Durability properties and deterioration of concrete balconies of inadequate frost resistance

Abstract

The most common degradation mechanism causing need to repair concrete balconies in Finland is corrosion of reinforcement due to carbonation and small cover depth of reinforcement together with inadequate frost resistance of concrete. During the last almost 20 years repair of concrete facades and balconies has been very active and has produced a great deal of information about the actual condition of repaired buildings. The resulting extensive and growing database can be used, for example, to estimate future repair needs of concrete structures. Data have been gathered from 947 buildings including the distribution of different kinds of damage modes and the interdependence between the damage and other factors. The 1943 protective pore ratio (pr) tests of this database show that 69% of the side wall elements of Finnish balconies are not frost resistant, pr < 0.10. The same is true for 57% of the floor slabs and 47% of the parapets. Similar phenomena related to frost damage in concrete are revealed by thin-sec...