BANGLADESH POWER DEVELOPMENT BOARD TENDER ... - BPDB

deformed steel bars and shall conform to ASTM A6 15 Grade 60.(v) Joint Sealer Concrete joint bituminous sealer for all joints shall conform toASTM Dl 850-67, "Specifications for Concrete Joint Sealer, Cold-Application Type".(vi) Slab reinforcement The slab reinforcement shall be made of steel bars of10 mm conforming to ASTM A615 Grade 60. The longitudinal and transversespacing shall be 15cm respectively or as design each intersection shall be firmlybound by binding wires or fixed by an adequate method approved by the Board.It shall be embedded in the concrete at 6cm below the surface.(2) Construction Method(i)FormworkThe concrete pavement shall be constructed one lane at a time. The side formsfor the concrete pavement shall be made of shaped steel sections which shallhave sufficient strength when staked down to resist the pressure of the concretemixer and finishing machine, or finishing tools, without springing. They shall bestraight and of a depth equal to the thickness of the pavement at the edge andfree from warps or bends at all times. Flexible or curved forms of proper radiusshall be used for curves 30 metres radius or less. The form base shall not be lessthan twenty (20) centimetres wide for forms twenty (20) centimetres or more inheight. Flange braces shall extend outward on the base not less than two-thirds(2/3) of the height of the form. The use of wooden side forms may be permitted.Timber formwork shall be oiled or greased at all times to prevent warping orcracking.When placing the forms, they must be seated firmly and in contact with the subbasesurface for their entire length, exactly on the desired line and grade.Before the mixing of concrete, forms shall have already been set for a sufficientlength well in advance of the forward end point where the concrete is to beplaced, but in no case less than the length between expansion joints, except forclosures which may require a shorter length. Sufficient forms shall be provided sothat it will not be necessary to move those in place within twenty four (24) ormore hours after the concrete has been poured. All forms shall be cleaned andoiled each time they are used. In the pouring of sections, construction joints shallbe located at expansion joints. Should it be necessary to make construction jointsbeyond the expansion joint, such construction joints shall be made at the locationof contraction joints.(ii)Joints(a) Longitudinal Joint: The longitudinal joint running at the centre line of thepavement shall be formed in accordance with the section and dimension shownon the approved drawings. Before concreting the next lane, the longitudinal jointshall be painted with two (2) coats of liquid asphalt applied at a temperature of65 0 to 135 0 Fahrenheit. The asphalt should be completely dry before commencingpour to the next lane.Ghorasal 200 MW to 300 MW Gas Turbine Peaking Power Plant Project (Vol-2 of 3)177