Concrete is one of the most popular construction materials. Concrete is used since antiquity. Its versatility makes this material to be used in many residential, commercial, industrial and military construction projects.
Concrete is a very interesting material. Its composition is Portland cement, aggregate (sand or rock) and water.
Concrete behaves very well to compression but weak in tensile strength. It seems paradoxical, but concrete is a relatively fragile material. In time, concrete will erode and tear. Knowing how to prevent concrete degradation is critical but first, you need to know what is causing its degradation.
Concrete durability is due to the water–cement ratio. A perfect ratio makes a durable and strong concrete. However, concrete is a porous construction material and it is susceptible to corrosion if it is in contact with chemical agents.
Concrete Chemical Degradation
There are three forms of chemical degradation:
1) Corrosion: Different chemical agents in contact with the concrete surface can penetrate and spread inside, due to the concrete porosity, and affect the reinforcements used. Usually, the reinforcements are re-bar, which can be corroded. Corrosion will spread and weaken the concrete strength.
Solution: Adding fibers in the concrete composition can diminish the corrosion, the rust and will remove the concrete tends to crack.
2) The effect of acids: Chemicals and especial acids can dissolve the cement from the concrete composition leading to concrete degradation.
Solution: Adding concrete densifiers (hardeners) will prevent the acids to penetrate inside the concrete.
3) Concrete efflorescence: This is one of the most common problems for concrete. The water will dissolve the salts from the concrete chemical composition and will bring these salts to the surface as a white powder.
Solution: It is the same solution as for acids. The concrete hardeners will prevent also, the water to penetrate and dissolve the salts.
Concrete Physical Degradation
In fact, physical deterioration of the concrete is also due to its porosity. In cold season, water penetrates inside of the concrete and freeze. When freezing water expands, and can make concrete to crack and peel.
Solution: A simply solution is to add air entraining agents in the concrete mixing process. That will create microscopic air bubbles in the concrete and the frozen water will expand into the air bubbles instead of the concrete material. However, to prevent a further infiltration adding concrete hardener is recommended.