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IS 4926: Code of Practice Ready-Mixed Concrete PDF

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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 4926 (2003): Code of Practice Ready-Mixed Concrete [CED 2: Cement and Concrete] “!ा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 4926:2003 Indian Standard READY-MIXED CONCRETE — CODE OF PRACTICE (Second Revision) Ics 91.100.30 0 BIS2003 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI I1OOO2 May 2003 Price Group 8 Cement and Concrete Sectional Committee, CED 2 FOREWORD This Indian Standard (Second Revision) was adopted bythe Bureau of Indian Standards, after the draft finalized bytheCement and Concrete Sectional Committee had beenapproved bytheCivil Engineering Division Council. This standard was first published in 1968. The firstrevision ofthestandard wasbrought out in 1976. Inthe first revision themajor modifications included increase inthetime limitfor supply ofready-mixed concrete byhalf an hour inorder to make the standard more practicable and permitting useof fly ash. This second revision isbeing brought out to incorporate modifications found necessary based on the experience gained withthe useofthisstandard andspecially inthecontext ofrecentdevelopments inthis field inthe couch-y. The significant modifications included are asfollows : a) Rationalization of definitions and addition ofdefinitions for more terms. b) Requirements for materials brought in line with IS 456:2000 ‘Plain and reinforced concrete—Code of practice’. c) Minimum testing frequencies introduced for aggregates and water. d) Basis of supply modified to bring it in line with IS 456:2000 ‘Plain and reinforced concrete—Code of practice’. e) Transportation time made uniform to2h. t) Requirement oftemperature ofconcrete deleted. g) Sampling procedure hasbeen modified. h) Tolerance limits forworkability have been modified. j) Aclause on non-compliance hasbeen included. k) A detailed clause on production and delivery including plant safety and maintenance and environmental considerations has been included. m) Adetai!ed clause on quality control has been included. n) Adetailed clause on order processing andtraining has been included. p) Detailed provisions on calibrat ion andweighing equipment accuracy hasbeen introduced asAnnex E. Foreffective implementation ofthe provisions ofthestandard, itmaybe desirable thatthe ready-mixed concrete plantsoperate their system under athird partycertification schemetoensure operation ofawell structured system and to build confidence inthe users of suchconcrete. The composition ofthe Committee responsible for formulation ofthis standard isgiven atAnnex H. For the purpose of deciding whether a particular requirement of this standard iscomplied with the final value, observed orcalculated, expressing theresult ofatestshallberounded offinaccordance with IS2:1960 ‘Rules for rounding off numerical values (revise@’. The number of significant places retained in the rounded off value should bethe same asthat ofthe specified value inthis standard. IS 4926:2003 Indian Standard READY-MIXED CONCRETE — CODE OF PRACTICE (Second Revision) 1SCOPE the aggregate in a saturated surface dry condition) to the mass of cement including mineral additives as This standard covers the requirements for the per 4.3 inaconcrete mix. production andsupplyofready-mixed concrete.Itdoes notcovertheplacing,compaction, curingorprotection 3.8 Grade of Concrete—Numerical value of of concrete after delivery. characteristic compressive strength of 150mmcube of concrete at 28 days, designated by ‘M’ followed by 2REFERENCES thisstrengthvalueinN/mm*characteristic compressive strength. The standards given in Annex A contain provisions which through reference in this text, constitute 3.9Minimum Cement Content —The minimum mass provisions ofthisstandard. Atthetime ofpublication, of cement including mineral additives as per 4.3 the editions indicated were valid. A1lstandards are required bythepurchaser tobepresent, inunit volume subjecttorevision, andparties toagreements basedon of specified mix (see also Note 2 under Table 5 of IS this standard are encouraged to investigate the 456). possibility of applying the most recent editions of the standards indicated inAnnex A. 3.10 Prescribed Mix—Mix for which the purchaser specifies the proportions of the constituents and is 3TERMINOLOGY responsible for ensuring that these proportions will produce aconcrete with the performance required. 3.0 For the purpose of this standard, the following definitions shall apply. 3.11 Producer— Person or authority entering a contract to supply ready-mixed concrete. 3.1 Agitator —Truck mounted equipment designed to agitate concrete during transportation to the siteof 3.12 Purchaser—Person or authority entering a delivery. contract to buy ready-mixed concrete. 3.2 Batch —Quantity of concrete mixed inone cycle 3.13 Ready-Mixed Concrete— Concrete mixed in a of operations of a batch mixer or the quantity of stationary mixer inacentral batching andmixing plant concrete conveyed ready-mixed in a vehicle or the or inatruck-mixer and supplied inthe fresh condition quantity discharged during 1min from a continuous tothepurchaser eitheratthesiteorintothepurchaser’s mixer. vehicles. 