TENSILE CREEP OF YOUNG HIGH PERFORMANCE CONCRETE

Abstract This paper concerns time dependent deformations in young high performance concrete (HPC). New experimental equipment has been developed to measure creep in tension. One-dimensional creep tests on cylindrical specimen are carried out in both tension and compression for different times of application of load, and the different test equipment used are described. So far results indicate that the total stress dependent deformation per unit stress in tension is considerably lower than the corresponding deformation in compression after a few hours of loading. This observation is of course important for practice where the creep properties measured in compressive experiments are used in analyses where the tensile creep phenomena occur. Note that total deformations as defined here are compensated for the autogenous shrinkage of unloaded dummy specimens. Results of stress rig tests are also analysed and presented. The stress rig is constructed to measure the stress generation in hardening concrete and is used for validation of material models and calculation methods. On the basis of these results, creep model is modified, and thermal transitional creep is taken into account. Keyword: High performance concrete, young concrete, tensile creep, compressive creep, basic creep, experimental tests and material model