HIGH-TEMPERATURE COMPRESSIVE STRENGTH TESTING DEVICE

A device 1, 20 for determining the compressive strength of materials which are resistant to high temperature can be clamped in a pressure testing machine which has clamping jaws 6 tapered conically outwards for inserting a specimen 7, clamping sleeves 5, 25 which receive the clamping jaws 6 and a furnace 12 surrounding the clamping parts for heating the specimen, the clamping jaws 6 and the clamping sleeves 5, 25 being composed of graphite. The clamping jaws 5, 25 are inserted in back-up rings 10, 22a made of carbon-fibre-reinforced carbon, the back-up rings having a lower coefficient of thermal expansion than the clamping sleeves. The whole device 1, 20 is inserted in an evacuable chamber 13, which can also be filled with protective gas.