इंटरनेट मानक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru “The Right to Information, The Right to Live” “Step Out From the Old to the New” IS 13645 (1993): Guniting the Upstream Face of Masonry Dams - Guidelines [WRD 9: Dams and Spillways] “!ान $ एक न’ भारत का +नम-ण” Satyanarayan Gangaram Pitroda ““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee”” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै” Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” -IS 13845: 1993 ~~ f:q~T~ ~erT ~ "5ffu5fCf~ lf~~ CflT TR~TCf)~ur - +rT~~ff ~ Indian Standard GUNITING THE UPSTREAM FACE OF MASONRY DAMS - GUIDELINES UDC 627'82'064'3 () BIS 1993 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BA HADUR SHAH ZAFAR MARG NEW DELHI 110002 Fehruar, 1993 Price Group Z z AMENDMENT NO.1 OCTOBER 2008 TO IS 13645: 1993GUNITING THE UPSTREAM FACE OF MASONRY DAMS - GUIDELINES (Page1,clause3.1) - Substitutethefollowing fortheexisting: '3.1 Gunite - Guniteis the mortarconveyed onto a surfaceby meansof air pressure appliedthroughacontinuously feeding pressurevesseltermedas'gun'. Inthisprocess, the nominal maximum sizeof aggregate is notmorethan4.75 rom.' [Page 1,clause4.1(a)] - Substitute 'IS269 : 1989'for 'IS269 : 1982'. (Page I,clause 4.1)- Insertthefollowingsentenceattheend: 'Flyash conformingto Grade I of IS 3812 : 1981 or Calcinedclay pozzolana conforming to IS 1344 : 1981 may be used as part replacement of Ordinary Portlandcement.' (Page1,clause 4.3) - Substitute 'IS456 :2000'for 'IS456 : 1978'. (Page I, clause 4.4)- Substitute 'IS9103:1999'for 'IS9103:1979'. (Page I, clause4.S)- Substitutethefollowingfortheexisting: '4.5 Wiremesh - Welded wire fabric used shall conform to IS 1566 : 1982. ForGunite morethan25mmthick,useofwiremeshmaybepreferred.' (Page 1,clauses 4.1, 4.2, 4.3, and4.4) - Substitute the word 'shall' for 'should' whereverappears. ' (Page 2, clause6.1) - Substitute 'IS456 :2000'for 'IS456: 1978'. (Page 2, clause 7.1, line 2) - Substitute 'cementitious material' for 'cement'. (Page 2, clause 7.2.1,line 3)- Substitute'the sand-cementitious material mixture'for 'the sand-cementmixture'. AmendNo.1 toIS13645:1993 (Page 3, clauses 13 and 14) - Substitute 'shall' for 'should' wherever appears. (Page 4,AnnexA)- Substitute 'IS 456 :2000'for IS456 : 1978' and 'IS 9103 : 1999' with 'IS 9103 : 1979'. (WRD9) ReprosraphyUnit,DIS,NewDelhi,India 2 Dams (Overflow andNon-overflow) Sectional Committee, RVD 9 FOREWORD This Indian Standard wasadopted by the Bureau of Indian Standards, after the draft finalized by the Dams (Overflow and Non-overflow) Sectional Committee had beenapproved bythe River Valley DivisionCouncil. Due to seepageproblemthrough upstream faceof masonry dams on accountof poor workmanship, non-availability of skilled workers, etc, it has been feltof late to take certain additional measures to minimise this seepage and bring it down within permissible limits. The possible measures generally taken to minimise suchseepage are:(I) upstreamconcretemantle, (2) sandwitchconcrete membrane,and (3) guniting upstream face. This standard covers onlytheguidelines forguniting upstreamfaceofmasonrydams to givenecessary guidancein this respect. IS 13645: 1993 lndian Standard GUNITING THE UPSTREAM FACE OF MASONRY DAMS - GUIDELINES 1 SCOPE 4.3 Water This standard covers the general guidelines to be Water used for gunning should conform to the followed for guniting upstream face ofmasonry requirements specifiedin IS 456 : 1978. darns. 4.4 Admixtures 1 REFERENCE The Indian Standards listed in Annex A are Admixtures should be used only when so necessary adjuncts to this standard. required. Admixtures when used should meet the requirements of IS9103 : 1979. 3 TERMINOLOGY Admixtures containing chlorides should not be 3.0 For the purpose of this standard, the used in gunite exposed to water containing following definition shall apply. sulphates or in gunite which is in contact with reinforcement. 3.1 Gunite Air..entraining admixtures should not be used Gunite isthe mortar or concrete conveyed on to unless they have additional waterproofing a surface by rneans of air pressure applied properties. through a continuously feeding pressure vessel Soluble admixtures should be dissolved in water termed as 'gun'. In this process, the maximum before being added to the mix. Insoluble admix size of aggregate is restricted to lessthan 10mm. tures should be mixed with cement before mixing cement with fineaggregate. 