The concrete used for construction should be distinguished by its reliable durability - and this under various environmental conditions. If this is not the case, it can corrode and weaken the structure. Concrete carbonation is one type of corrosion. What is worth knowing about it?
What is concrete carbonation?
Concrete carbonation is a process that affects the outside of a structure made of concrete. It occurs gradually under the influence of carbon dioxide, which has a negative impact on the concrete structure. As a result of exposure to CO2 as the formation of CaCO3 commonly known as calcium carbonate.
Carbonation of concrete - effects
Calcium carbonate does not degrade the structure of the concrete, although it does alter its pH. Under the influence of CaCO3 drops below pH 9, so that the surface of the reinforcing steel begins a slow process of deterioration. As a result, it starts to become covered with rust, which over time leads to concrete failure. This, in turn, can cause the concrete lagging to flake off, so that the reinforcement is exposed.
Carbonation of lime - what is it?
As with concrete, this occurs during the chemical relationship between water and carbon dioxide. This results in the binding of lime. The effect of carbonatisation is therefore the hardening of this m1TP2Body, as is the case with the crystallisation of mortar, which loses water. In comparison, the process of carbonatisation is much slower. It is also worth noting that it usually only covers part of the mortar. In the case of deeper layers - the process can take years. It is also worth mentioning that carbonation affects lime coatings, including paints. On coatings that dry too quickly, so-called paint burning can be observed. This will cause the lime paint to rub off. On the other hand, if it dries too slowly - the coating will become glassy and lose its white colour.
Carbonation of cement - what is it?
Carbonation of cement is a process that occurs as a result of carbon dioxide and calcium hydroxide. The chemical reaction between them results in the formation of water molecules and calcium carbonate. The latter, as with concrete - lowers the pH level of the cement, which poses a serious threat to external screeds. In combination with acid rain, the carbonation of cement can end up corroding the reinforced concrete.
How to prevent carbonisation?
The carbonylation process mainly affects m1TP2Bodies that are susceptible to CO2. Therefore, an effective way to eliminate this problem is to purchase good quality products. According to the current construction law, every concrete has a specific carbonation class. In order to determine it, a concrete carbonation test is carried out, which involves spreading an indicator preparation on the concrete break. This can be done using the phenolphthalein test or the so-called Rainbow-Test. Preventing carbonation also involves providing the concrete with the right conditions during setting. To this end, lagging on the reinforcement is recommended to prevent the concrete from cracking.