How to Perform Underwater Concreting Using Tremie Method?

The Tremie method is a type of underwater concreting that is used to establish a seal before the initial pour of the concrete.The underwater concreting process involves placing concrete under the water. It includes lowering the concrete, transferring the mix to the underwater floor, laying aggregate, grouting, and pumping concrete directly into place. 

Fig.1. Underwater Concreting Using Tremie Method

Image Credits: www.consultmarine.com.

Tremie's method of concreting is one of the convenient methods of pouring a large amount of high-flowable concrete. This article explores the features and procedure behind tremie method for underwater concrete construction. 

Tremie Method of Underwater Concreting

Fig. 2 below shows the general arrangement of the tremie underwater concreting process. As shown in the figure, the prepared underwater concrete is moved to the hopper either using pumping, a belt conveyor, or skips. There is a tremie pipe whose top end is connected to a hopper and the lower end is submerged in fresh concrete. Tremie pipe is used to place the concrete at the exact location from the hopper to the surface of concreting.

Fig.2. Tremie Method of Underwater Concreting

The tremie pipe is immersed to the lower end to prevent intermixing of both the concrete and water.

 Fig.3. Hopper - Underwater Concreting Using Tremie Method

Image Credits: www.consultmarine.com.

What is the Process of Tremie Method of Underwater Concreting?

The complete process of the tremie method of concreting has the following arrangement:

1. Tremie Equipment
2. Tremie Seal
3.  Concrete Placement

The tremie equipment is a tremie pipe which is a water-tight pipe usually made of composite metallic pipe having a diameter between 20 to 25 cm. The pipe is equipment that is capable of easy coupling for an increase or decrease in its length.

Fig.4. Pouring Concrete in Hopper of a Tremie Pipe
Image Credits: www.consultmarine.com

To avoid the intermixing of the concrete and water, a wooden plug is used to seal the end of the pipe. This arrangement helps prevent the entering of water into the pipe and keeps it dry. Once the pipe is located in its intended position, the seal is broken, after which the concrete flows out of the pipe. Hereafter, the concrete accumulated around the lower end of the pipe creates a seal.

Fig.5. Pouring Concrete in Hopper of a Tremie Pipe
Image Credits: www.consultmarine.com

During the process, sheet piles from work are driven inside the water and the tremie pipe is lowered into position. The discharge end is kept fully submerged in the freshly placed concrete. At regular intervals, the tremie pipe is lifted up and a slight jerk is given by a winch and the pulley arrangement to discharge the concrete down.

During the whole process, exclude concreting air and water by maintaining a pipe full of concrete all the time.

Also Read:

1. What is Underwater Concreting
2. Cold Weather Concreting Tips and Precautions to Follow