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(e) No change in the specified mix will be permitted except with the authority of the Engineer. 1.07.1.1 MIXING (a) (b) (c) All concrete used in the works shall be mixed in mechanical batch mixer of approved pattern fitted with power driven loading skip. Each batch of concrete shall be thoroughly mixed for period of not less than 2 minutes to produce wellmixed concrete of uniform consistency and appearance. The minimum mixing period specified is predicated on proper control of the speed of rotation of the mixer and the introduction of the materials including water into the mixer. The engineer reserves the right for the required uniformity of composition and consistency within the batch and from batch to batch. The leading skip the mixer drum its blades and the discharge chute shall be kept clean and free from hardened mortar or concrete. 1.08 CONVEYING AND PLACING Before placing concrete the sub grade should be properly prepared and the forms and reinforcement should be erected. A moist sub grade is especially important to prevent too rapid extraction of water from the concrete when pavement, floors and similar work are be cast in hot whether. Where the foundation is rock, all those materials should be removed before the concrete is placed. When it is necessary to cut rock in foundation, the surfaces in general should be vertical or horizontal and not sloping. Where formworks are used they shall be clean, tight, adequately braced and constructed with materials that will import the desired texture to the finished concrete. Care should be taken to see that sawdust nails and other debris are removed form the space to the concerted. Forms should be moistened or oiled previous to placing to facilitate free removal. Where they have been exposed to the sun it may be necessary to saturate the wood thoroughly before concreting. Reinforcing steel used for concreting should be cleaned and free of loose rust or mill scales. The concrete shall be placed before the initial set so that it remains workable and can be compacted satisfactorily. Additional water shall not be added to improve workability as it disturbs the water cement ratio. Placing of concrete shall be done in a continued operation till the predetermined position of construction joint is reached. The maximum thickness of layer shall not be mire than 300mm even for wet consistencies. Horizontal flow concrete shall be avoided as far as possible Each subsequent layer shall be deposited while the previous layer is soft In sloping member small quantities of concrete shall be deposited starting from the lower end of the slope. In case of reinforced concrete work using shutter or formworks, the shutter and forms must be rendered watertight and concrete shall not be deposited until the engineer in charge has inspected reinforcement, forms and their support. Before depositing fresh concrete over or against hardened concrete of construction joints the hardened surface shamble roughened and cleared by wire brush or water jet with a pressure of 0.07kg/cm2 or by sand blasting after the concrete has hardened sufficiently. The surface shall not be allowed to any between jetting and placing on concrete. A thin layer of motor of the same perpetration as in the concrete shall be applied just before placing fresh concrete. 1.09 VIBRATION (a) The concrete after placing shall be thoroughly compacted as it is placed to secure a dense structure close bond with reinforcement and smooth surface by robbing, hand tamping or mechanical vibration as required and directed by the engineer. Concreting between two walls shall be compacted by power driven vibrators of the immersion type and concrete in slabs with no form work or upper surface shall be compacted by power driven vibrators of the pan type or by vibrating screeds. The vibrators shall be of ample power operating at not less than 6000 RPM and of kind approved by the engineer. They shall be operated by workmen skilled in their use he shall be additional to the laborers employed for placing and tamping the concrete. 27
(b) (c) (d) (e) 1.10 CURING (a) No concerting shall begin until the required number of vibrators are available, all being tested and found to be in good working condition at the work site. In general the number of vibrators available for use shall be as follows On vibrator for each four cubic meter of concrete placed per hour and one stand by vibrator for each three vibrators in service but in any case at least two vibrators in good working order shall be present at the forms. Immersion vibrators shall be inserted and withdrawn slowly at a uniform rate of approximately 10mm per second. Compaction shall be deemed to be completed when cement mortar appears in a circle round the vibrator. The immersion vibrators shall be inserted at intervals determined by area of mortar shown after the previous vibrator with a certain allowance made for over lapping. The immersion vibrators shall not be allowed to come into contract with the formwork and the reinforcement. Pan vibrators shall be placed on the surface of the concrete, which shall have previously been tamped and leveled but left slightly high to allow for settlement during compacting until cement mortar appears under the pan. The vibrators shall then be lifted and placed