Maintenance and repairs including attending to leakage from terrace of Telephone Exchange Building Kaithamukku at Trivandrum

Amount

Providing and laying in position cement concrete of specified grade excluding the cost of centering and shuttering - All work up to plinth level :

1:2:4 (1 cement : 2 coarse sand(zone-III) : 4 graded stone aggregate 20 mm nominal size)

Repairs to plaster of thickness 12 mm to 20 mm in patches of area 2.5 sq. meters and under, including cutting the patch in proper shape, raking out joints and preparing and plastering the surface of the walls complete, including disposal of rubbish to the dumping ground , all complete as per directions of Engineer-In-Charge.

With cement mortar 1:4 (1 cement : 4 fine sand).

Providing and applying fibre reinforced elastomeric liquid water proofing membrane with resilient acrylic polymers having Sun Reflectivity Index (SRI) of 105 ( preferabaly Damp proof Ultra of Asian Paints) on top of concrete roof in three coats @10.76 litre/ 10 sqm. One coat of self-priming of elastomeric waterproofing liquid (dilution with water in the ratio of 3:1) and two coats of undiluted elastomeric waterproofing liquid (dry film thickness of complete application/system not less than 500 microns). The operation shall be carried out after scrapping and properly cleaning the surface to remove loose particles with wire brushes, complete in all respect as per the direction of Engineer-in-Charge.

Repairs to RCC Structural elements of framed or load bearing structure such as fins,facias,etc. excluding scaffolding up to floor VIII level with following operations :-

a) Removing all spalling concrete/cement mortar from the body frame by tapping the debonded concrete surface beyond 2 to 3 mm from the rusted reinforcing bar completely and cleaning all the reinforement bars.

b)Washing the cleaned reinforcing bar with clean water and applying one coat of anticorrosive Nitozinc primer on dried bar using paint brush.Care shall be taken to see that the applied primer makes an unbroken continuous film.

c) After cleaning the bar,applying one coat of bonding agent Nito AR on the exposed bar and concrete surface.

d)Covering the exposed bar as well as the affected concrete with high protection high strength Rendroc.

e)Covering the surface with modified polymer mortar to the required thickness (applied in layers not more than 25mm thick ) including finishing ect. completed and as directed by the Engineer in charge.

slab/ Beams/columns/fins

Pressure grouting of honey combed concrete by the following operations. Drill 12mm dia holes in the concrete in a grid pattern at required spacing as per site conditions but in no case exceeding 1m centre to centre. The depth of the drilling shall be adequate to pump the grout to the intended locations in predetermined areas. PVC nozzles shall be fixed in the holes drilled using a single compoment rapid setting compound Rendroc plug. Cement slurry mixed with expansive and plasticizing admixture Cebex 100 at the rate of 250gms per bag of cement

shall be injected through the prefixed nozzles under pressure using grout pump fill all possible pores and gaps left with in the concrete mass. When the flow of grout stops or when the grout flows out of the adjacent nozzle, pumping is stopped and the nozzle is tied up and allowed to set for 24 hours. The PVC nozzles shall be sealed off with a quick setting water proofing agent Rendroc plug. Grouting operation is carried out through the next nozzle fill the entire area is covered. The grouting holes shall be finished by removing the nozzles and finished flush with the surface etc all complete excluding scafolding charges as directed by the Engineer -in-charge at site.

L KRISHNANKUTTY (BID ID -786567)

C.SASIDHARAN ASARI (BID ID -786512)