Experimental study on the strain recovery of concrete after creep

Concrete recovers from creep strain when load is removed. The relationships between instantaneous strain recovery coefficients and stress levels are established based on the experimental data of concrete specimens that experienced creep and then recovered. The instantaneous strain recovery coefficients vary from 0.65 to 0.95 and decrease with increasing stress levels. The relationships between the stable recovery time of lag strain and stress levels are obtained using the experimental data. The stable recovery time of lag strain is extended with increasing stress levels when the stress level is below 0.65. Experimental results indicate that the final recovery value of lag strain is proportional to creep strain, and the ratio is about 11.4 %. Finally, the calculation model for the recovery value of lag strain and time is developed, which could be used for the reasonable calculation of the recovery value of lag strain.