1.Why Concrete Is Preferred?
Concrete is a combination of many different components, creating a solid material. Components of Concrete include: stone, gravel, sand, cement, adhesives, etc. and steel for reinforced Concrete works.
Basic properties of Concrete:
- Have durable structure and longevity.
- Good bearing of compressed force.
- Have good cohesion that is suitable for large constructions.
- Firm and majestic beauty.
- Easy to shape.
- Little wear and tear.
- Many other great features…
->Concrete is widely used in the construction of bridges...
2.Types of Popular Concrete
3.Current Concrete Status
Physicochemical processes, due to alkali-silica make ettringite crystals.
→Corrosion to concrete surfaces.
After a period of use, the climate, environmental factors ... impact makes the concrete surface appear many cracks, revealing the inner reinforcement.
→Reducing the life of the building..
Concrete surface adheres to moss, mold, water, moisture.
Carbonation reaction occurs between airborne CO2 and Ca (OH) 2 in Concrete.
→Reduce the alkali level in Concrete, activate the reinforcement corrosion process.
Carbonation reaction occurs between airborne CO2 and Ca (OH) 2 in Concrete.
→Causing softening of the concrete surface, causing concrete to be damaged.
The carbonation process starts from the concrete surface and spreads into the concrete.
→Reduce the alkali level in Concrete, activate the reinforcement corrosion process.
For works in or near the marine environment:
- Chloride corroding reinforcement in Concrete: Chloride ions in seawater will penetrate into
Concrete and corrode the reinforcement in Concrete.
- Sulfate attacking Concrete: Sulfate in combination with tricalcium aluminate C3A in cement form the ettringite crystals. This reaction increases the volume of Concrete, causing cracking of the Concrete structure.
→Therefore, there should be methods to protect Concrete.
4.Method of preserving concrete currently
Currently, on the market, the most common method for protecting Concrete works is to use paint or chemicals to cover the surface:
- Paints are inorganic or organic glues mixed with pigments and additives.
- The coating Paint is applied to the surface to create a protective film for the Concrete.
However, this method is ineffective, because some disadvantages are as follows:
- Inner water vapor can not escape, causing the Concrete surface is not exposed to the natural environment (not breathable).
- The layer of water vapor on the surface forms a favorable environment for the growth of moss and mold and is easy to be stained, causing damage to the surface of Concrete.
- Lose the aesthetic of Concrete constructions.
- Appear the aging of surface, discoloration and reduction of life expectancy for the works.
- Influence on structure of steel internal.