3.3Characteristic Strength —The value ofstrength 3.14Truck-Mixer —A mixer generally mounted ona ofconcrete below which notmore than 5 percent of self-propelledchassis,capableofmixingtheingredients the population of all possible strength measurements ofconcrete andofagitating the mixed concrete during ofthe specified concrete are expected to fall. transp.ortation. 3.4 Concrete —A mixture of aggregate, cement and 4MATERIALS water with orwithout admixtures and/or additions and including entrapped or entrained air, for all uses but 4.1 Selection and Approval of Materials excluding allmortars otherthanforuseasfloororroof Materials used should satisfy the requirements for the screeds. safety, structural performance, durability and 3.5 Density of Fresh Concrete—Mass of aquantity appearanceofthefinished structure, takingfill account of compacted fresh concrete divided by its volume, of the environment to which itwill be subjected. The expressed inkg/m3 inaccordance with IS 1199. selection and use of materials shall be in accordance with IS 456. Materials used shall conform to the 3.6 Designed Mix—Mix for which the purchaser is relevant Indian Standards applicable. Wherematerials responsibleforspeci~ing therequiredperformance and areusedwhich arenotcovered bytheprovisions ofthe the producer is responsible for selecting the mix relevant Indian Standard, there should be satisfactory proportions to produce the required performance. dataontheirsuitabilityandassuranceofqualitycontrol. Records and details of performance of such materials 3.7 Free Water-Cement Ratio —Ratio of the mass should be maintained. Account should be taken of of free water (that isexcluding the water absorbed by possible interactions and compatibility between 1 IS 4926:2003 materials used. Also,prior permission ofthepurchaser of concrete shall be regulated by controlling its shall reobtained before useofsuch materials. workability orbymeasuring andadjustingthemoisture contents of its constituent materials. The producer’s 4.2 Cement—Cement used for concrete shall be in production staffandtruck-mixer drivers shallbemade accordance with the requirements of IS456. aware of the appropriate responses to variations in concrete consistence of a particular mix caused by 4.3Mineral Admixtures —Useofmineral admixtures normal variations in aggregate moisture content or shall bepermitted inaccordance withtheprovisions of grading. Is 456. 5GENERAL REQUIREMENTS 4.4 Aggregates —Aggregates used for concrete shall be in accordance with the requirements of 1S456. 5.1 Basisof Supply Unless otherwise agreed testing frequencies for aggregates shall beasgiven inAnnex B. 5.1.1 Ready-mixed concrete shall be supplied having the quality and inthe quantity inaccordance with the 4.5 Chemical Admixtures requirements agreed with the purchaser or h$sagent. Notwithstanding this, the concrete supplidd shall 4.5.1 Useofchemical admixtures shallbepermitted in generally comply with therequirements of 1S456. accordance with the provisions of IS456. 5.1.2Allconcretewillbesuppliedandinvoicedinterms 4.5.2 It shall be the responsibility of the producer to of cubic metres (full or part) of compacted fresh establish compatibility andsuitability ofanyadmixture concrete. Allproportioning istobecarriedoutbymass with the other ingredients ofthe mix andto determine except water and admixture, whichmay be measured the dosage required to give the desired effect. by volume. 4.5.3 Admixtures should be stored in a manner that 5.2Transport ofConcrete prevents degradation of the product and consumed within the time period indicated by the admixture 5.2.1General supplier. Any vessel containing an admixture in the 5.2.1.1 Ready-mixed concrete shall be transported plant or taken to site by the producer shall be clearly from the mixer to the point of placing as rapidly as marked asto its content. practicable bymethods thatwillmaintain the required 4.5.4 Whenoffering ordelivering amixtoapurchaser workability and will prevent segregation, loss of any it should be indicated if such a mix contains an constituents or ingressofforeign matter orwater. The admixture or combination of admixtures or not. The concrete shall be placed as soon as possible after admixtures may be identified generically and should delivery, asclose asispracticable to itsfinal position bedeclared on the delivery ticket. toavoidrehandlingormovingtheconcretehorizontally byvibration. Ifrequired bythepurchaser the producer 4.5.5 The amount ofadmixture addedto amix shallbe can utilize admixtures to slow down the rate of recorded in the production record. In special workability10SSh,oweverthisdoesnotremovetheneed circumstances, if necessary, addition al dose of for the purchaser to place the concrete as rapidly as admixture may be added at project site to regain the possible. The purchaser should plan his arrangements workability of concrete with the mutual agreement soastoenable afull loadofconcrete