB-BASE FOR REGIONSHAVlNG EXPANSIVE SOILAll dimenaiom in millimetrca.

F r o . 1 MONOLITHIC LOORF INISH OVER GROUND14


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Br2S71-1970WEARING LAYER OF CEMENTCONCRETE MIX 1:2 TO 3FINISHED MONOLITHICALLYWllH UNDER-LAYER

L CONSOLlOAlEO GROUND -ISAND FILLING SAND FILLING

BASE CONCRETE 1BASE CONCRETE2A Topplng Laid in Single Layer 2B Topping Laid in Two Layers

FIG. 2 BONDED FLOOR FINISH OVER GROUNDCEMENT CONCRETE TOPPINGFINISHED MONOLITHICALLYWITH THE STRUCTURAL SLAB 1

15mm

LSTRUCTURAL SLABFIG. 3 FLOOR FINISH AID MONOLITHICALLY WITH THE

STRUCTURAL SL.ABWEARING LAYER OF CEMENTCONCRETE MIX 1:2 TO 3FINISHED MONOLITHICALLYWITH UNDER-LAYER

m

L STRUCTURAL SLAB J hNDER-LAYER OFCEMENT CONCRETEMIX 1:3:64A Toppin g Laid In Single Layer 4B Toppin g Laid in Two Layers

FIG. 4 BONDED FLOOR FINISH OVER STRUCTURAL SLAB15


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I S t 2 5 7 1 - 1 9 7 0

CEMENT CONCRETE TOPPINGLIME CONCRETECUSHIONING LAYER I- 25

LSTRUCTURAL SLAB

5A TOPPING LAID IN SI?lGLE LAYER

-CEMENT CONCRETE TOPPING-UNDER-LAYER OF

CEMENT CONCRETE

CUSHIONING LAVER58 TOPPING LAID IN TWO LAYERS

All dimensions in millimetrcs.FIG. 5 FLOOR FINISH N STRUCTURAL SLAB LAID OVER CUSHIONING

LAYER ix LYME CONCRETE

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IS t 2571.19705.7.1 The joints in the floor finish shall extend through the borders and

skirtings. If the skirting is laid monolithic with the flooring, a borderof about 300 mm width must be provided alround the floor. The widthof border provided around the floor when the skirting is not monolithicwith floor finish shall not exceed 450 mm.5.7.2 Construction joints between bays of the floor finish should beplaced over any joints in the base concrete.

5.8 Protection Agahst Dampness - The layer of sand provided underthe base concrete will generally serve the purpose of damp-proofingrequired for ordinary floors under normal conditions. However, in moresevere conditions, where it is expected that the dampness may find its wayon the top of the floor in the course of usage of floor, a more effectivedamp-proof treatment shall be given underneath the floor by either of themethods given bdow:

a) Laying the base concrete in two layers of thickness not less than75 mm each and painting the top of the lower layer with twocoats of hot bitumen of the industrial grade 85125 conforming toIS : 702-1961* applied at the rate of ,1*5 kg/m2. The surface ofthe lower layer shall be finished smooth while laying the concreteso that bitumen can be applied uniformly. The bitumen shall beapplied after the concrete has set and is sufficiently hard.b) Sandwiching a waterproofing membrane, such as bituminous feltin the base concrete laid in two layers of thickness 75 mm each,The surface of the lower layer shall be finished smooth whilelaying the concrete so as to provide an even surface and thusprevent damage to the surface of waterproofing membrane.

