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IS 6494 (1988, Reaffirmed 2010): Code of Practice for

Waterproofing of Underground Water Reservoirs and Swimming

Pools (First Revision). UDC 621.642.37 + 725.74 : 699.82

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( R e a f f l f i ~ ~ d l 9 Q O 10)Indian Standard ( Reaffirmed 2000 )

CODE OF PRACTICE FORWATERPROOFING OF UNDERGROUNDWATER RESERVOIRS AND SWIMMING POO.LS

G.. "

(First Revision)Second Reprint OCTOBER 1997

UDC 621'642'37 + 725'74: 699'82 .

@ Copyright 1989BUR E A U 0 ' 1 N D I A N S TAN DAB. D SMANAK BHAVAN. 9 BAHADUR SHAH ZAlAR MARC

NEW DELHI 110002Jun, 1989

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IS : 6494 - 1988Indian Standard

CODE OF PRACTICE FORWATERPROOFING OF UNDERGROUNDWATER RESERVOIRS AND SWIMMING POOLS

(First Revision)O. FOR E W 0 R D

0.1 This Indian Standard (First Revision) wasadopted by the Bureau of Indian Standards on1 September 1988, after the draft finalized by theWaterproofiing and Damp-proofiing SectionalCommittee had been approved by the CivilEngineering Division Council.0.2 During the construction of undergroundwater reservoirs and concrete swimming p ~ l s , itis essential to ensure the water-tightness of theresulting structures so that the flow of water frominside the structure to outside, and the infiltration of water from the surrounding soil into thestructure are effectively prevented. This standardis intended to provide guidance to the engineers.contractors and others engaged in buildingactivity in the methods to be adopted for theconstruction of water-tight underground reservoirs and swimming pools.0.2.1 This standard lays down provisionsrelating to membrane type of waterproofingincluding certain other provisions relating toconstruction technique, the quality o f material,

1. SCOPE1.1 This standard lays down the procedure to befollowed and the precautions to be taken duringthe constr-uction of underground water reservoirsan d swimming pools So as to ensllre the watertightness of the resulting structure. Method ofmaintenance and rectification of defects noticedduring the construction are also covered in thisstandard.2. REQ,UIREMENTS OF STRUCTURE,DESIGN AND CONSTRUCTION DETAILS2.1 Requirements for Swimming Pools andUadergroundReservoirs - These st ructuresshould be built so as to compJy with the requirements of the best practice pertaining to reinforced concrete, plain concrete or such other form ofconcrete construction as may be employed [seeIS : 3370 t Part 1 )-1965]. The requirements

Code of practice for concrete structure. for the storageof liquids: Part 1 General requirements.

etc, which are important from the point of viewof overall waterproofing and which need to betaken into consideration by those entrusted withcivil construction work.0.3 Th e standard was published in 1972 an d therevision of this standard has been taken up toincorporate further changes necessary in view ofthe revision of various standards referred to inthis standard. In this revision the detail procedure to be followed in carrying out chemicalinjection treatment has been added.0.4 For the purpose of deciding whether aparticular requirement of this standard is complied with, the final value, observed or calculated,expressing the result of a test or analysis, shall berounded off in accordance with IS: 2-1960*.Th e number of significant places retained in therounded off value should be the same as that ofthe specified value in this standard.

$Rules for rounding off numerical values ( revised).

laid down under 2.1.1 to 2.1.9 shall also be takeninto consideration.2.1.1 Suitable precautions shall be taken toa void cracks an d leakages resul ting from thefollowing:

a) Movements due to shrinkagf' an d creep,b) ~ f o v e m e n t s due to variation of temperature and humidity,c) Movements due to dissipation of heatgenerated by the concrete in the process ofhydration,d) Damage to the concrete by the e r ~ o l a t i o nof chemically aggressive liquids from outside,e) Damage due to uneven settlement of fouudations,f) Cracking of concrete caused by rusting of

bars, andg) Hydrostatic uplift force.

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IS I 6494 19882.1.2 Construction joints should be set at rightangles to the general direction of the member( see Fig'. I ) . The position an d arrangement ofconstruction joints should be determined at thedesign stage and indicated on the drawings.Consideration should be given to the limitingnumber of such joints and to keeping them freefrom possibility of percolation ( set .5.5). Thesurface-film of the first-placed concrete shouldpreferably be removed while the concrt'te is stillgreen to expose the aggregate and leave a soundirregular surface. This m.ay be effected. byspraying with water or aI r and water, aSSistedby light brushing, where necessary. If the concrete has been allowed to harden, it will benecessary to achieve the desired surface by hacking the whole of the surface, care being takento avoid damaging the a g g r e ~ a t e .

