The principle of the Tremie method is to bring the concrete through a pipe into the concrete to pour, thus avoiding contact with the surrounding water. Before the concrete is poured into the Tremie pipe, a plug that keeps the concrete separate from the water is placed in the pipe. When the hand truck reaches the bottom, the pipe is lifted, so that the concrete flows out. Concrete is continuously fed to the Tremie pipe through a Tremie and the pipe is lifted as the concrete level rises. 1s cement added continuously until the end of the casting.
The Tremie method is one of the most commonly used methods for cementing underwater. In this method, a long steel tube (called a Tremie ) with a diameter of 15 to 30 cm is inserted vertically into the water. The hose should be long enough to reach the water bed while keeping the end above the water level. The Tremie is therefore equipped with a Tremie at the upper end to pour the concrete inside the pipe. The lower end of the Tremie tube must be closed with a check valve before inserting it into the water. After that, the freshly mixed concrete is poured using the Tremie. When the concrete is poured, it displaces the air and water present in the pipe and eventually reaches the bed.
Tremie method During the pouring time, the shaker is continuously raised, keeping the lower end of the pipe in the already poured concrete. To reduce the loss of additional cement underwater, a rich concrete mix should always be used. Therefore, concrete laid underwater should never be compacted or consolidated.
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A Tremie Pipe is a system of pipes used to place concrete underwater. Its main application is in pile work, basements, diaphragms, caissons, underwater foundations, etc. A Tremie tube is made of a plastic tube or rigid metallic material and the diameter of the tube is between 20 and 30 cm. In the lower discharge bucket, the concrete is sucked through the water into a sealed box or bucket, and when it reaches the final place of deposit, the lower bucket mechanism automatically opens and all the concrete is slowly dumped. In some situations, a dry or semi-dry mixture of cement, fine and coarse aggregate is poured into bags of cement, and this bagged concrete is deposited on the bed underwater. Even this method does not give satisfactory concrete, because the concrete mass will be filled with voids strewn with putrescible jute bags. The Tremie tube method for pouring concrete underwater is a satisfactory and widely used method in the world.
The word “tremie” comes from the French word
Underwater Concreting Of Tremie Method
A tremie tube is a tube with a diameter of about 20 cm that can easily mate for an increase or decrease in length. A large funnel is mounted in the upper part of the tremie tube which allows the concrete to be poured quickly. The lower end is closed with a cap or a sheet of polyethylene cm thick or material and brought underneath. The water is kept calm where the concrete will be laid. As the end is blocked, there will be no water entering the Concrete should have a sag about 15-20cm high in the funnel. When the entire length of the pipe is filled with concrete, the shaker pipe is lifted and a slight shake is given by a winch and pulley.
When the pipe is lifted and shaken, due to the weight of the concrete, the bottom plug falls off and the concrete is unloaded. At this stage, special care must be taken that the end of the Tremie pipe remains inside the concrete so that no water enters the pipe from below. In other words, the hollyhock tube remains clogged at the lower end of the concrete. Again, concrete is poured over the funnel and when the entire length of the tremie pipe is filled with concrete, the pipe is again slightly raised and slightly pulled. Always ensure that the lower end of the tremie tube is fully embedded in the wet concrete. Concrete in the tube for a short time is discharged. This sequence continues up to the level of the concrete above the water level.
This method, when done correctly, has the advantage that the concrete is not affected by water except for the top layer. The top layer is rubbed or cut to remove the affected concrete at the end of the entire operation.
Features Of Tremie Pipe Concreting
During pouring, pumping of water should not be allowed Cement particles if simultaneous pumping of water is performed Submarine concrete should not be compacted, because concrete is automatically compacted by the hydrostatic pressure of the water. of a consistency that does not normally require compaction.
One of the disadvantages of underwater casting in this method is that a high water/cement ratio is required for a high consistency which reduces the strength of the concrete. But currently, with the use of superplasticizer, this is not a constraint. Concrete with a water/cement ratio of up to 0.3 or even less can be placed with the Tremie method.
Another, not so commonly used, method of placing concrete underwater is the process of grouting ready-mixed aggregates. The coarse aggregate is unloaded to take the full size of the concrete mass.
The prepared cement mortar is injected through the pipe, which extends to the bottom of the aggregate bed. this method of stuffing foundations is often adopted.
Concrete can also be placed underwater through the use of concrete pipes and pumps. , the cork is ejected; the concrete surrounding the lower end of the pipe seals the pipe.
Pumping is done against the pressure of the plug at the lower end. When the required pumping force is too great to overcome the pressure, the pipe is withdrawn and the operation is repeated.