5.8.1 Where. it is expected that the dampness may find its way from thesurrounding walls,. the same shall also be effectively damp-proofed up to atleast 150 mm above the level of the base or sub-floor, and the damp-prooftreatment below the floor shall be extended over the walls. Basementfloors shall be damp-proofed according to recommendations of IS : 1609-1966t.5.8 Finish Over Stairs- The mix for finish over stairs shall be the sameas for topping specified in 5.1 ( see aho Table 3 ). Risers shall be finishedwith the minimum thic ness necessary td give an even surface to thestructural concrete. For this purpose, 6 mm thick mortar finish willgenerally be sufficient, but thickness up to 10 mm may be provided wherethe surface of the structural concrete is found to be very uneven. Thick-ness of the finish at treads shall be not less than 20 mm for monolithicfinish, and not less than 40 mm for finish laid over the Ylardenedconcrete.-- -*Specification for industrial bitumen ( revised).t&de of practice for laying damp-proof treatment using bitumen felts (first rruirien).

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IS I 2571.1970 fi6. PR OGRAMME OF WO RE IN RELATION TO FLOOR FINI SH6.1 Before the flooring work is taken up, the following operations shouldhave been completed:a>

WThe completion of all pieliminary operations, such as laying ofservices affecting the schedule of commencement and completionof flooring; andPlastering all the inside walls, ceilings and outside walls, andfixing of door frames in place..be completed. All heavy work in the room may

6.2 The sub-floor or base shall be finished to a reasonably true plane surfaceto a level which is lower than the level of the finished floor by the depthoccupied by the thickness of the topping. The desired slope may beprovided, where possible, in the base or sub-floor.6.3 Before the floor finish work is started, all points or level for the finishedsurface shall be marked out. Wherever slope in finished floors is desired,points of level and outlets shall he correctly marked and outlet openingsmade beforehand.

7. PREPARATORY WORK7.1 Handling and S t o r a g e o f Materials - Clean and dry storage shallbe provided at the site for all the materials. Cement shall not be storedin open. The materials shall be stored in accordance with IS: 4882-1967*.7.2 Mixing of Materials

7.2.1 The aggregate and cement shall be thoroughly and efficientlymixed. Mixing shall be done using a mechanical mixer. Manual mixingmay be permitted when Lhe quantity of concrete mixed is small. Theconcrete shall be as stiff as possible and the amount of water added shallbe minimum necessary to give just sufficient plasticity for laying andcompacting. For improving the workability of the mix, thorough mixingrather than addition of more water shall be resorted to. Thorough+nixingwill improve the workability even for a very stiff mix and thus facilitatehetter finish. High water-cement ratio will increase the drying shrinkageand decrease the strength, water-tightness and abrasive resistance of theconcrete.7.2.2 The mix shall be used in the work within half-an-hour of theaddition of water for its preparation.*Recommendations on stacking and storage of construction materials at site.

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IS t 2571- 197Q8. LAYING CONC RE TE F LOOR ING ON GROU ND8 .1 F l o or F i n i s h L a i d M on o l it h i ca l ly w i t h t h e B a s e C o n c r e t e( F in i sh Types I , IA and IS , Tab le 3 )

8.1.1 Preparation ?f Sub-base8.1.1.1 The ground or earth filling shall be thoroughly compacted sothat there are no loose pockets left anywhere in the whole area. This shallthen bc covered with clean sand well consolidated to a thickness of not lessthan 100 mm. Great cart is necessary in the preparation of the sub-base,as a settlement in the sub-base may cause the failure of the whole floor.8.1.1.2 In situations, such as garrages where wheeled traffic comes

into contact with the flooring, sub-base shall consist of well compactedsand layer of 100 mm thick and an additional 100 mm thick wellcompacted hard core of dry brick or stone ballast ( 40 mm size ) blindedwith MOORUA4 ( disintegrated rock ) or coarse sand.8.1.1.3 In the cast of expansive soils, like black cotton soil, stoneballast ( 40 mm graded aggregates ) mixed with locally available yellow orred soil or soft MOORUM in 1 : 1 proportion shall bc compacted to about300 mm thickness and thoroughly saturated with water. This surfaceshould bc further covered with another 200 mm thick layer of soft

MOORUM or cinder or sand and compacted properly before laying thebase conr-ete. Special care is necessary in consolidation of the ground asotherwise the settlement of sub-base may cause cracking of the wholefloor.

