Strain recovery model for concrete after compressive creep

The research objective of this study is to examine the strain recovery of concrete after compressive creep. First, the influences of concrete strength, load duration, and stress-strength ratio at loading time on the initial-recovery are investigated on 128 concrete prisms. The concrete strength, loading age, and load duration have no clear influence on the initial-recovery strain coefficient (the ratio of initial-recovery strain to initial strain) when the concrete age concrete is over 28 d and load duration is over 41 d, but the initial-recovery strain coefficient decreases as the stress-strength ratio at loading time increases. Moreover, the effects of loading age, load duration, and concrete strength on creep-recovery are investigated by examining data from tests and references. The basic creep-recovery model is obtained by fitting the creep-recovery experimental data from 28 concrete prisms. Then, a multi-coefficient creep-recovery model for concrete that considers the influence of creep, loading age, load duration, and concrete strength is proposed. Finally, the proposed creep-recovery model is verified with reference data, with better performance than the existing creep-recovery models.