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Methods of Concreting Under Water

Methods of Concreting Under Water

  1. Tremie pipe Method:
  2. Bucket Method:
  3. Grouting Method:
  4. Bags stacking Methods:

1)Tremie pipe Method:

The tremie solid situation strategy utilizes a vertical or almost vertical pipe, through which concrete is set by gravity feed underneath water level. The lower end of the pipe is kept drenched in crisp cement with the goal that solid ascending from the base dislodges the water, in this way restricting washing out of the bond substance of the new concrete to the uncovered upper surface. The upper end of the tremie pipe is kept over the water level amid the pour and is given a cone shaped container for cluster stacking, or cement might be siphoned into the highest point of the tremie pipe. Concrete must be poured at a rate which abstains from setting in the tremie.

2) Bucket Method:

In this strategy the solid is stored submerged by a base opening container. The cans for the most part are fitted with base roller or drop base doors as appeared in Fig.18.13. The door opens uninhibitedly outward when stumbled. The pail is filled totally with cement and its best secured with a canvas fabric or gunny sack and brought gradually down to keep away from back­wash or unsettling influence to concrete as the can is brought down into the water.

The can is brought down by a crane upto the base surface of the solid and afterward opened either by a reasonable game plan from the best or by a jumper. It is basic that the solid be released straightforwardly superficially on which it is to be saved.

Advantages:

This technique is found to have the accompanying preferences:

I. Relatively lean blends might be utilized given adequate versatility is held.

ii. No structure work is fundamental in this technique.

Disadvantages:

I. This technique is moderate and arduous as the exact situating of the packs set up must be cultivated by the jumpers.

ii. Voids in adjoining sacks are hard to fill.

iii. There is small holding other than created by the mechanical interlock between packs.

iv. The technique similarly is exorbitant as more work is associated with filling and tying them.

3) Grouting Method:

These pens are laid vertically over the full zone to be cemented with the end goal that the separation between the focuses of the pens and furthermore to the essences of the solid ought not surpass one meter. The measure of the stone total should nor be under 50 mm nor in excess of 200 mm. This total ought to be wetted before storing it outside the steel confines over the full region and tallness to be cemented. While saving the total, care ought to be taken that no pen is uprooted from its position.

Subsequent to storing the total, the concrete sand grout of 1:2 extent and water/bond proportion at least 0.6 and not more than 0.9 is set up in a mechanical blender. The greatest size of sand might be 5 mm and the concrete sand extent may shift from 1:1.5 to 1:4 contingent on the quality prerequisites and significance of the work.

In the wake of grouting the entire territory for a stature of around 60 cms, a similar activity is rehashed for the following layer of 60 cm and the methodology is rehashed till the grouting is finished upto the ideal tallness. The grout to be sent down ought to be adequate to fill every one of the voids. The volume of voids might be accepted as 55% of the volume to be cemented or discovered tentatively. Beyond what many would consider possible cement ought not be bothered while it is kept, this will limit the arrangement of laitence.

4) Bags stacking Methods:

The packs are tied so that they can be suited promptly in a profile of the surface on which they are put. The legitimately filled sacks are brought down into the water and set cautiously in header and stretcher courses as in block workmanship development with the assistance of jumpers so the entire mass is interlocked.

advantages:

This technique is found to have the accompanying points of interest:

I. Nearly lean blends might be utilized given adequate versatility is held.

ii. No structure work is important in this technique.

Disadvantages:

I. This technique is moderate and arduous as the precise situating of the packs set up must be cultivated by the jumpers.

ii. Voids in contiguous packs are hard to fill.

iii. There is small holding other than created by the mechanical interlock between packs.

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