tobe discharged between the producer and the purchaser. within 30min ofarrival on site. 4.6 Water 5.2.1.2 Concrete shall betransported inatruck-mixer unlessthepurchaser agrees tothe use ofnon-agitating 4.6.1 Water used shall be in accordance with the vehicles. When non-agitating vehicles are used, the requirements of IS456. Unless otherwise agreed, the mixed concrete shallbe protected from gain or lossof testing frequencies for water shall be as given in water. Annex B. 5.2.2 Time in Transport 4.6.2 The useof re-cycled water isencouraged aslong asconcreteofsatisfactoryperformance canbeproduced 5.2.2.1 The general requirement isthat concrete shall andstepsaretaken tomonitor thebuildup ofchlorides be discharged from the truck-mixer within 2 h of the in any recirculated water and that any subsequent time Gfloading. However, a longer period may be adjustments to the mix design are made to ensure that permitted if retarding admixtures are used or in cool any overall limit on chloride contents issatisfied. The humid weather or when chilled concrete isproduced. addition ofany recycled water shallbe monitored and 5.2.2.2 The time of loading shallstart from adding the controlled tomeet these requirements. mixing water tothe dry mix of cement and aggregate 4.6.3 The total amount ofwater added tothe mix shall orofaddingthecementtothewetaggregatewhichever berecorded intheproduction record. Thewatercontent isapplicable. 2 IS 4926:2003 5.3Ready-mixed concreteplantshallhavetestfacilities 6.3.2 Unless otherwise agreed between the parties at its premises to carry out routine tests as per the involved, theminimum testing frequency tobeapplied requirement of the standard. bythe producer inthe absence of arecognized ready- mixed concrete industry method ofproduction control, 6 SAMPLING AND TESTING OF should beonesample forevery 50m3ofproduction or READY-MIXED CONCRETE every 50 batches, whichever isthe greater frequency. Threetestspecimens shallbemade upforeach sample 6.1 Point and Time of Sampling fortesting at28 days (see also IS456). For the assessment of compliance of ready-mixed concrete, the point and time of sampling shall be at In order to get a relatively quicker idea of the quality discharge fromtheproducer’s delivery vehicleorfrom of concrete, optional test on beams for modulus of the mixer to the site or when delivered into the rupture at72+2horat7daysorcompressive strength purchaser’s vehicle. It is critical that the sampling testat7days maybe carried out inaddition to28 days procedure andequipmentusedenablesasrepresentative compressive strength test. For this purpose the value a sample as possible to be taken of the quantity of shouldbearrived atbasedonactualtesting. Inallcases concrete delivered (seeAnnex C). 28dayscompressive strength shallalone bethecriteria for acceptance orrejection ofthe concrete. The sampling may be carried out jointly by the purchaser andthe supplier with itsfrequency mutually 6.3.3 The purchaser shall inform the producer if his agreed upon. However, itwillnotabsolve thesupplier requirements for sampling and testing are higher than ofhisresponsibility from supplying concrete asperthe one sample every 50 m3or 50 batches, whichever is the greater frequency. requirements given inthisstandardorotherwise agreed towhere sopermitted inthe standard. 6.4 Additional Compliance Criteria 6.2 Workability Anyadditional compliance criteria shallbedeclared to the producer bythepurchaser prior tosupply and shall 6.2.1 The test for acceptance isto be performed upon the producer’s delivery vehicle discharge on site or be mutually agreed upon in terms of definition, upondischargeintothepurchaser’svehicle.Ifdischarge tolerance, frequency ofassessment, method oftest and significance of result. from the producers’ vehicle is delayed on site due to lack of preparedness on behalf of the purchaser then 6.5 Non-Compliance theresponsibility passes tothe purchaser after adelay ofmore than 30 min. The action tobetaken incaseofnon-compliance shall be declared and mutually agreed upon. Theworkability shall bewithin thefollowing limitson the specified value asappropriate: 7 INFORMATION TO BE SUPPLIED BY THE PURCHASER Slump + 25 mm or + 1/3 of the specified valu e, whichever is 7.1 The purchaser shall provide to the producer the less. details of the concrete mix or mixes required by him andallpertinent information ontheuseofthe concrete Compacting factor : +0.03,wherethespecifiedvalue andthe specified requirements. Prior to supply taking is0.90 or greater, place, itisrecommended thatameeting isheldbetween * 0.04, where the specified the purchaser andthe producer. Itsobjective to clarify value islessthan 0.90 butmore operational matters, suchasnotice to begiven prior to than 0.80, and delivery, delivery rate, the name of the purchaser’s authorized representative who will coordinate +0.05,wherethespecifiedvalue deliveries,anyrequirements foradditional servicessuch is0.80 or less. aspumping, on sitetesting or training, etc. Flowtable test may bespecified for concrete, forvery 7.2 Designed Mixes high workability (see IS 9103). Acceptance criteria for spread (flow) are to be established between the Where the purchaser specifies a designed mix to be supplier and the purchaser. supplied itisessential that all relevant information is conveyed to the producer. In order to assist in this, 6.3Specified Strength the format given inAnnex Dmay becompleted and 6.3.1 Compliance shall be assessed against the forwarded tothe producer atthe time of enquiry . requirementsofIS456orotheragreedIndianStandard. 