2.1.2.1 While the remainder of the concretesh()uld be kept continuously wet, curing of thejoint SUI face may be suspended a few hoursbefore concreting is to .be resumed so as topermIt no more than s u p e r f i c i ~ l dr.ying of thejoint surface Just before concretmg IS resumed; , h ~ roughened joint surface should be thoroughlycleaned an d made free of all loose matter, pre .ferablY without rewetting, and then treated witha thin layer of cement grout or cement-sandmortar worked well into the surface. The ratiosof sand to cement, an d water to Cement in thisgrout or mortar should not exceed those in newc,oncrete. Special care should be taken to avoidsegregation of the concrete along the joint planeand to obtain thorough compaction.

2.1.2.2 Alternatively, for horizontal joints,the layer .of grout or mortar ma y be omitted,provided that the workability of first batches ofconcrete placed in contact with the joint isslightly increased.2.1.3 The concrete mix proportions should beso designed as to produce a concrete from theInaterials available:

a) which has a workability to ensure that,with the means available, it ca n be satisfactorily placed in the formwork andcompacted without risk of segregation,honeycombing or bleeding; an d

b) which is sufficiently impervious to wateran d non-porous.2.1.3.1 Th e directions given in 3 of IS : 3370(Part 1)-1965 ma y be followed while designing

th e concrete mix.2.1.4 The permeability of any uniform thoroughly compacted concrete of given mix propor .tions is very largely dependent on its water"cement ratio. While an increase in this ratiowould lead to an increase in the inherent permeability, the consequences of reducing thewater-cement ratio of a mix with a given cementcontent, that is, failure to achieve complete compaction of the drier mix, are lik-ely to be muchmore serious. For a given mix made with particular materials, there is a lower limit to thewatercement ratio which ca n be used economically on anyone job. I t is essential to select arichness of mix compatible with the availableaggregates, whose particle shape and gradinghave an important bearing on the workabilitywhich must be suited to the means of compaction s*cted. Suitable additives m-ay be addedto m a ~ concrete dense an d workable. Efficientvibrating equipment should be employed forcompating the concrete.

2.1 1 In practice, it is usmllly c o n \ ~ e n i e n tparticularly when dealing thin with congestedreinforced sections, to specify a cement contentsufficiently high to ensure that thorough c o m p a c ~tion is in fact obtainable with the means availablewhilst maintaining a sufficiently low watercement ratio. In thicker sections, where areduction in cement content may be desirableto restrict the temperature rise due to cementhydration, a lower cement content is usuaUypermissible, partly because the overall permeability of the section is reduced by the greaterthickness and partly because the less congestedconditions may permit thorough compaction ofa somewhat drier mix.

2.1.5 Concrete should beCuring has an important properly cured.influence on the*Code of practice fot' concre te structures (or the storaleof liquids: Part 1 General requirements.

PREPARED JOtNTSURFACE

FIG. I A TYPICAL CONSTRUCTION JOINT2

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permeability of concrete and i t is necessary tokeep the concrete moist, particularly during thefirst few days.

2.1.6 The permi,sible stresses in concrete an dsteel shaI I be accord ing to th e recoIDrrlendationsgiven in 3.3 and 3.4 of IS : 3370 (Part 2)-1965*.

2.1.7 Slabs in contact with water shall bedesigned in accord alice with the provisions of3.3.1 of IS : 3 ~ 7 0 (Part 2)-1965,

2.1.8 To reduce sh;inkage stresses as fa r aspossible, there should not be I e ~ s than 0'3 percentof steel in any direction.2.1.9 I n long walls, it is recom-mended thatth e walls be divided into sections not more than15 m long with a gap of about 30 cm left betweensections so that the shrinkage in the long sectionsmay occur as far as possible before the gaps are

concreted, an d the longer this ca n be deferred,the better. The use of carefully rebated jointsis imperative at these construction joints.2.2 Reqll i rements for Underground WaterReservior Only

2.2.1 To avoid temperature changes as far aspossible, the reservoirs may, with advantage, bebuilt partly into the ground so that the soil isavailable to cover th e roof, if necessary, an d toform embankments on the outside so as to enclosethe reservoir completely in a covering of earth.Special precautions should be taken to guardagainst evaporation an d the movements arisingfrom extremes of temperature before the coverin g is made.

