Here are the main substances and factors that can cause deterioration and damage to concrete:
1. Acids
Acids such as hydrochloric, sulfuric, nitric, and others react with the components of concrete, breaking down its structure. Even weak acids can cause significant damage over time.
2. Alkalis
Strong alkalis, such as sodium hydroxide (caustic soda), can also etch and soften concrete.
3. Salts
Salts like chlorides and sulfates can cause corrosion of reinforcing steel in reinforced concrete, leading to cracking and spalling of the concrete.
4. Carbon Dioxide
Carbon dioxide from the air can react with calcium hydroxide in concrete, reducing its strength and causing carbonation.
5. Water
Excessive moisture and freeze-thaw cycles can lead to cracking, scaling, and spalling of concrete.
6. High Temperatures
Exposure to high temperatures, such as in a fire, can cause loss of strength and disintegration of concrete.
7. Mechanical Loads
Excessive mechanical loads, impacts, or vibrations can result in cracking and failure of concrete structures.
To protect concrete from these deteriorating agents, specialized admixtures, coatings, and proper concrete mix design based on the exposure conditions are used. Timely inspection and repair also help prevent the deterioration of concrete structures.