7.3 Prescribed Mixes The purchaser may perform his own sampling and testing or may enter in to an arrangement with the 7.3.1 The concrete mix shall be specified by its producer to provide his testing requirements. constituent materials and the properties or quantities 3 1S 4926:2003 of those constituents to produce a concrete with the Cement shall be stored and stacked in bags and shall required performance. The assessment of the mix be kept free from the possibility of any dampness or proportions shall form an essential part of the moisture coming in contact with them and where compliance requirements. Thepurchaser shallprovide cement can be stored and retrieved without undue the producer with all pertinent information onthe use damage tothebags. Thebags areto be protected from oftheconcrete andthespecified requirements. Inorder becoming dampeitherfromtheground orthe weather. to assist inthis, the format given inAnnex Dmay be The cement is to be used in the order it is delivered followed with suitable modifications as applicable to (seealso IS4082). prescribed mixes. Incase,thecement remains instorage formore than 3 8 INFORMATION TO BE SUPPLIED BY THE months, the cement shall be retested before use and PRODUCER shall be rejected if it fails to conform to any of the requirements given inthe relevant Indian Standard. 8.1 When requested, the producer shall provide the purchaser with the following information before any 9.1.1.2 Dry pulverized fuel ash and other mineral concrete issupplied: admixtures a) Nature and source of each constituent material, Suitableseparatearrangement forstorageofpulverized b) Source of supply of cement, and fuelash,silicafume,metakeolin, ricehuskash,ground granulated blast furnace slag suchasfor cement, shall c) Proposed proportions or quantity of each beprovided, inthe plants utilizing these materials. constituent/m3 of fresh concrete. 9.1.1.3 Aggregates (coarse andfme) 8.2 When requested, the producer shall provide the purchaser the following information on admixtures: Stockpiles shallbefreedraining andarranged to avoid a) Generic type(s) oftbe mainactiveconstituent(s) contamination and to prevent intermingling with inthe admixture; adjacentmaterial. Handlingprocedures forloading and unloading aggregates shall be such as to reduce b) Whether ornottheadmixture containschlorides segregation to a minimum. Provision shall be made and ifso, the chloride content ofthe admixture for separate storage for each nominal size and type of expressedasapercentageofchlorideionbymass aggregate and the method of loading of storage bins of admixture; shall be such as to prevent intermingling of different c) Whether or not the admixture leads to the sizesand types. Fine aggregates shall be stacked ina entrainment of air when used at the adopted placewhere lossdue totheeffect ofwind isminimum dosage; (seealso IS4082 and IS456). d) Where more than one admixture is used, 9.1.1.4 Water confirmation oftheir compatibility; and Anadequate supply shallbeprovided andwhen stored e) Initial and final setting time of concrete when ontheplant suchstorage facilities shall bedesigned to admixture isused at adopted dosa ge (tested as minimize the risks ofcontamination. per 1S8142). 9 PRODUCTION AND DELIVERY 9.1.1.5 Chemical admixtures Tanks or drums containing liquid admixtures shall be 9.1 Plant and Equipment clearly Iabelled for identification purposes and stored 9.1.1 h{ateriul.s Storage and Handling insuchawaytoavoid damage, contamination or the effectsofprolongedexposuretosunlight(ifapplicable). 9.1.1.1 Cement Agitationshallbeprovidedforliquidadmixtures,which Separate storage for different types and grades of arenot stable solutions. cement shall be provided. Containers may be usedto 9.1.2 Batching Plants and Batching Equipment store cements of different types provided these are emptied before loadinganew cement.Binsorsilosshall Hoppers for weighing cement, mineral admixtures, be weatherproof and permit free flow and efficient aggregates and water and chemical admixture (if discharge ofthecement. Eachsiloorcompartment ofa measured bymass) shallconsist of suitable containers si10shall becompletely separate andfittedwithafilter freely suspended fromascale or other suitable load- oralternative method ofdustcontrol. Eachfilterordust measuring device and equipped with a suitable control system shall be of sufficient size to allow discharging mechanism. The method ofcontrol ofthe delivery of cement to be maintained at a specified loadingmechanism shall be such that,asthequantity pressure, and shall be properly maintained to prevent required in the weighing hopper is approached, the undueemissionofcementdustandprevent