Poikkipintaläpäisevyyden

Poikkipintaläpäisy (PAL) is a term used in Finnish to describe a type of structural failure in buildings, specifically in concrete structures. It refers to the cracking of the concrete cover due to the expansion of reinforcement bars, which are typically made of steel or high-strength steel. This phenomenon is caused by the corrosion of the reinforcement bars, leading to the expansion of the rusted steel, which in turn causes the concrete cover to crack.

The term "poikkipintaläpäisy" translates to "transverse surface cracking" in English. The cracking is typically observed on the surface of the concrete, perpendicular to the direction of the reinforcement bars. This type of failure is particularly problematic because it can lead to further deterioration of the structure, including the spalling of concrete and the exposure of reinforcement bars, which can then corrode more rapidly.

The causes of poikkipintaläpäisy are multifaceted and can include inadequate concrete cover, poor quality concrete, insufficient reinforcement, and environmental factors such as moisture and chlorides. Proper design, construction, and maintenance practices are crucial in preventing this type of failure. Regular inspections, timely repairs, and the use of protective measures such as cathodic protection can help mitigate the risk of poikkipintaläpäisy.

In summary, poikkipintaläpäisy is a significant concern in the field of structural engineering, particularly in concrete structures. Understanding the causes and effects of this failure mode is essential for ensuring the safety and longevity of buildings.