8.1.2 Laying the Base- The area to be paved shall be divided intosuitable panels keeping in view the limits specified in 5.7. This shall bedone by fixing screed strips, the depth of which shall be equal to thecombined thickness of the base concrete and the topping. Before beinglaid in position the screed strip shall preferably be coated with a thick coatof lime wash so as to prevent them from sticking to the concrete depositedin the panels.

8.1.2.1 Before placing the base concrete, the sub-base shall be pro_perly wetted. The concrete shall then be deposited between the screedstrips, thoroughly tamped and the surface scrccded uniformly below thedesired finished grade of flooring to accommodate the required thickness oftopping. Any slope desired in the floor finish shall be given in the baseconcrete. The surface shall not be finished smooth but kept rough toprovide adequacc- bond for the topping.

8.1.3 Laying the Toppiq - On the clean,. srecn surfat e of the baseconcrete, the topping shall be placed in posltlon as soon as possible butgenerally not later than tmw or three hours of laying the ba$e coucr(tedeprnding upon the temperature and the atmospheric collditions. 1hCbasz concrete at the time of laying the topping shall be still green but

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'IS:25711970sufficiently firm to enable the workmen to work over it by placing plankson its surface.

8.1.3.1 The concrete mix for the topping shall be deposited on thebase concrete in the screecl strips already laid and thoroughly compactedto the finished thickness. Glass or aluminium strips may be provided foreffective separation of panels and to provide straight edges and corners forthe panels where good workn-znship is required. The mix for the toppingshall bc stiff enough to prevent accumulation of any excess water orlaitance on the surface. If water or laitance ri\es to the surface whenconsolidatin:: ( whit-II indicates that too much of water has been used in thepreparation of co:l:~t~ ) the concrete should preferably be scraped andreplaced by a fi-csll u:lx. If it is desired to absorb surplus water for anyreason, it should IX mopped up; it should on no account be absorbed byspreading dry crmcnt. The toppi,g shall then be floated with a woodenfloat to rencler the surface even and after the surface is slightly hardened,it shall IX finished smooth as described in 8.1.3.2.

8.1.3.2 Finishiq the surface - r2fter the concrete has been fullycompacted it shall bc finished by trowelling or floating. Finishing opera-tions shall start shortly after the compaction of concrete and shall bc spreadover the period of one to six hours depending upon the temperature andatmospheric conditiona. The surface shall be trowelled three times atintervals so as to produce a uniform and hard surface. The satisfactoryresistance of floor to wear depends largely upon the care with whichtrowelling is carried out. The object of trowelling is to produce as hardand close knit a surface as possible. The time interval allowed betweensuccessive trowelling5 is every important.just sufficient troweilili Immediately after laying only:,y shall be done to give a level surface. Excessivetrowelling in the ca&sr stages shall bc avoided as this tends to work a layerrich in cement to tile surface. Sometime, after the first trowelling, theduration depcncliug upon the tcmpcrature, atmospheric conditions and therate of set of cement u$ed, the surface shall be retrowelled to close anypores in the smfacc, a~1 to bring to surface and scrap off any excess waterin concrete or laitance ( it shall not be trowelled back into the topping).The final trowclliua shall IX do:le well before the concrete has become toohard but at sucll a timr that considerable pressure is required to make anyimpression on the surface. Trowelling of a rich mix of dry cement and fineaggregate on to the surface shall not be permitted.8.1.4 The base concrete and the topping shall be laid in alternatepanels, the i:ltermcdiate panels being filled in after one to t\ro daysdependin,? upon the temperature and atmospheric conditions. Thescreed strip? sholl!cl IX removed the next day after the concrete has been

deposited in t!l;, panels and the e?ges of panels shall be examined for anyhoneycombing or undulation which, if found, shall be repaired straightand smooth by cement mortar. If the intermediate panels are not to befilled the next day the screed strips shall then be cleaned and put back20


