Tamil Nadu Transmission Corporation Limited Tender

Labour charges for chipping the spalled and old concrete of the slab. Check for the phenopthaline test and if there is no change in colour chip the same further down until, reaching the good or uncontaminated concrete. Clean the surface and make sure that surface is clean and free from loose particle at an average thickness of 50mm.

SHEAR CONNECTOR

Drilling 10mm dia holes up to a depth of 60mm maximum and fix 8mm dia L shaped anchor rods as shear connectors atwhere ever reqired on the surfaces of the slab or any other structural member as the case may be. Clean the same using water and make sure that there is no fine particle present in the hole.Mix the base and hardner of the polyester resin with the spatulathoroughly. Fill the drilled and cleaned holes to a minimum depth of 1/3rd of the hole with the preparedpolyester resin. Make sure that the resin has reached till the end of the hole. At this stage push the shear connector gently in to the hole and finish the excess resin which comes out of the hole and allow the shear connector to be undisturbed for minimum 20 minutes - complete.

PROVISION OF ADDITIONAL REINFORCEMENT

Check the diameter of the existing rebar and if the diameter is less than 30% of the original diameter and provide additional reinforcement. Cut the required dia bars as main reinforcement to the required length with proper development length. Tie them to the prefixed shear connectors so that the additional rebar acts monolithic with the existing ones . In case of the shear reinforcement also, if the diameter of the reabrs are reduced, provide 8mm dia stirrups in the form of 2 "U" shaped. Tie them properly so that it has the tight contact with the main bars.

PRIMING OF REINFORCEMENT BARS

Clean the rebars using the rust remover if there exists any rust, otherwise clean the rebar free of foreign material. Mix the base and hardner of the zinc rich epoxy resin mechanically using a slow speed heavy duty drilling machine fitted with mixing paddle. Apply the mixed materials to the cleaned rebar and allow it to dry complete.

FORM WORK

Providing slurry tight form work including strutting, propping, etc., which should not deform or leak due to pressure of micro concrete shall be fabricated in position using 6mm thick commercial plywood as per the required line and length at all different floor levels as per the standard specification-complete. Form work should be rigid to prevent loss of micro concrete at all stages & appropriate to the methods of placing & compacting as per standard specification. It should be made of suitable material. The form work should be coated with shutter release agent prior to fixing. The rate shall include the cost of all the operations and etc.,

MICROCONCRETE

Micro Concreting for the damaged structural element like slab/beam/column by Stocking sufficient quantity of micro concrete and 12mm downgraded chips on site to enable the completion of the pouring in a continuous operation. An approved concrete mixer or a slow speed heavy duty drilling machine fitted with mixing paddle shall be used. Mix the micro concrete and the 12mm down grade chips in the ratio of 1: 0.5 (one part of Rendroc RG and 0.5 part 12mm down chip) by weight with required quantity of water powder ratio 0.16 and place the same to the prefixed formwork well before the epoxy jointing compound dries up. Remove the formwork after 24 hours in the case of columns and after a period of 72 hours in the case of slab and beam and check for any surface defects and if so apply the polymer modified mortar - complete. The rate shall include the cost of all the operations and complete.

PROTECTIVE COATING

Prepare the surface neatly ensuring there is no fine dust accumlated over the area, and wash the surface and allow it to dry prior to the application of the primer. Mix the high performacne, aliphatic acrylate based anticarbonation proteive coating primer Fosroc Deckguard S Primer to the prepared surface and allow the same ro dry over a period of 2 hours over which Deckguard S top coat shall be applied in two mutually perpendicular directions in order to obtain a DFT of 150 microns over the prepared area.

GST 18 % to be entered by the Biders