Underwater concreting is a specialized technique used in the construction of structures in the presence of water, whether in freshwater or saltwater environments. This method is essential for the construction and repair of dams, retaining structures, submerged foundations, and various other maritime and riverine applications. Here, we explore the main characteristics, methods, and necessary precautions for carrying out underwater concreting.
What is Submerged Concrete?
Submerged concrete is the term used to describe concrete applied in environments with the presence of water. This type of concreting is common in coastal regions, aquifers, and in projects involving submerged structures, such as:
- Maritime structures in saltwater (docks, piers, breakwaters).
- Freshwater river structures (bridges, dams).
- Retaining walls and foundations in areas with water present.
Method of Execution: The Hopper
- Hopper: It transports and deposits the concrete in a controlled manner, filling the formwork from the bottom up.
- Molds: Made of wood or metal, designed to withstand the pressure of water and concrete.
Care for Submerged Concrete
- Concrete Quality: It must have the right consistency and composition to resist segregation and washing, with the use of additives to improve workability.
- Control of Concrete Pouring Speed: It must be continuous and controlled to prevent cold joints and ensure good compaction.
- Contamination Prevention: To protect the concrete from sediment and other materials present in the water.
Specific Applications and Selection Conditions
- Stakes: Ensure complete filling to avoid gaps.
- Caissons: Continuous pumping to prevent segregation.
- Sacadeiras: Used in hard-to-reach areas or where a hopper is not feasible.
Conditions for Choosing the Method
- Nature of the Work: Complexity and type of structure.
- Aquatic Environment: Depth, presence of currents, and water type.
- Available Resources: Equipment and technology at the construction site.
- Standards and Regulations: Compliance with technical standards and local regulations.
Conclusion
Underwater concreting is a crucial technique for many civil engineering projects, especially those involving submerged structures or structures in constant contact with water. Using methods such as the tremie and taking specific care in choosing materials and controlling the concreting process, it is possible to guarantee the durability and safety of the constructed structures.
