Betonijulkisivujen ja parvekkeiden säilyvyys suomalaisissa suunnitteluohjeissa

Kirjoittajat

• Jukka Lahdensivu

Abstrakti

Durability of concrete facades and balconies in Finnish design guidelines

Design guidelines for concrete structures have been published in Finland since 1915. In the early decades of developing concrete technology the focus was on increasing compression strength and homogenizing concrete in every batch. Durability properties of concrete exposed to climatic stress were only considered in the 1970s when limitations to the temperatures of heat treatment of fresh concrete were set. Frost resistance was only considered as late as 1976 when guidelines for using air entrainment in concrete mix were established. Regulations for thicker cover depths for reinforcement were introduced at the same time. Increasing compression strength of concrete has also increased its durability because higher strength concrete is usually tighter and more durable against weather stress.

Concrete codes and other national design guidelines have influenced the durability properties of concrete facades and balconies with a relatively long delay. In practice, concrete panels manufactured since the 1990s are mostly in accordance with the specifications of concrete codes and design guidelines published more than decade earlier.

The aim of establishing concrete codes and other design guidelines has been to continuously improve the quality of concrete structures. The lifespan of structures was not considered until 2004, when the basic level for service life was set for 50 years for facades and 100 years for concrete frames. There are no lifespan regulations in earlier codes or guidelines.