Comparison between creep in tension and compression at early age high performance concrete

Viscoelastic behaviour of early age concrete in tension plays a significant role in the stress development, and thereby also for the crack sensitivity. Distinguish between early age tensile and compressive creep might be very important in relation with determination of self-induced stresses. In the present investigation a comprehensive experimental study is carried out involving construction of new creep test equipment for tensile creep tests. Parallel creep tests are conducted under tension and compression to characterize creep development at early age high performance concrete (HPC). It was found that the instantaneous deformation under tension is smaller than under compression, and that the corresponding creep curves are also different. Tensile creep is found to be lower initially, but an almost linear rate is soon established which is much higher than in compression. The consequence is grater creep magnitude and thus greater creep coefficient in tension than in compression.