2.2.2 The permissible stress in steel reinforcement shall be governed by the provision of 3 .4.2of IS : 3370 (Part 2)-1965*.2.2.3 Lapping of reinforcement in circulartanks should be so arranged that not more than

25 percent of the bars are jointed at anyonevertical section.

2.2.4 If the reservoir was partly undergroundand partly above ground -in the portionexposed to atmospheric condhif)ns, there shouldno t be less than 0'3 percent of steel in eitherdirection.3. MATERIALS3.1 Cement - Portland cement conforming toIS : 269-1976t or Portland blastfurnace slagcement conforming to IS : 455-1 976t or PortlandpozzoJana cement conforming to IS : 1489-1976shall be used.

Code of practice for concrete structures for the storageof q u i d ~ : Part 2 Reinforced concrete structures.tSpecification for ordinary and low-heat Protlandcement ( third rel'is;on ).~ S p p . c i f i c a t i o n for Portland slag cement ( third revision ),SSpf'cification for Portland pozzoJana cement ( second,lDis;on).

3.2 Aggregatesa} The aggregates should not have an absorption greater than 2 percent, as measuredin accordance with 2 of IS : 2386 (Part 3)0

1963* b) GradingI) The grading should be such as to produce a concrete with the specified pro

portions and consistency and one thatwill work readily into position withoutsegregation an d without the use of anexcessive water content, an d can bereadily compacted into a dense impervious mass.

2) Fine aggregate should be in accordancewith Table 4- of IS: 383-1970t (allzones).3) The maximum size of coarse aggregateshould be as large as possible, butlimited to the I ~ a s t of the followingdimensions:

i) one quarter of the smallest distancebetween the opposite faces of th esection,ii) fi ve millimetres less than th e minimum cover to the reinforcement,an d

iii) five millimetres less than the cleardistance between the main reinforceing bars.

3.3 Water - Water shall be free from dele.terious materials, reasonably clean an d from asource approved by the engineer.3.4 Steel - Steel reinforcement shaH complywith the requirements of IS : 432 (Part 1)-1982t.IS : 432 (Part 2).1982 or IS : 1786198511.3.5 Bitumen Felt - It shall conform to Type 3,Grade 2 of IS : 1 3 2 2 - 1 9 8 2 ~ and Type 2, Grade2 of IS : 7193-1974**.3.6 Bitumen Mastic - I t shaH conform toIS : 5871-1970tt

Methods of test for aggregates for conCrete: Part 3Specific gravity, density Voids) absorption and bu1kinB.tSpecification for coarse and fine aggregates frOIDnatura) sources for concrete ( second revision ).~ S p e c i f i c a t i o n for mild steel and medium tensile steelbars and hard-drawn s t ~ e l wire for concrete reinforcement:Part 1 Mild steel and medium tensile steel bars ( "'irtlrevisiorl ).Specification for mild steel and medium teasile steelbars an d hard-drawn steel wire for concrete reinforcement:Part 2 Hard-drawn steel wire ( thi,d remsion ).IISpecification for high strength deformed steel ba n an dwire for concrete reinforct:ffif'nt ( third revisitm ).

~ r S p e c i f i c a t j o n for bitumen felts for waterproofiug an ddamp-proofing ( third rems;on ). $GJass fibre hase coal ta r pitch an d bitumen felts.ttSpecification for bitumen mastic (o r tanking aDddamp-proofing (first revision ).

3

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IS -I 6494 19884. WATERPROOFING TREATMENT4.1 General Features - The swimming poolsand underground water reservoirs have to bemade proof against leakage or seepage of wateras follows:

a) From inside the structure to the surrounding ground, andb) From the surrounding ground towards theinside of the structure.