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1St2571-1970against the edges of panels till the concrete in the alternate panels is to bedeposited. When the concrete is being deposited in the alternate panelsthe screed strips shall be removed. When the concrete is being compactedin new panels, care shall be taken to avoid damage to the panels alreadylaid. If glass or aiuminium strips are provided for effective separation ofpanels the base concrete and the topping may be laid in all the panelssimultaneously.8.2 Floor Finish Laid Separately on Hardened Concrete Base( Finish Type II, Table 3 )

8.2.1 Preparation of Sub-base - The sub-base shall be prepared as des-cribed in 8.1.1.1,8.1.1.2 and 8.1.1.3.8.2.2 Laying the Base Concrete - The base concrete may be deposited inthe whole area at a stretch. Before placing the concrete the sub-base shallbe properly wetted and rammed. The concrete shall then be depositedbetlveen the forms, where necessary, thoroughly tamped and the surfacefinished level with the top edges of the forms. The surface of base concreteshall be left rough to provide adequate bond for the topping. Two orthree hours after the concrete has been laid in position, the surfice shall bebrushed_$th a hard brush to remove any scum or laitance and sweptclean so that the coarse aggregate is exposed.8.2.3 Laying the Topping-Bet&e the operation for laying the topping

1s Started the surface of base concrete shall be thoroughly cleaned of alldirt, loose particles, caked mortar droppings, and laitance, if any, byscrubbing with coir or steel wire brush. Where the concrete has hardene,dso much that roughening of surface by wire brush is not possible, the entiresurface shall be roughened by chipping or hacking. Before laying thetopping, the surface shall b c soaked with water, at least for twelve hoursand surplus water shall be removed by mopping immediately before thetopping i5 laid in position.8.2.3.1 The scrzed strips sha!l be fixed over the base concrete dividingit into suitable panels as recommended in 5.6. The screed strips shall be

so arranged that the joints, if any, in the base concrete shall coincide withthe joints in the topping. Before placing the concrete mix for topping,neat cement slurry shall be thoroughly brushed into the prepared surfaceof the base concrete just ahead of the finish. The topping shall then belaid, very thoroughly tamped, struck off level and the furface floated witha woode:i float. The surface shall be tested with th? straight-edge andmasons spirit-level to detect any inequalities in the surface which, if any,shall be made .good immediately. The finish shall bc laid in alternatepanels as dcscrlbed in 8.1.4 for topping laid monolithic with the baseconcrete.8.2.3.2 Finishing the surfke - The surface shall be fininshed as givenin 8.1.3.2.

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IS : 25711197Q8.2.4 Laying the To#ting in Two Lawyers Where the topping is to be l&din two layers to obtain very smooth and dense finish ( see Finish Type III,

Table 3 ), the sub-base, base concrete and under-layer of topping shall belaid as described in 8.2.1 to 8.2.3 with the exception that the surface of theconcrete in the under-layer of topping shall not be finished smooth with atrowel but left rough after tamping it and levelling it with screed board.8.2.4.1 The top 15 mm thick wearing layer of mix 1 : 2 to 3 cementconcrete ( depending upon the quality of finish and abrasive resistancedesired ) of consistency stiffer than that of under-layer concrete shall thenbe immediately laid over the rough but green surface of under-layer, andthoroughly tamped, struck off level, and the surface floated with woodenfloat. The surface shall then be tested with a straight-edge and masonsspirit-level to detect any undulation in the surface which, if any, shall bemade good immediately. The surface shall then be finished smooth inaccordance+ with 8.1.3.2.

