Solid and waterproof concrete structures

The construction technologies of solid and waterproof concrete structures have a lot in common. Concrete is heated during solidification and hardening during the chemical reaction, and due to uneven temperature distribution in the structure, internal stresses can arise which may cause cracks in the concrete structure. Waterproof structures create a risk of water penetration through the concrete structure.

Solid structures cause high temperatures inside the structure and thus reduce the quality of the material. Therefore, it is necessary to ensure that the temperatures in the structure are not too high, and also that the temperature gradients are limited. There are several ways to achieve this. The most suitable way is to design concrete with little development of hydration heat. The casting of the structure can be slowed down so that the resulting heat can escape into the environment before the structure becomes completely cast. Then there are different ways of cooling the concrete and thus reducing its temperatures (e.g. cooling components or cooling the concrete mixture, or cooling the concrete structure).

In terms of the TIP research project supported by MIT, concrete with a low development of hydration heat has been developed in cooperation with TBG Metrostav, s.r.o., and it can be used for both solid and waterproof structures. Moreover, a technological procedure for the casting of massive structures has been developed in division 6. The result was a successful casting of thick boards (up to 1.6 m), e.g. during the construction of the ELI laser centre in Dolní Břežany. The technology has been successfully verified by a series of temperature measurements in the structure.

The use of the proposed technology made it possible to accelerate the casting of thick boards and walls because it was possible to cast them in one working pull.