Crumbling Barn Floors

Ever year, a number of serious accidents are caused by the collapse of concrete structures in the agriculture industry. A farmer in the County of Sør-Trøndelag, for example, got a nasty shock when the floor of his barn gave way without warning, and 20 cows fell into the manure cellar. One of the causes of accidents of this sort is that concrete cannot withstand the gases given off by wet cow manure. The first phase of the “Concrete in Agriculture” project, which surveyed the situation, has just come to an end; field studies were carried out in the Counties of Møre og Romsdal and Sør-Trøndelag.

The survey of 281 manure cellars showed that the need for repairs is much greater than had previously been realized. In terms of the country as a whole, rehabilitation would probably cost some NOK 5 billion. This figure covers damage that can already be seen, but more damage will appear as the building mass grows older. Many barns urgently need repairs because of inadequate reinforcement, particularly between floors and walls. In several buildings, the concrete floor or their supports had completely disintegrated, often in combination with the appearance of rust in the reinforcement bars. This has led to barn floors collapsing and walls falling down.

Scientists are still not quite sure why this happens, but they theorize that the aggressive chemical environment of the manure cellar, combined with poor-quality materials, eat up the concrete. In the next phase of the project, scientists from NTNU, SINTEF and the Agricultural University of Norway will find out whether it is possible to develop a concrete capable of withstanding the aggressive environment of manure cellars. The Norwegian Agricultural Inspectorate, the Gjensidige and Storebrand insurance companies, the Norwegian Farmers’ Union, regional agricultural authorities and the concrete industry are all taking part in the project.

By Anne-Lise Aakervik