9. LAYING F LOOR TOP P ING ON SUSP ENDE D SLABS9 .1 F l o or T o p p i n g L a i d M on o l it h i ca l ly w i t h t h e S t r u c t u r a l /S u s -pen de d S lab ( F in i sh Type IV, Tab le 3 )

9.1.1 The form-work for structural slab shall be erected to the finishedthickness of floor finish. Structural, concrete shall be deposited in the.forms, thoroughly consolidated and surface finished below the top edge ofthe form to accommodate the required thickness of the topping_ Any sloperequired in the floor finish shall be given in the structural concrete itself,and any laitance or scum shall be brushed away from thr surface ofconcrete when it is still green. The surface shall not be finished smooth butkept rough to provide an adequate bond for the topping. 4

9.1.2 On the green surface of the str&tural concrete, topping shall beplaced in position immediately after the structural concrete has stiffenedenough ( but is still plastic ) to allow for the workmen to tread over it byplacing planks. Laitance and foreign matter, if any, shall hc removedbefore the topping is placed in position. The topping shall bc thoroughlycampacted and screeded to the finished grade. The mix for the structuralconcrete as well as the topping shall be as stiff as possible consistent withworkability so as to prevent accumulation of excess of water or laitance onthe surface. The topping shall then be floated with a wooden float torender the surface even. After the surface is lightly hardened, it shall befinished in accordance with 8.1.3,2.9.2 Floor T op p i n g L a id D ir e c t ly o ve r t h e H a r d e n e d S t r u c t u r a l/S u s p e n d e d S la b ( F i n i s h T y p e s V a n d VI , T a b l e 3 )

9.2.1 Preparation of Surface of Structural/SusperzdedSIab - When the t opp i r l gis to be laid separately but directly over the structural slab without any22


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IS : 2571.1970cukhionihg layer, the structural concrete, 3 to 4 hours after its laying in theforms, shall be thoroughly brushed with a coir or steel wire brush toremove any scum or laitance and swept clean to expose the coarse aggre-gates and leave the surface rough.9.2.2 Laying To#Gng -Before the operation of laying the topping isstarted the surface of structural slab shall be thoroughly cleaned of thedirt, loose particles, cake mortar droppings and laitance, if any, by scrub-bing with coir or steel wire brush. Where the concrete has hardened somuch that roughening of surface by wire brush is not possible, the entiresurface shall be roughened by chipping or hacking.

9.2.3 The screed strips shall then be fixed over the structural slabdividing it into suitable panels as recommended in 5.7. Immediatelybefore depositing the concrete for the topping, neat cement slurry shall bethoroughly brushed into the prepared surface of the structural slab, justahead of the finish. The topping shall then be laid, thoroughly tamped,struck off level and surface floated with a wooden float. The surface shallthen be tested with a straight-edge and masons spirit-level to detect anyinequalities and undulations in surface which, if any, shall be made goodimmediately, The finish shall be laid in alternate panels as describedin 8.1.4 and other laying and finishing operations shall be done as in 8.2.3and 8.2.4 depending upon whether the topping is to be laid in single ortwo layers.9.3 Floor T o p p i n g L a i d o y e r C u s h i o n i n g L a y e r o f L im e C o n c r e t e(Table3)

9.3.1 Preparing the Sub-Joor- Before laying the lime concrete, the surfaceof sub-floor shall be thoroughly cleaned of dirt, loose particles and laitance( in case of RCC slabs ) by scrubbing with steel wire brushes. The surfaceshall then be thoroughly cleaned and soaked with water overnight andsurplus water removed by mopping immediately before lime concreteis laid in position. On the clean damp surface of sub-floor, lime concreteshall then be evenly spread between forms, if necessary, thoroughlytamped and levelied. In the preparation and laying of lime concrete therelevant provisions of IS : 2541-1965* shall, as far as possible, be followed.9.3.2 Laying the Top&kg - Before laying the topping, surface of limeconcrete shall be thoroughly cleaned and prepared as recommended forbase concrete in 8.2.2 and 8.2.3. Immediately before spreading theconcrete for topping, the surface shall be brushed with a thin layer of neatcement slurry. The topping whether in single or two layers shall then belaid as given in 8.2.3 and 8.2.4.10. FLOOR FINgSH OVER STAIRS10.1 Risers- After the structural concrete has set, the form-work forrisers of stairs and landings shall be struck, laitance removed and the--*code of practice for use of lime concrete in buildings.