4.1.1 It shall be borne in mind that the practice -of using concrete, not in itself watertight,and placing too much reliance on the waterproofing measures is not desirable. Concreteshould be watertight in itself and the waterproofiing methods should be looked upon asadditional safety devices.4.2 Preventive Mea-sure for Reduction ofSurface Water Entering into AdjacentGround - Where possible, th e grounds shouldslope away from the structure for a distance ofabout 3 m to divert the surface ru n off and toprevent water from standing near or againstthe side walls. The surfaces near the side wallsshould preferably be paved. On sloping -sites,it would -be desirable to construct a-cut-off landdrain on the high side to lead water around th estructure to a lower level.4.3 The ground water shall be prevented fromremaining in contact with the side walls or theflooring for long periods by installing a systemof drainage around the foundation of the structure or beneath the floor or both together. Theprovision of drains around the structure near thefoundation level is recommended for any sitewhere the ground water table is likely to risevery much above the foundation level. Thesedrains should be graded to an open out1et orstorm water sewer or to a sump located in thepremises where pumps of suitable capacityshould be provided to pump ou t the water asfast as it gets coHeeted.4.4 Waterproofing Treatment - For preventing the ground water fronl percolating throughthe flooring the waterproofing/damp-proofingtreatment indicated in 4.4.1 to 4.4.7 may begiven.

4.4.1 After Jaying the levelling course of Jeanconcrete and allowing it to harden for at least48 hours, waterproofing membrane should bespread 'over it, care being taken to provide suitable overlaps and care should be taken to prevent-any damage to the membrane.

4.4.2 If bitumen felt is used for the dampproofing treatment, it shall conform to IS: 1322-1982*. The damp-proofing treatment shouldbe given in accordance with the recommendations given in IS : 1609-1976t.

.Specification for bitumen felts for waterproofing anddampproofing ( third revision ).tCode of practice for laying damp-proof treatmentusing bitumen felts ( second revision).4

4.4.3 If bitumen mastic is used for the damp .proofing treatment, it shall conform to IS : 5871-1970*.4.4.4 .The damp-proofing treatment may alsobe earned out In accordance with IS : 9918-1981 t.4.4.5 The treatment mentioned in 4.4.1, 4.4.2or 4.4.3 should be covered over with at least50 m ~ thick sand cement screed using 1 : 3 mixand Integral waterproofing compound in prescribed proportions. The surface or the screedshould be levelled only with a wooden float and

should not be trowelled smooth. Before layingthe structural concrete, the surface of the screedshould be wetted with cement slurry.4.4.6 After the side walls are constructed and

~ l l ? w e d to undergo the specified curing, theInSIde surface of the walls and the flooring shouldbe made rough with a hackino- tool washedclean with water and wire b r ~ s h e d 'so as toremove all the loose material, an d a waterproofcement plaster 1 : 3 mix with suitable proportionof an i n t . e g r a ~ waterproofing compound shouldbe appht'd In two coats, the first coat being12 mm thick and the next 10 n1m thick. Thesecond coat should be applied after allowing atime interval of at least 24 h for the first coatto harden.

4.4.7 The outside surface of the side walls~ h o u l ? ?e treated with. a waterproof renderingIn a 81mllar manner but ln this case, only onecoat of plaster 12 mIT ! thick may be appliedinstead of two successive coats.

4.4.8 The rendering should be cured as carefully as the main concrete structure. After theoutside coat of plaster has been fully cured andallowed to dry for some time, it may be givena coat of hot bitumen of the incustrial grade85/25 conforming to IS : 702-1961! as a furtherprecaution against the seepage of ground waterinto the tank.5. WORKMANSHIP5.1 General and Necessary Features ofWorkmanship - Fo r obtaining imperviousconcrete, it is not only necessary to use properlygraded aggregate and to employ a suitablydesigned mix but it is also of utmost importanceto see that the concrete is compacted by meansof suitable tools. In Case of walls Or inaccessibleportion of the forms, where use of internal vibrato r is impracticahle, the form should be hammered slowly facilitating proper placement ofconcrete. The concrete shall be thorollo-hly workedaround the reinforcement, along the 0 embed dedfixtures and into corners of forms.

*Specification for bitumen mastic for t anking anddamp-prooting (first revision ).tCode of practice for in-situ waterproofing and dampproofing treatment with glass fibre reinforced bitumen.tSpecifica tion for industrial bilumen ( T(t' i ).

