Concreting should be preceded by the determination by a specialized laboratory of concrete components and its recipe as well as checking the characteristics of the mixture produced under construction conditions.. All concrete additives (plasticizers, sealants and set retarders) should have approvals and be laboratory tested.
Water, in which the concrete structure is formed, the bottom and the inside of the bulkhead wall or underwater formwork should be clean. There should be no chemicals in the water that are corrosive to the concrete. The bottom should be cleaned of sediments and weak soil and leveled. The hollows in the bottom of the weak soil removed are filled with coarse aggregate. The water at the underwater concreting site should be stationary. Therefore, close all openings in the formwork, to prevent the flow of water with the mixture stored in it. All water turbulences must be prevented and fresh concrete must be protected from tidal movements and water currents.
Do not allow water to overflow through the top of the bulkhead or the box, in which the structure was concreted.
Because a certain mixing of concrete with water at the surface of the structure cannot be avoided, therefore its top layer must be removed and this layer must be ignored in the strength calculations and in the structural durability assessment.
In winter, you need a concrete mix (or its ingredients) heat up, that the temperature of the concrete after laying under water is at least + 5°C. When the air temperature is below -15 ° C, the funnel and the top of the fill pipe should be heated with a steam heater, air or electric.