Non-linear creep effects in concrete under uniaxial compression

The non-linear creep behaviour of plain concrete subjected to high compressive stress levels is investigated in this paper. An experimental creep study is performed, which includes testing of four series of concrete cylinders under sustained uniaxial compressive stress of 30%, 50%, 60% and 70% of the compressive strength. The four tests series were commenced at the same age of concrete and were carried out for a period of 194 d under constant controlled environmental conditions. Creep recovery for a period of 63 d was allowed under the same environmental conditions after unloading, and the influence of creep on the compressive strength was also tested. Simple analytical models that exist in the literature are compared with the experimental creep results.