4 MATERIALS 4.5 Wiremesh 4.1 Cement The cement used should be any of the following, Welded wire fabric used should conform to depending upon site conditions: IS 1566: 1982. For gunite more than 25 mm thickness, it would be preferable to use wiremesh. a) Ordinary Portland cement conforming to IS 269: 1982, JS 8112: 1989 or IS 5 SURFACE PREPARATION 12269 : 1987; b) Portland pozzolana cement conforming to 5.1 The masonry surface where guruting is IS 1489(Parts 1and 2) : 1991; required to be done, should be made rough by c) Portland slag cement conforming to chipping and raking out mortar joints. Chipping IS 455 : 1989; should be done by using chisels and hammers, d) Supersulphated cement conforming to After roughening the surface and raking of IS 6909 : 1990; joints, the face should be cleaned and washed by air and water jets under pressure. It should be e) Rapid hardening Portland cement ascertained that no loose material, dirt or any conforming to IS 8041 : 1990;and other material is left on the face. f) Sulphate resisting Portland cement conforming ofIS 12330: 1988. 5.2 Beforeguniting, the masonry face should be kept clean and free from oil, dirt, etc, as this 4.1 Sand would prevent the gunite from forming bond with the surface. Sand for guniting should comply with the require ments given in [S 383: 1970. Sand generally 5.3 Arrangements should be made for protecting conforming to zone 2 or 3 grading should be specified but coarser sand mayalso be used, The adjacent surfaces which are not to be gunited, by using waterproof paper. actual grading should bedecided at the site after making trial mixes. Finer sand would generally 5.4 Adjoining face or bed which will be spoiled result in greater drying shrinkage and coarser by guniting due to rebound, should also be sand would give more rebound. protected, for example, intake struture, spillway Sand should not contain more than 2 percent pier, etc. dust below 0'2 tum as the dust tends to form a harmful coating on the aggregate particles. 5.5 Absorption of water from the gunite to the Moisture content of sand should not begreate r underlying masonry is critical as this might result than 5 percent, otherwise clogging of the hose in cracking of the gunite, The surface to be and nozzle may occur. gunited should be properly dampened. IS 13645: 1993 6 l"'IXING OF WIREMESII 7.3.2 Shooting strips should be used to ensure proper thickness of gunite and to facilitate the 6.1 The wiremesh should befixedto the masonry forming ofstraight lines and sharp arrises, by means of wall plugs and nailsplaced about 750 mmapart. Adjacent sheets should be firmly 7.3.3 The nozzle should be held in the optimum tied together with wire at intervals not exceeding position for placement at all times. The nozzle 200 mm, The rnesh should be placed slightly should be held at a distance of0'6 to 1·2 m from away from the masonry ( 12111mminimum )and the receiving surface and at right angles to it. should have minimum cover according to IS456 : 1978, The minimum wiremesh spacing 7.3.4 Allverticalsurfaces should be worked from should be 50 minx 50 mm and wiremesh should the bottorn to the top. be lapped one and a half squares in all directions. 7.3.5 All sand pockets should be cut out and 7 GUNITING madegood during the course of guniting. 7.1 General 7.3.6 The first coat should be screeded with a sharp-edged trowel to bring the surface true to lineand level. Subsequent coats should be shot The gunite 1l11X should normally consist of I part onto a hardened wetted surface, of cement to 3 parts of dry sand by mass and conforming to the requirements given in 14. On vertical surface a thickness of 25 to 38 11101 may 7.3.7 With the last mix ofthe day, the work is to be tapered off to a fineedge. This edge is to normally be deposited in one operation; but, if be wetted and cleaned with an air/water jet the weather is wet, this may have to be reduced before beingjoined to the next day's work. to 19film. For higher thickness, the gunite should be built up by successiveapplications, the 7.3.8 Badly deteriorated areas should be cut back previous layer being allowed to set but not to sound rnaterial and reinforced with light mesh become hard before the application of subsequent fixed into the sound surface. layer. When successivelayers are applied, they should beof the same mix proportions, 7.3.9 Corners, re-entrant surfaces and pockets should be filled first before guniting the surface. 7.2 Mixing 7.3.10 Next layer of guniting should be allowed 7.2.1 The equipment used for gumting should after the first layer is set. From this layer all conform to IS6433 : 1972and should be capable loose materials, rebound, etc, should be removed ofdischarging the sand-cement mixture into the by broorning, sand blasting or water jetting, delivery hose under close control and it should Before the next layer is started, the surface should deliver a continuous smooth stream of uniformly be thoroughly sounded by a hammer for hollow mixed materials at the proper velocity to the areas resulting from rebound pockets or lack of nozzle. 'Thedischarge nozzleshould be equipped bond. Such areas should be cut out and replaced with a manually operated water injection system with the next layer. for directing an even distribution of water through the sand-cement mixture, The water 7.3.11 The finalcoat, generally 3to 6 tum thick, valve should be capable of ready adjustment to should be applied to the fresh, finished, screeded, vary the quantity of water and should be lightly wetted surface of the gunite. The final convenient to the nozzle man. coat should be a natrual nozzle finish. 