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5.2 lat.ernal Vibrators - These should inva .riably be used, wherever possible. Vibratorsshould not be used for displacing concrete. Overloading the vibrators by placing too much concrete per vibrator is no t good. Over vibratingby using too many vibrators relative to quantityof concrete also is not good. Segregation by ex"cessive vibration or excessive water contentshould be strictly a voiCled. Vibrator shall bewithdrawn gradually and smoothly, and in amanner which shall no t cause suction, voids orair entrapment.5.] Construct ion and Expansion Joints -Joints in concrete structures constitute the possi-,bl e sources of leakage. Careful attention shouldtherefore, be paid to the design, location andconstruction of joints in water retaining structures made of concrete [for details) see 8 ofIS : 3370 (Part 1)-1965*15.4 Construction Joints - As far as possible,vertical joints should be avoided. This can bedone by completing a layer of concrete not morethan 60 cm high in a continuous operation working around the circumference in both directionsfrom th e starting point and repeating the process for the day's operation. Before closing day'soperation, a rebate should be formed in theconcrete on the to p surface of the wall forming'key' to ge t construction joints as explainedin 2.1.2 for flext day's operation.5.5 Before next operation is started, al l timberspoils, laitance, scum or loose concrete shall beremoved by hacking the surface and then s c r u b ~bing off with a wire brush to remove all loosemortar or aggregates. Thereafter, before resum .in g concreting operation, the surface should bethoroughly washed and wetted with water, andthen a thin coat of cement sand grout of cementmix as that in c.oncrete should be applied. Asan additional precautions, water bars as mentioned in 8 of IS : 3370 ( Part 1 )-1965* may beused at such joints. But sufficient care shall betaken when such water barriers are used, asotherwise, while pouring concrete from height,these strips may get bent and thereby restrictthe passage of concrete, causing large size poresan d honeycomb concrete. If it is no t possibleto take adequate care, it is better no t to use thewater bar. Concreting with proper measuresat joints will itself be sufficient guarantee forwater-tightness an d the use of water ba r willthen be not necessary.5.6 Expansion Joints - In concrete swimm"ingpools and reservoirs of small and medium capacities, i t is not economical to provide expansionjoints an d it is no t a practice also. In largereservoirs, expansion joints shall be provided atpredetermined positions limiting their spacingto not more than 35 m in the case of underground structures or those \vith fully covered

*Code of practice for concrete structures for the storageof i f J . u i d ~ : Part 1 General requirements..5

IS I 6494 1981sides, and no t more than 28 m in the case ofpartly exposed structures. The expansion jointsmay be constructed according -to IS : 3370(Part 1 )-1965*. Sufficient care an d precautionsshould be taken in providing them, if no t properly done, this is a source of continuous trouble.In large reservoirs, concrete cover slab s h ~ l l bedesigned to slide over the top of walls. The walltops in these cases should be suitably finishedsmooth and a layer of bitumen felt or papershould be applied.5.7 Treatment a t Fixtures Like Pipes aDdConduits - The pipes and special fixturesshould be fixed in position before concretingoperation so that these are built in at the rimeof construction. These specials should be provided with puddle collars for proper grip withconcrete and also to act as a water bar aroundthe periphery of such fixtures.5.8 In the case of underground water reservoirsand swimming pools, being founded On piles,th e damp-proofingJwaterproofiing treatment shallbe provided to bottom raft using bitumen Celtconforming to IS: 1322-1982t or IS : 7193-1974+should be provided as shown in Fig. 2. Thebitumen felt shall be laid in accordance with thedetails given in IS: 1609-J976 or IS: 9918-198111as the case may be.

PROTECTIVE BRICK WALL

WATER-PROOFING TREATMENTPILE CAP

PILESFIG. 2 A TYPICAL SKETCH OF DAMP-PaOOFINol

WATERPROOFING TREATMENT FOR UNDERGROUNDWATBR RBSERVOIRS AND SWIMMING POOLS BEING

FOUNDED ON PILES

*Code of practice for concrete structures for the storageof liquids: Part 1 General requirements.tSpecification for bitumen felts for waterpmofingan d damp-proofing ( third revision ).tSpecitlcation for glass fibre l)ase coal tar pitch an db i t u m ~ n felt.Code of practice for 1aying damp-proof treatmentusing bitumen felts ( second rtvision ).iiCode of practice for in-situ waterproofing and dampproofing treatment with glass fibre tissue reinforced bitumen

