Reijo Yla-Mattila Technical Research Centre of Finland


In a Finnish winter there are many freezing and thawing cycles with temperatures at times as low as -30°C. Bricks, mortars and renderings may fail. Chimneys may corrode or fail in frost due to condensation of the flue gases. Temperature changes in the walls of an experimental building showed significant differences in temperatures and numbers of freezing cycles experienced in accordance with the surface radiation characteristics of the four different bricks used. Laboratory freezing tests on individual bricks do not simulate natural conditions and a method of freezing from one side to test both bricks and mortar is described.