Karbonatiseringen

Karbonatiseringen is a Swedish term referring to the process of carbonation in concrete. This phenomenon occurs when carbon dioxide from the atmosphere reacts with the calcium hydroxide present in hardened cement paste. This reaction forms calcium carbonate and water, effectively changing the chemical composition of the concrete. Over time, this process can lead to a decrease in the alkalinity of the concrete. The depth of carbonation depends on several factors, including the humidity, temperature, the permeability of the concrete, and the concentration of carbon dioxide in the surrounding environment. Higher humidity generally accelerates the process, while very dry or saturated conditions can slow it down. The presence of cracks or porous structures in the concrete can also increase the rate of carbonation by allowing easier penetration of carbon dioxide. A significant consequence of carbonation is the potential reduction in the passive protection of reinforcing steel. Steel is protected from corrosion by the high alkaline environment of concrete. As carbonation reduces this alkalinity, the steel can become susceptible to rust if moisture and oxygen are present, leading to expansion and cracking of the concrete. Therefore, understanding and monitoring karbonatiseringen is important for assessing the durability and service life of concrete structures.