Repair and Rehabilitation of bridge located at Lowairpoa Rangamati Kanmun Road(Lowairpoa-Kanmun) at Ch.77.80 Km under Mukhya Mantrir Path Nabikaran Achani (MMPNA) for the year 2023-24

Amount

Chipping of deteriorated concrete and removal of all loose & friable materials and fully exposing rusted reinforcement followed by proper cleaning and removing of rusts and other foreign materials using sand blasting/emery clothes/wire brush etc. includingbformwork as directed and specified byy the department complete

Replacement of corroded reinforcement by cutting and welding new reinforcement of minimum 25mm dia including lapping on both sides to the specified length as directed and as per relevant IS/IRC codes and cost of gas, welding rods, higher charge of welding machines etc including formwork as required (Reinforcement to be measured and paid seperately)

Supplying and applying two coats of zinc rich anti corrosive protective coating with nitozinc primer of fosroc or equivalent @ 0.20 Litre per sqm over thoroughly cleaned & prepared steel bar including formork as directed and specified by the department complete.

Supplying and applying Epoxy based bonding agent Nitobond EP of Forsoc Chemicals or Masterbrace 1414 of BASF/Rearmbond EBA or equivalent @ 0.50 Lit per sqm after totally saturating the cleaned concrete surface with clean water for proper bonding of old and new concrete including formwork as specified and directed by the department complete.

Patching of damaged concrete surface with structural grade polymer modified reinstatement mortar to like Fosroc Renderoc S2/Rearm crete RMHS or equivalent at a thickness of 10 to 20 mm as per instruction of manufracturer and as approved by the engineer. The prepacked repair mortar should have a compressive strength 45 N/Sqmm, Flexture strength 8 N/Sqmm at 28 Days

Repair of joint Grooves with Epoxy Mortar Repair of spalled joint grooves of contraction joints, longitudinal joints and expansion joints in concrete pavements using epoxy mortar or epoxy concrete

Providing & fixing 16mm dia MS nozzles in a grid of 1m c/c up to the half of the thickness of the concrete structure. A grout slurry of neat cement & chloride free expanding grout cebex 100 of Fosroc Chemicals/Mastergrout CPG-1 of Choksey Chemicals/Armgrout additive of Myk arment/Masterflow 150 of BASF or equivalent @0.5% by weight of cement water cement ratio 0.35 to 0.40 and viscosity not more than 1.02 centipoise with grouting pressure till the refusal of injection grout Mastergrout CPG-1. The grouting operation pressure shall be 2Kg/sq.cm. Cutting the exposed nozzle after the grouting with a good cutter to make the surface free from the grouting pipes and to seal the gap with plugging compound Masterplug of choksey Chemicals as per the specification and the direction of the department complete including formwork.

Providing and inserting nipples with approved fixing compound after drilling holes for grouting as per Technical specifications including subsequent cutting/removal and sealing of the hole as necessary of nipples after completion of grouting with Cement/Epoxy.

Sealing of crack/porous concrete with Epoxy Grout by injection through nipples complete as per clause 2803.1

Concreting of the structure with free flow nonshrink cementitious microconcrete with Rendorec RG of Fosroc/Rearmcrete MC or equivalent after proper mixing with cleanwater including formwork followed by proper curing for 28 days as per manufacturer's specifications complete and as directed by the Department.

Structural Strengthening with Carbon Fibre: Patching in depression of concrete surface wherever necessary by laying epoxy putty , Nitocote VF of Fosroc Chemicals or equivalent @ 1 Lit per sqm after proper surface preparation and proper scraping of concrete protrusion as specified and directed by the department complete including formwork.

Applying Nitowrap 410 saturant Fosroc Chemicals or equivalent with wet film thickness @ 250 microns (0.27Lit per sqm) over a coat of saturant epoxy primer Nitowrap 30 of Fosroc Chemicals or equivalent @0.11 Lit per sqm with brush followed by fixing carbon fibre composite system Nitowrap EP (CF) of Fosroc Chemicals or equivalent by pressing on the saturant and impregnate the same by applying a final coat of Nitowrap 410 saturant Fosroc Chemicals or equivalent as specified and directed by the department complete including formwork.

Applying two coats of UV resistant coating Nitowrap 512 of Fosroc Chemicals or equivalent over fibre system having wet film thickness of 100 micron @ 0.11 Lit per sqm as specified and directed by the department complete including formwork.

Providing and applying Dekguard E2000 or Masterseal 878 of BASF or Rearmcoat anticarb or equivalent a high performance anticarbonation protective coating system, over the primed surface using an airless sprey or roller at right angle to each other @ covarage 5 Sqm per litre per coat @200 micron wft/100 micron DFT with an intercoat period of minimum 12 hours @ 35⁰C. The covarage per litre for two coat shall be 2.5 Sqm @200 micron DFT. The protective coating system should have Co2 diffusion resistance not less than 240 mm equivalent of air thickness and 60 cm equivalent of 30 N concrete along with water vapour transmission resistance of less than 1m (taywood method), the coating should have static crack accomodation of not less than 2mm (BRE) and adhesion greater than 1 N/sqmm as per BS 1881.

Supplying and fixing of rebaring chemicals Fosroc Lokfix E55 S-venylester chemical anchor grout or equivalent for various diameter of reinforcement bar at provided embedment depth as per manufacturer specification and instructions for use in concrete applications as directed by engineer in charge.(i) 8 mm dia re-bar fastners.

Supplying and fixing of rebaring chemicals Fosroc Lokfix E55 S-venylester chemical anchor grout or equivalent for various diameter of reinforcement bar at provided embedment depth as per manufacturer specification and instructions for use in concrete applications as directed by engineer in charge.(ii) 12 mm dia re-bar fastners.

Painting on concrete surface (Providing and applying 2 coats of water based cement paint to unplastered concrete surface after cleaning the surface of dirt, dust, oil, grease, efflorescence and applying paint @ of 1 litre for 2 Sq.m. )

For RCC Railing Non-destrucitive testing with Ultrasonic Pulse Velocity Meter with data storage facility for detection of cracks, voids and other imperfections in Reinforced concrete structures and furnishing the findings thereof in proper comprehensible format, complete as directed by the department.

Conducting Concrete Core tests of 75mm diacores, on concrete structure, as per stipulated procedures, for determination the equivalent cube compressive strength, concrete of the structures including preparation and furnishing the report showing the findings thereof in proper comprehensible format, complete as directed by the departmemnt.

BIMAL SINHA