on the adjoined area and the operation shall be repeated until the whole surface has been compacted. Alternatively a vibrating screed spanning the full width of the panel shall be used. In all case the placing of concrete shall be sufficiently ahead of the vibrators so that the mass of concrete beyond the vibrators is sufficient to a stand flooring while vibration is in progress. On the other hand the concrete shall be fully compacted before initial set is attained. As soon the freshly placed concrete has hardened sufficiently to withstand such treatment without damage the exposed surfaces shall be completely covered with wet gunny bags or any other means approved by the engineer and shall be kept thoroughly wet continuously by generous applications of water every two hours for period of 14 days. Water shall be allowed to run down between the forms and the formed concrete surfaces. Floor slabs shall have water impounded on them for period of at least 14 days after placing. Any excess water or cream that may have come to the surface shall first be removed dry cement or dry mixture of cement and sand shall not be sprinkled on the surface to absorb such access moisture. 1.11 FORMWORK (a) (b) (c) (I) (ii) (d) (e) All form work shall be erected true to line and level as shall be adequately secured and braced to prevent deflection or movement during the placing tamping or vibration of the concrete and shall be sufficiently tight to prevent loss of liquid from the concrete. If for any reason the form work moved after the concrete has been placed thus disturbing the freshly placed concrete or if the concrete is found to be defective in alignment, the contractor may be ordered to take out and replace such concrete without extra payment. All the faces of form work in contract with concrete shall be smooth and free form surface imperfections. The formwork shall be constructed with any of the following materials depending of suitability. Steel shuttering of 14 gauges for RCC works especially in roof/ floor slab and columns. As described in Instruction to Bidder. Waterproof plywood of approved manufacture 18mm thick securely fixed to timber may be used after approval by the engineer in charge. The height of formwork will be as follows Timber formwork should not exceed the height of 1200mm Steel formwork should not exceed the height of 2150mm The use of wire passing through the concrete for the purpose of securing form will not be permitted. Bolts may be used but their number shall be kept to the minimum required to secure the formwork rigidly. The bolts shall not be less than 13mm dia. The hole left by bolts shall be cleaned and filled with cement mortar containing waterproofing materials of approached quality. Before concreting all forms shall be cleaned and treated with approved mould oil to prevent adhesion of the concrete care being exercised to ensure that no oil falls on the set concrete or reinforcement provision shall 28
Page 1 and 2: ISO 9001 & 14001 CORPORATION ORISSA
Page 3 and 4: Orissa Industrial Infrastructure De
Page 5 and 6: CONTRACT DATA SL NO DESCRIPTION DET
Page 7 and 8: 1.9. T h e bidder intending to part
Page 9 and 10: loading his bid. He is required to
Page 11 and 12: 14.2. In exceptional circumstances,
Page 13 and 14: at the opening location if they so
Page 15 and 16: F. AWARD OF CONTRACT 26. AWARD CRIT
Page 17 and 18: SPECIAL CONDITION 1. Notwithstandin
Page 19 and 20: BIS CODE REFERENCE 1) Concrete shal
Page 21 and 22: (a) (b) (c) (d) The contractor shal
Page 23 and 24: (b) The length width and depths of
Page 25 and 26: (b) (c) (d) (e) (f) Fine aggregate
Page 27: (D) (i) (ii) (iii) (iv) The amount
Page 31 and 32: (c) Where it is necessary to mainta
Page 33 and 34: Any error in the specification or i
Page 35 and 36: NOTES :- SCHEDULE OF ITEMS 1. Detai
Page 37 and 38: Dated this ........................
Page 39 and 40: 7. All the measurement shall be joi
Page 41 and 42: SPECIAL NOTE 1. The rates to be quo
Page 43 and 44: Should this tender be accepted I/We
Page 45 and 46: EARNEST MONEY DEPOSIT Ref. No._____
Page 47 and 48: SECURITY DEPOSIT BANK GUARANTEE PRO
Page 49 and 50: PERFORMANCE GUARANTEE FORMAT PROFOR
Page 51 and 52: A G R E E M E N T The Agreement is
Page 53 and 54: GENERAL RULES AND DIRECTIONS FOR TH
Page 55 and 56: Infrastructure Development Corporat
Page 57 and 58: CONDITIONS OF CONTRACT 56
Page 59 and 60: In any case in which under any clau
Page 61 and 62: Contractor shall forthwith pay the
Page 63 and 64: NO COMPENSATION FOR ALTERATION IN O
Page 65 and 66: sustained owing to neglect of the a
Page 67 and 68: The Corporation shall be entitled t
Page 69 and 70: CLAUSE - XXXVIII: The consumption o
Page 71 and 72: i) The Contractor shall maintain a
Page 73 and 74: SPECIAL CONDITIONS OF FORMING A PAR
Page 75 and 76: 9. All centering/ shuttering and sc
Page 77 and 78: 33. Under no circumstances interest
Page 79 and 80:
SPECIAL TERMS & CONDITIONS FOR SAFE
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TENDER SCHEDULE CONSTRUCTION OF PRO
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Sl. Description of items of work Qn
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Sl. Description of items of work Qn
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BID DOCUMENT - IDCO

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