Repair and Restoraretion of HL Bridge B over Mahanadi River at Mirzeipur on Pratapnagari-Athanga Road under Kataka (RandB) Division II for the year 2024 25

Chipping of unsound/weak concrete material from slabs, beams, columns etc. with manual Chisel and/ or by standard power driven percussion type or of approved make including tapering of all edges, making square shoulders of cavities including cleaning the exposed concrete surface and reinforcement with wire brushes etc. and disposal of debris for all lead and lifts all complete as per direction of Engineer-In-Charge.(75 mm average thickness)

50 mm average thickness

Cleaning of exposed concrete surface of sticking material including loose and foreign material by sand blasting with coarse sand followed by and including cleaning with oil free air blast as per direction of Engineer in charge.

Providing and applying of anticorrosive treatment to exposed structural reinforcement by two coats of IPNET RB or equivalent with time interval of minimum 8 -10 hours between each coat after the application of two coats of alkaline rust converting primer. The application shall be done by brush or spray after cleaning existing reinforcement with wire / rotary wire brush to make the surfaces free from loose material, dirt, traces of corrosion etc. and thoroughly washing with water and allowing it to dry inclusive of all labour, materials, equipment etc. complete in all respect as per specifications and instructions of Engineer in Charge.

Providing, mixing and applying bonding coat of approved adhesive on chipped portion of RCC as per specifications and direction of Engineer-In-charge complete in all respect.(Epoxy bonding adhesive having coverage 2.20 sqm/kg of approved make)

Cleaning of reinforcement from rust from the reinforcing bars to give it a total rust free steel surface by using alkaline chemical rust remover of approved make with paint brush and removing loose particles after 24 hours of its application with wire brush and thoroughly washing with water and allowing it to dry, all complete as per direction of Engineer-In-Charge.(Up to 12 mm diameter (Quantity taken for estimate purpose approximately. Quantity may vary as per actual work) @ 50Rmt per span))

Bars above 12 mm diameter (Quantity taken for estimate purpose approximately. Quantity may vary as per actual work) @ 50 Rmt per span)

Shotcreting R.C.C. columns, beams, and slab etc. in layers with approved design mix concrete having the specified minimum characteristic compressive strength [with ordinary portland cement, coarse sand and graded stone aggregate of 10 mm maximum size in proportion as per design criteria] including the cost of centering and shuttering at edges and corners etc. as directed by Engineer- in-Charge. Note: Rate shall be include the providing necessary ground wire etc. The levelling gauges, if used, shall be paid for separately. Payment under this item shall be made only after proper wet curing has been done and surface has been satisfactorily evaluated by sounding/tapping with a blunt metal instrument.(75 mm thick in Grade M 25 with cement content not less than 330 kg per cum)

Providing and fixing hard drawn steel wire fabric of size 75 x 25 mm mesh or other suitable size wire mesh to be fixed & firmly anchored to the concrete surface by means of "L"shaped mild steel shear key welded with existing reinforcement including the cost of materials, labour, tool & plants as approved by the Engineer-In-Charge.

Providing , mixing and applying SBR polymer (of approved make) modified cement mortar in proportion of 1:4 (1 cement: 4 graded coarse sand with polymer minimum 2% by wt of cement used) as per specifications and directions of Engineer-in-charge. Note: Measurement and payment: The pre-measurement of thickness shall be done just after the surface preparation is completed and payment under this item shall be made only after proper wet curing has been done and surface has been satisfactory evaluated by sounding / tapping with a blunt metal instrument and/ or the 75mm size cube crushing strength at the end of 28 days to be not less than 30 N /mm2 .(50mm thickness in 3 Layers)