7.1.1 The operating air pressure at the gun outlet 7.3.12 The finishedgunite should be completely should not be less than O'24N/tumJ Thewater • protected from wind, draught, rain, sunlight and pressure should be maintained uniform and be frost by suitable means. sufficient to ensure adequate hydration at all times. Hydration is considered to be adequate 8 AIR SUPPLY when the gunite exhibits a silky and glistening wet surface as it is placed. The water pressure Properly operating air compressor of ample should exceed the operating air pressure at the capacity is essential for satisfactory operation. nozzle by at least 0·1 N/mm2 so as to ensure The compressor should becapable of maintaining that the water is intimately mixed with other a supply of clean and dry air adequate for materials. At the nozzle the water pressure is maintaining sufficientnozzle velocity for all parts generally not lessthan O'4 Njmm'', of work. Air hoses should be capable of with standing at least twice the operating pressure. 7.1.3 In case ofwetsand, the moisture content is to be accounted for while designing the gunite 9 WATER SUPPLY lllix. Water is supplied to the valve titted to the nozzle 7.3 Guniting Operation through a light, flexible, high pressure line. Wherever possible, thialine should be connected 7.3.1 Before starting the guniting operation, the directly to the main supply provided that this surface should be prepared asdescribed in 5. supply has pressure ofnot lessthan 0'4 Njmm", 2 IS 13645: 1993 10 REBOUND them for tests. The thickness should bethe same as in the structure except that it should normally Materials which rebound and drop down, should be not lessthan 7'5 em. The panels arc fabri in no ease bereused and should be immediately cated bygunning on to a back form of plywood. removed and disposed off. The guniting should Aseparate panel should be fabricated for each bedone in such a manner that waste of cement mix design being considered, and also for each due to rebound is minimum. gunning position to be encountered in the structure. 11 SUSPENSION OF WORK 11.1 Guniting operation should be suspended in 14.1.3 Testcores should, however, be taken from condition of likely exposure to high winds, the structure as often as necessaryto ensure that freezingor rain. the control tests reflect the quality of material in the structure bycorrelating to the results from 11.1 At the end of each day's work or on the tests made from panels (see14.1.2 ). stopping of work for any other reason, the gunited surface should besloped to a thin edge 14.1.4 The cores for testing should have a and the work should be resumed after cleaning minimum diameter of 70S enl and a length the surface (see 7.3.7 ). diameter ratio of at least 1. The test should be done according to IS 516 : 1959. 12 FINISliING 14.2 PermeabilityTest Natural gun finish is preferred. No further finishing should becarried out. 14.2.1 When tested according to the method 13 CURING described in 14.2.2, 50 mm thick gunite specimens should show nowaterpercolation upto O'7N/n11n2 The finished gunite should be cured by con pressure. tinuous and uniform water sprays after a period of 8h from placement and for a period of 7days. 14.2.2 The permeability test should be carried The curing water should be of the same quality out on gunite specimens of IO~ mm dia and as that of the mixingwater. 50 mm high using the equipment and the pro cedure specified in IS 1727: 1967, with the 14 TES1' REQUIREMENTS followingmodifications: 14.1 Compressive Strength a) Permeability test should be carried out usinga final water pressure of O'7N/nlln~0 14.1.1 The test should be carried out on gunite specimensat the age of 7 days or 28days or both b) The gunite samples should he drilled out and value should conform to the specific require fr0J11 the upstream face of the masonry rnents of the structures, The average value of dam of preferable extracted from the three specimensshould beconsidered. gunited test panels, at least 30 em square and 75 111111 thick, cast during guniting 14.1.1 It isgenerally not feasible or desirable to operation. core the structure to obtain specimensfor regular c) The test should be.conducted on 28-day control tests. Therefore, small unreinforced test old specimens, panels, at least of30em square, so as to be large enough to obtain all the test specimens needed d) For each test, three specimens should be and also to indicate what quality and uniformity tested at a time and the average for three may be expected in the structure, should be samples should be reported as the per periodically gunned, and cores extracted from meability of the gunite, 3