How to pour concrete in water

Is concrete poured into water? Yes, of course, and this can be done absolutely calmly, only the work on underwater concreting has its own specifics. About whether the concrete will harden in the water and how to achieve this, and we'll talk in the article below.

Variants of work

They can be done in two ways:

• at a small depth, where there are no tides, and there are minor waves, the mortar is lowered through a funnel in the cavity, fenced with special bridges, or concrete is poured into the water;
• at quite impressive depths, in places where the waves can be very strong, caissons become a reliable assistant in the work of concreting. Concrete mass in such caissons move through shafts or pipes. Better not with their own hands, and concrete pumps.

How to fill, what is the water standard for concrete and mortars? Consider this process in more detail.

Method number 1

The instruction is as follows:

1. It begins with the fact that in the place where the proposed construction will be erected, the rows of piles are driven in (sheet piling are used). This makes it possible to avoid dewatering work.
2. Then between them through a funnel throw concrete.

Tip: if the base under the concrete solution has insufficient density, for example, from sketched stones. In this case, it must first be firmly nicked, then covered with a sheet, the edges of which will be bent upwards. Thanks to such measures, the solution will not be able to seep into the rubble, and concreting will take place much better.

Ready-made concrete

After the base is ready, you need to prepare a solution. It is important to remember that he needs some time to rest. At the same time it should not get direct sunlight or moisture.

If the solution is sustained, then it will reach the desired consistency for immersion in water: it will grasp a little and will not be greatly eroded in water. This solution preparation method was first used by Kinipple, an engineer from the UK.

In this way, he was able to avoid unnecessary costs for the construction of a system that would save the concrete solution from erosion. Kinipple put the solution under water, which is already half hardened.

In addition, the engineer has provided technology to protect it from the force of waves and undercurrents. For this, he covered the outer side of the concrete surface with a thick linen cloth (canvas).

Tip: for the core of such a structure, use an unsaturated solution, but the outside part requires a saturated one, while its thickness should be at least 1 m.

The compositions are as follows:

Recommendations:

1. Depending on the characteristics of the rate of hardening of the concrete mass, it is necessary to allocate the time between mixing it and moving it into water.. It is important to calculate the time in the most optimal way so that when sinking the concrete does not erode too much. Otherwise, part of the cement will be lost, which will adversely affect the quality of the structure.

1. It is also important to ensure that the concrete mass does not become too solid, because in this case it will not contact tightly with the solution that was immersed earlier and will not become monolithic. On those underwater areas that are subject to powerful impacts of the waves, to a strong current, before lowering the concrete into the water, add a small part of the quick-hardening cement.

1. In addition, the concrete lowered into the water needs compaction. To ensure this, his ram. The top of the tamper is above the water level, taking the blows of the instrument with which the tamper is rammed. Remember that tamping should be done very carefully, because if you overdo it, too much vibration and waves will inevitably lead to the erosion of concrete.

In order to obtain such concrete, it will be necessary to mix cement with pure pitch in a ratio of 1 to 2.5.

Advice: to the question whether the concrete passes water, can be answered - depends on the composition, so it can be used to build water tanks.

Method number 2

1. Near the site where it is planned to build the necessary concrete structure, for example, a dam, with the help of dredgers it is necessary to dig two ditches at the bottom. They should pour semi-hardened concrete, straight into the water. The result will be two trees that will reach the level of low waters.

Tip: before starting their installation, assess the condition of the reservoir in the selected area and the quality of the cement. The price of the latter cannot be low.

1. To remove these shafts, the concrete mass is lowered into the water in kuli. This idea is not accidental, their value is that in the process they are able to form a monolith. After sketching cement for the shafts, iron piles are clogged. Do it at an angle to get the slopes.

1. Connect the piles with each other with special iron rods in which eyelets are made. To keep them at the right angle, put on a steel cable from above, which you attach to the dead anchors.

Tip: so that during strong waves the concrete is not washed out, on the inside of the piles, lay the boards covered with canvas.

1. Over the entire length of the structure, install partitions of concrete. The material for them should be at the stage when it begins to dry out and harden. This will allow to form a monolithic part with the lower layers.

This technique allows you to save, as the solidity is guaranteed even with the use of low-saturated concrete. However, when working with low-saturated concrete, it is important to know that its constituent parts must mix very well and form a homogeneous mass. In addition, you should know that if there is a lot of water in concrete, its “graspability” will be greatly disturbed.

Tip: immerse it in water is necessary after this mass began to clutch. If weather conditions are unfavorable (wind, strong waves) or concreting is carried out at a great depth, the work is carried out inside the caissons.

After the ground under the base is prepared, install partitions 1–1.2 m thick around the chamber - from the roof to the bottom. Make the walls of vertically standing boards, which then remove as the concrete hardens. Under the ceiling, treat the solution with a flat rammer.

Tip: it is best to lay the concrete in layers, while it is not necessary to begin the process of laying a new layer until the previous one has dried.

Hardening one takes 5-6 hours. Lower the concrete solution through special pipes, which are fitted with valves at the top and bottom.

Trumpet

In underwater concreting a pipe is a very important device. Opening the upper valve, you ensure that part of the concrete gets into it, after which it should be closed.

The air pressure in the device and in the chamber is equalized with the help of a crane that connects them. Then you need to open the valve located at the bottom so that the concrete sinks into the water until it is sufficient to resist the pressure of the water.

Tip: if you do not know how much water you need to spend per cube of concrete, take an average of 125 liters.

After that, the solution is already lowered through the mines. To reduce the consumption of material to fill the caisson, you can use the stones from the bottom, where the work is done, just fill them from above. At the moment, the maximum depth of underwater concreting works is no more than 30 m.

Conclusion

Concreting in water is an important stage in the construction of hydraulic structures. With their help, it is possible to create dams, dams and other structures that do not collapse under the onslaught of waves. The article was about two methods of casting - using piles and concrete shafts (ascending solution).

The video in this article will help you find additional information on this topic.