Through a long time test for creep of 9 PC (plain concrete) and RC cylinders, obtained the long-term creep rule of PC and RC cylinders, the results show that the different loading ages of PC have a greater influence on the creep coefficient, the larger loading age of concrete cylinders, the smaller of concrete creep coefficient. The experiment indicates that the measured creep rule of creep coefficient is basically the same under different loading ages with the same reinforcement ratio of concrete cylinders, the loading age have smaller influence on long-term creep of reinforced concrete cylinders. Based on the measured long-term rule of concrete creep, using the least square method to nonlinear fitting of experimental data, obtained the final value of creep coefficient of the PC under different loading ages, compared the applicability of loading age correction coefficient in the China Institute of building model and CEB-FIP (1990) model for low intensity concrete (≤C40), the results show that the predicted results of loading age correction coefficient in the China Institute of building model are agree well with the measured values, and calculated values of loading age correction coefficient in CEB-FIP (1990) model is large, for low strong concrete (≤C40), the prediction values of loading age correction coefficient in the China Institute of building model should be adopted to linear interpolation.
Nondestructive and destructive evaluation of FRP composite wrapped concrete cylinders with embedded debonds