Corrosion of reinforcement is a major problem that affects the durability and safety of reinforced concrete structures. Corrosion is a natural process that occurs when metal reacts with the environment and can result in serious structural damage and even collapse. In this article we discuss the causes, effects and prevention of rebar corrosion.
Causes of reinforcement corrosion
The most common cause of reinforcement corrosion is exposure to chloride ions and carbonation. Chlorides can penetrate concrete through cracks, pores and other defects and react with the reinforcement metal. It was found that chloride penetration can occur in cracks around 0.05 mm wide, leading to corrosion of the reinforcement and shortening the useful life of the structure.
Carbonation occurs when carbon dioxide in the air reacts with the alkaline cement in concrete, causing the pH of the concrete to drop and it to become more acidic. This acidic environment can cause corrosion of the rebar metal.
Other factors that can contribute to rebar corrosion include:
- Low concrete cover: Concrete cover refers to the thickness of the concrete between the reinforcement and the surface of the structure. If the coverage is too low, the reinforcement is more exposed to the environment and corrosion can occur more easily.
- Poor-quality concrete: Poor-quality concrete can result in cracks, voids, and other defects that allow water and other corrosive substances to penetrate the concrete.
- Electrical potential: Corrosion can also occur due to the difference in electrical potential between the reinforcement and other metals that come into contact with it.
In addition to carbonation and chloride attacks, chemical attacks can also cause corrosion. Studying groundwater, water extracted from the ground and water used in construction is also very important to identify aggressive chemicals.
Effects of corrosion of reinforcement
Corrosion of reinforcement can have serious impacts on the durability and safety of reinforced concrete structures. The most common effects of corrosion include:
- Structural damage: can cause the reinforcement to lose its strength and ultimately fail. This can cause cracks, chips and even collapse of the structure.
- Cosmetic damage: Corrosion can also cause unsightly stains and rust spots on the surface of the structure, which can reduce its aesthetic appeal.
- Maintenance costs: Corrosion damage requires costly repairs and maintenance, which can place a significant financial burden on the building owner.
How to prevent reinforcement corrosion
Preventing reinforcement corrosion requires a multifaceted approach that takes into account the different causes of corrosion. Common preventive measures include:
- Proper design and construction: Design and construction practices that ensure adequate concrete coverage, correct concrete quality, and correct reinforcement installation can reduce the risk of corrosion.
- Use of Corrosion Inhibitors: To reduce the rate of corrosion, corrosion inhibitors can be added to concrete.
- Cathodic protection: Cathodic protection involves applying a small electrical current to the reinforcement, thereby reducing the rate of corrosion.
- Regular Maintenance: Regular structural inspections and maintenance can help detect and treat corrosion before it causes significant damage.
The most important aspect of construction planning is the safety and durability of the structure. Modern construction approaches emphasize durability compared to old standards.
The specification of the concrete, taking into account the exposure conditions, aims to improve the durability of the concrete. In this way, the intended service life is taken into account.
- Reinforcement cover
- Concrete quality
- Water-cement ratio
- Minimum cement content etc.
are specified taking into account durability aspects.
In summary, corrosion of reinforcement is a serious problem that can have a significant impact on the durability and safety of reinforced concrete structures. Understanding the causes and effects of corrosion and implementing effective preventative measures is critical to ensuring the long-term performance of these structures.
The article How to Prevent Corrosion could also be investigated for more information.