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IS : 6494 19886. TESTING AFTER CONSTRUCTION6.1 It is det-rimental to keep th e water retainingstructures dry for a longer period than 4 weeks,as it may lead to formation of cracks. So it isimperative that before the last casting is completed, water arrangement for testing the tanky,$ ready at site. Immediately after the removalof form work, the tank should be tested. All preliminaries should be completed in advance.6.2 Water should be supplied to the reservoirslo",ly at -the rate -of 300 to 450 mm depth of

r e s ~ r v o i r per day and the result closely observed,both from the angle of structural stability whetherany crack is being noticed anyw here in the structore at any time and f(om the point of view ofwatel tightness At the en d of the operation, thatis. when full supply level is reached, all valvesshall be closed tightly. The water level in thereservoir shOUld be properly marked on the wall.Leakdge through the valves should have b e ~ nchecked an d there should not be any drop dueto the same. After 24,48 and 72 h, the levelsshould be checked an d the drops in level will bea measure of water-tightness.6.3 The permissible standard usually adopted isb mm drop in 24 h in case of covered reservoiran d 11. mIl l in case of open reservoirs. Necessary adjmtment should be made depending onthe relattve humidily and other local conditions.6.4: I f there is no drop, bu t dampness is observedin the OUler su lface, such dampness may vanishin course of time as the free lime ejected out ofcement will be plugging the minor pores causingsuch dampness. If the intensity of leakage issltghtly more, then lime ma y be added to the

~ r e s L i n g water.6.5 In case of leakages, the points should bemarked an d separately treated after dewatering.6.6 I t is sometimes difficult to locate the sourceof leakages in case of underground reservoirs.I f it is from the floor, it is hardly possible tolocate unless clear cracks ar e noticed and hencecomplete floor wilf have to be treated. So in;;;uch case of underground reservoir, the drop inlevel should be recorded for every 300 mm afterkeeping the water for 24 h. I f at some stage,there is no drop, then it is presumed that flooris in order and lhe wall above that height is onlyi'esponsible for leakage. I f drops ar e noticedall through, it may be only the floor which isresponsible for the leakage or both floor an d thewall. With the presum ption that the floor isno t in order and the wall is in order, the floormay be set right leaving the treatment of thewall for the future, if necessary.6.7 For all these uncertainti es, it is recommended that some additional aids or precautions betaken for underground reservoirs, especially toprevent outside s u b s o ~ l .water to find it s wayinside when the reservOIr IS empty.

6

7. REMEDIAL TREATMENT7.1 The nature of the remedial treatment willdepend on the extent and magnitude of theleakage noticed. In the case of minor seepagetaking place through unnoticeable hair cracks,etc, the treatment mentioned under 7.1.1 to 7.1.3and 7.1.5 is recommended whereas in thecase of severe leakage or seepage throughcracks, etc, the treatment mentioned in 7.1.4 isrecommended.

7.1.1 In case of leakage through the openingof the horizontal conSlruction joint, after emptying the reserv_oirs, the leaky joint should be properly cut-off preferably by using a power-drivencarborundum saw or any other tool so as to geta square or slightly undercut groove. The jointis then filled up with cement mortar or syntheticresin after coated with mastic or bitumen.7.1.2 Coating with Sodium Silicate - Thesolution made of one part of sodium silicate

commercial ( sp. gravity l 'S kg j litre; paste varietyof purity containing sodium oxide and silica inthe ratio of 1 : 2'6 to 1 : 2'8) and three parts ofwater by volume is applied copiously with as_oftbroom over the entire surface. The treatmentconsists of three coats applied at an interval of24 h between each coat.7.1.3 For tank subjected to considerable pressure, bilumen coatings ar e commonly giv-en.Bitumen conforming to IS : 1580-1969 shouldbe applied to a perfectly dry and clean surfacein two coats each 10 mm Ihick. This is particularly suitable where there is any probabilityof the concrete cracking due to -adoption of high

working stresses in the design, lack of provisionfor settlement, contraction, etc.7.1.4 Chemical Injection - In the case of severeleakage through cracks or seepage of waterfrom surrounding ground in water logged areas,this method as indicated in 7.1.4 . 1 to 7.1.4.5may be carried out. The main advantage of

t h i ~ method IS that this treatment may be appliedat any stage, that is, even if leakage or the seepage problem develops long after the construction. In this case, the removal of the back-fillof earth around the task may be avoided as thetreatment lTlay be given from the inside surface.7.1.4.1 Holes about 50 mm dia and 25 to40 mm deep ihall be chiselled in grid patternat a spacing not exceeding 15 metre centre-tocentre all over the base, walls and top slab. Inaddition, an the construction joints shaH beopened by making a groove as to reach thereinforcement.7.1.4.2 ?vIS grouting nozzles of 25 mm di ashall then be fixed in these holes an d grooves