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IS : 2571~ 1970surface of risers left rough to provide adequate bond for the finish. Therisers shall then be finished with 1 : 3 cement mortar ( see 5.9 ).10.2 T r e a d s - Finishing to landings and stair treads shall be carried ovtas described for flooring in 9.1 and 9.2.I l. CURING11.1 Immediately after the flooring surface is finished it shall bc protectedfrom rapid drying by erecting barriers against wind or draught and strongsunlight. As soon as the surface has hardened sufficiently to preventdamage to it, it shall be kept continuously moist for at least fifteen days bymeans of wet gunny bags, 50 mm thick layers of dxmp sancl spread overthe surface or pooling water on the surface. During this period theflooring shall not be exposed to any traffic. Regular traffic on the floorshould be allowed only after 28 days.12. INSP ECTION AND TESTING12.1 Adh es ion to th e Ba se o r Su b-floor -The adhesion betweentopping and the base may be examined by tapping the surface \\ith the endof a rod or a hammer. A hollow sound indicates poor adhesion.12.2 Loss of adhesion does not necessarily mean that the floor finishis unsuitable except when it is accompanied by visible curling ot the edgesof panels or cracks. Occasionally there is no lipping but the panel edgesare noticeably higher than the centres of panels. In these circumstancesthe flooring may deflect and break under the loads likely to be imposed inuse and must be considered unsuitable. Where the flooring is consideredto be unsatisfactory, the topping concrete and any loo>e concrete inthe base ,concrete shall be cut out and the base concrete keyed sufici-ently to allow a sound renewal to be made. It is prcfcrabic a;ld \villprobably be necessary, owing to the possible loosening of adjacentwork by vibration, to renew the whole of the panel or paltcls wheresuch defects occur.

APPENDIX A( Clause 5.6 )SURF ACE TREATMENT TO CEMENT CONCRE TEFL O O R T O PPI N G

A-l. CLEANING THE SURFACEA-l.1 The top surface of the concrete should bc clean ant1 free fromgrease or oil to enable the hardening solutions to pcnctrate. Sweeping to

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removeust and dirt may be adequate only in some cases of new floorsand additional cleaning may be necessary. The top surf&e shall be wettedwith water and scrubbed with coir or steel wire brush and thoroughlycleaned by washing with clean water. The floor should be allowed to dryso that the hardening solution can be absorbed into the surface.

Ar2. TREATMENTSA-2.1 Sodium Silicate-A olution containing one art by volume ofsodium silicate and four to six parts of water shoulx be spread evenlyover the concrete top surface with a mop or soft brush. Any excessmaterial should be wiped off and the floor allowed to dry. After thefloor has been washed with clean water, a second coat, containing onepart of sodium silicate to three or four parts of water, should be applied,and this should be allowed. to dry similarly. A third coat may be appliedafter washing if the floor .isstill porous. After drying, the floor should bewashed with hot clean water. Effective results are obtained if the treat-ment is appiied seven to ten days after the end of curing.A-2.2 Silk-FluorideThe crystals of magnesium s&o-fluoride or ofzinc silica-fluoride should be dissolved in water at the rate of Cl g/cm* forthe first coat and @2 g/cm for subsequent coats. Three coats are usuallyapplied at 24 hour intervals. .There IS no need to wash the top surface oithe floor between coats, butthe final treatment. it is advisable to wash with clean water afterA-2.5 Dry&g OH rpd Surface Sealerm -Drying oils, either neat orthiied with turpentiue or white spirit, or surkce sealer+ may be appliedto the top surf&e by brushing. Any excess should be wiped off about twohours tier applicatson.112.4 Calcium chloride shall not be used with high ahuninacement.

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2571-COP for laying insitu CC flooring