Investigation of old Building Concrete(8. Two Primary School's Assembly Halls)

Two reinforced concrete assembly halls were investigated. They were forty two years old. One of them was located in the west coast and the other in the east coast of the Noto peninsula. In both cases，columns，beams and walls were severely damaged. Especially in columns， wide and long cracks were found along the reinforcing steels. Cover mortar and cover concrete were easily taken off. And reinforcing bars were corroded and swollen into charcoal state. The investigations revealed that the main cause of the damage was the salt attack on reinforced concrete in one case and the carbonation of the hydrated cement in the other. It is indicated that the life span of existing reinforced concrete building is to be re-evaluated. The durability of reinforced concrete is stil1 to be studied based on the compiled investigations of old buildings