Creep of high strength concrete at elevated temperatures

The creep behaviour of the HTR high strength concrete was studied in the test laboratories of ETH Lausanne, TU Braunschweig and Univ. of Cassel. Unsealed and sealed concrete specimens were tested up to 120 deg. whereby different test procedures and test methods were applied. Important influences on the high temperature creep are the test temperature, the load level during heating up, the process of drying during heating and the type of sealing during the heat exposure. Specimens tested under saturated vapour atmosphere (autoclave tests) indicated the largest creep strains. The creep of drying specimens at 80 or 120 deg. C turned out to be very low after the drying process is completed. Wet specimens sealed with polymer resin and metal foils indicated less creep than those specimens which were tested in an autoclave at high temperatures. (author)