( s( t Fig. 3 ).Specific

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AGGREGATE

25 MS NOZZLE

FLOOR SLA9

3A FloOr and Wall

PLASTER (1 :3 )

FLOOR SLAB

3B JunctionFIG. 3 A TYPICAL SKETCH FOR FIXING OF

NOZZLB

7

IS : 6494 - 19887.1.4.3 After th e nozzles are fully set, neatcement slurry admixed with waler soluble mono-mer based chemical shaH be injected throughth e network of nozzles with -low pressure groutpumps at a pressure no t exceeding th e designed

strength of the concrete. The grouting shall bestarted at very low pressure and increased -gradually to a required pressure. The groutingshall continue till the hole refuses to take anyfurther grout, even at an increased pressure.7.1.4.4 The water soluble monomer basedchemical used shall conform generally toIS : 2645 . 1975*. In addition, it should conformto the following requirements:

a) It should be soluble in water;b) The resultant grout solution shOUld no thave viscosity greater than 1'2 centipoises;c) With addition of catalysts, gelation shouldoccur by polymerisation cross linkingchain reaction, that is, the water shall bebound into the gel structure and theresha1l not be any shrinkage of gel after-wards; andd) The gelatin be such that it ca n be con-trolIed to required time.7.1.4.5 The nozzles shall be removed

24 hours after the grouting is over and the holesshaH be finished -off neatly.7.1.5 Guniting - In th e case of leakagesfrom very many points, guniting has to -be resorted to for covering the entire surface with sufficient. thickness of mortar strengthened with mesh

reinforcement.*Specification for integral cement waterproofing com-pound ( reMsiDn ).

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Bureau of Indian StandardsBIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and qua-lity certification of goods andattending to connected matters in the country.CopyrightBIS -has the copyright of all its pubJic.'ltions. No part of these publications may be reproduced in any formwithout the prior pennission in writing of BIS. This does not preclude the free use, in the course ofimplementing the Si.'lndard, of necessary det?ils, such as symbols and sizes, type or grade designations.Enquiries relating to copyright be addressed to the Director (Publication), BIS.Review of Indian StandardsAmendments are issued to standards as the need arises on the basis of comment">. SL:1ndards are also reviewedperiodically; a standard along with amendments is reaffirmed when such review indicates that no changes areneeded; if the review indicates that changes are needed, it is k1ken up for revision. Users of Indian S ~ 1 n d a r d sshould ascertain that they are in possession of the latest amendments or edition by referring to the latest issueo('BIS Handbook' and 'Standar ds Monthly Additions'.

Amendments Issued Since PuhlicatifmAmend No. Date of Issue

BUREAU OF INDIAN STANDARDSHeadquarters:Manak Bhavan, 9 Bahadur Shah Zafar Marg, Ne w Delhi 110002Telephones: 32301 31, 323 33 75, 323 9402Regional Offices:Central Manak Bhavan, 9 Bahadur Shah Z1far Marg

NE W DELHI 110002Eastern 1/14 C.LT. Scheme VII M, V.I.P. Road, Maniktola

CALCUITA 700054Northern SeQ 335-336, Sector 34-A, CHANDIGARH 160022Southern C.I.T. Campus,]V Cross Road, CHENNAI 600113

Western Manakalaya, E9 MIDC, Marol, Andheri (East)MUMBAI 400093

Branches AHMADABAD. BANGALORE. BHOPAL. BHUBANESHWAR.COIMBATORE. FARIDABAD. GHAZIABAD. GUWAHATI.HYDERABAD. lAIPUR. KANPUR. LUCKNQW. NAGPlJR.PATNA. PUNE. THIRUVANANTHAPURAM.

Text Affected

Telegrams: Manaksanstha(Common to all offices)

Telephone32376 17, 323 3X 41

{ 33784 99, 337 K5 () 133786 26, 337 9] 20{ 60 38 43602025

{ 23502 16,235044223515 19,23523 15{ 832 92 95,832 7858832 78 91, 832 78 92

Printe_d l1y Reprography Unit. J3JS. New Ddhi