Cast Concrete Containing Crushed Brick - Investigation of a Case of Damage.

The very low, considerably scattered compressive strength of cast concrete walls - the aggregate of which consisted of broken birck - caused the short notice evacuation of two seven-story buildings in Berlin-Britz. The intent of these constructions was to get the highest possible thermal insulation of the external walls due to its no-fines concrete structure. It especially met with the economic necessities of the post-war period, for it allowed the quick erection of cheap apartments utilizing the brick rubble of German cities. In order to carry out a fundamental extensive investigation of the causes of damage as well as of material behavior and possibilities of restoration, wall elements were taken from the building and subjected to laboratory testing. The working load of the structural elements was derived from the compressive strength for a certain area of the building using a probabilisitc concept for the assessment of safety. This way the cast concrete walls of other buildings could be checked by using the ultrasonic test.