METHODOLOGY FOR APPLICATION OF ASPHALTO SEAL ON CONCRETE BRIDGE DECKS

 

APPLICATION OF ASPHALTO SEAL ON CONCRETE BRIDGE DECKS

1. Scope:

This work shall consist of furnishing and laying of 6mm thick Asphalto seal  on concrete bridge decks for water proofing.

2. Reference:

 Asphaltoseal Brochure.

3. Equipments:

Gas Cylinder, trowel, wire brushes, Gas cutter, measuring tape, knife, compressor, and wooden flat/PVC Pipe.

4. Materials:

Asphalto Seal: It is a water proofing membrane consists of high strength reinforcement in layers of heat resistant rubberized asphalt. The reinforcement and rubberized asphalt interact to form a tough membrane that remains flexible through a wide range of temperature and movements. The tacky rubberized asphalt assures quick adhesion to the deck.

·     Primer: It is a special primer which affords a good adhesion of the membrane to the concrete deck. It provides a tight water seal and the same time allows gases in the concrete to escape.

5. Procedure:

 The surface of the concrete bridge deck shall be water proofed and cleaned completely.

Make sure the bridge deck shall be free from dust, oil, protrusions, ribs, hooks, and nails, rebar^·s etc.

- Heat the surface to relief the moisture if any from the bridge deck.

- If any projections visible on the bridge deck, shall be cut completely to avoid puncture to the asphalt seal membrane.

·       Apply a coat of  Bitumen primer on the bridge deck surface at the rate of 200 to 250g/m² and allow it to dry completely for 30 to 45min.

   ·  The asphalto seal rolls shall be lined up and spread open over the deck area with proper side laps and end laps without any wrinkles.

·   The membrane shall be rolled back without changing its orientation.    The roll shall be unrolled once again and torch the underside with the help of  Gas cylinder evenly and sufficiently to cause surface melting.

·     The membrane shall be pressed with the help of wooden flat/PVC        Pipe from top of the membrane from inside to outside ensuring         that there is no entrapped air and proper adhesion to the deck.

·    The overlap joints shall be heated from the top to produce a thin bead of molten bitumen as the seam, should be smoothened out with a hot travel, ensuring a proper joint.

·    Make sure that the overlapping of the subsequent rolls shall be 50mm in longitudinal direction and 100mm in transverse direction.Repeat the same procedure for further layers and make a firm, water proof surface.

·  - Prior to allow the traffic over asphalt seal, a BC layer of 25mm thick shall be laid.

6. Safety Precautions:

  The deck area to be barricaded

  Workman shall wear PPE

  Only trained or with training^·s workmen shall be deployed