Tremie method of underwater concreting - Introduction, procedure and properties

    In the case of basements, sewerage and marine works, concrete needs to be placed under water. In this situation, a special type of concreting method is used which is called Tremie method.

What is tremie?

  A tremie is a water - tight pipe having diameter of 200 - 250 mm. It has a funnel - shaped hopper at its upper end and a loose plug at the bottom for discharge end. Tremie pipe is supported by a crane above the water level which is also used to lift up the pipe. It is easy to adjust the length of tremie pipe.

What are the procedure of tremie method?

Tremie method includes following procedure -

  • At first, the tremie pipe is taken below the water, closing the bottom end with plug, by crane.
  • Then it is made to rest at the point where the concrete has to be placed.
  • After that, concrete having slump about 15 to 20 cm is poured into the funnel.
  • When whole length of pipe is lifted up using power hoist. It is lifted up such that the bottom end of pipe lies inside the concrete. It prevents the entry of water into the pipe.
  • Same procedure is repeated continuously till concrete comes above water level.
  • At the end, the top layer of concrete is cut off.

What are the properties of Tremie concrete method ?
   
Tremie method of underwater concreting carries following properties -
  • No compaction requires, because hydrostatic pressure of water does the same.
  • Consistency of concrete is maintained such that it gets self compacted.
  • A high w/c ratio is required to get high consistency.
  • Due to high w/c ratio, strength of concrete gets reduced.
  • Quantity of course aggregate should be 1.5 to 2 times of fine aggregate.
Thank you.



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