interference material may be added atacontrollable rate andshut with weighing accuracy by build up of pressure. offprecisely within the weighing tolerances specified 4 IS 4926:2003 inAnnex E.Theweighing hoppers forcement, mineral from those used for other materials and on a scale of admixtures aggregateshallbecapableofreceiving their appropriate sensitivity, measurement being taken from rated load,without theweighed material coming into azeroreading. Aggregates shallbemeasured bymass, contact with the loading mechanism. Where therated allowance being made forthe free moisture content of capacity ofabatching plant mixing cycle is lessthan theaggregates. The added water shallbemeasured by 2.0 m3,additional precautions shall betaken toensure volume or by mass. Any liquid chemical admixture that the correct number of batches are loaded intothe (orpaste) shallbemeasured byvolume orbymass and truckmixer. Theweighinghoppersshallbeconstructed anysolidadmixturebymass. Whenweighingmaterials, soastodischarge efficiently and prevent the build up anybuildupinthehopper during thedaymustbetared of materials. A tare adjustment, upto 10percent of out or allowed for in the batch weights. After the nominal capacity of the weigh scale, shall be measurement allmaterials shall bedischarged intothe provided ontheweighing mechanism sothatthescale mixer without loss. can be adjusted to zero at least once each day. Dust seals shall be provided on cement hoppers between The accuracy of the measuring equipment shall be the loading mechanism and the weigh hopper, and within*2percentofthequantity ofcement andmineral shall be fitted so asto prevent the emission of cement admixtures being measured and within + 3percent of dustand notto affect weighing accuracy. The hopper the quantity of aggregate, chemical admixture and shallbeventedtopermit escapeofairwithout emission water being measured. The plant operator shall be “ of cement dust. provided with a clear display of the quantities of materials tobebatched foreachmix andbatch sizeand Vibrators or other attachments, where fitted, shall not with information identi~ing the display to beselected affect the accuracy of weighing. There shall be for eachdesigned and prescribed mix to beproduced. sufficient protection to cement and aggregate weigh Analogue scale displays for the weighing of cement, hoppers and weighing mechanisms to prevent mineral admixtures, aggregates and water shall be interference with weighing accuracy by weather readily discemable from the operating position. For conditions or external build-up ofmaterials. digital readouts the numerals shall be readily Where chemical admixture dispensers are used, they discernible from the operating position. shall becapable ofmeasurement within thetolerances Fully automatic production systems shall be fitted inAnnex E and acalibrated container orweigh scales with control equipment to allow the correct operation shallbeprovidedtochecktheaccuracyofmeasurement of the plant to be monitored during weighing and at leastonce amonth. batching. Automatic control systemsonbatching plants Whereacontinuous mixer with ribbon loading isused, shallnotcommencebatchinguntilallhoppershavebeen the batching procedure specified by the manufacturer emptied and/or tared andthe scaleszeroed unless such ofthe plant shall be followed. systems are designed to take account of build up in their programming. Each control on the batching console and weigh-dial or display shall be clearly labelled with its function All scales shall be tested and calibrated as per and where concerned with the batching of materials, Annex E. the material type. 9.1.4 Mixing When more than onetype orgrade of cement isbeing used,theweighing device anddischarge screworother 9.1.4.1 Washing out water parts of the transfer system shall be empty before changing from one type of cement to another. Before loading concrete materials or mixed concrete intoeither astationary mixer ortruck mixer any water Whenpulverized fuelashandothermineral admixtures retained inthe mixing drum for washing out purposes are batched through the cement weigh system, the shall becompletely discharged. weighing device and discharge screw orother parts of thetransfer system shall be empty when the weighing 9.1.4.2 Stationa~ or central mixers system has returned to zero reading or completed the batch. Stationary mixers shall not be loaded inexcess of the manufacturer’s rated capacity. The mixing time shall Where a backweigh system is utilized to weigh be measured from the time all the materials required materials a system shall be in place so as to prevent for the batch, including water, are in the drum of the materials being loaded duringtheprocessofweighing. mixer. The mixing time shall not be less than that recommended bythemanufacturer. Whereacontinuous 9.1.3 Measuret72ent of Materials mixing plant isusedthecomplete mixing time shallbe Cement and mineral admixmre materials shall be sufficient toensure that the concrete isofthe required measured bymass inahopperorcompartment separat e uniformity. 5

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