Degradation of RC short beams under monotonic and repeated loads after cryogenic freeze-thaw cycles

ABSTRACT

To investigate the effects of cryogenic freeze-thaw cycles and repeated loading on the bearing capacity and deformation properties of reinforced concrete (RC) short beams, RC short beams with different reinforcement ratios were subjected to Minus 160°C cryogenic freeze-thaw cycles. Subsequently, a four-point bending tests were carried out under monotonic and repeated loading with the aim of exploring the performance characteristics of the test beams, such as failure mode, load‐deflection response, and ductility. Experimental results showed that the failure mode of RC short beams changed from ductile bending to brittle shear failure after cryogenic freeze-thaw cycles. Additionally, the load-carrying capacity, deformation properties and energy dissipation performance exhibited a significant degradation trend. There is decreasing trend for the ductility and ultimate bearing capacity of beams with the increase in freeze-thaw cycles, and the decrease degree was most obvious in the first three cycles. Moreover, compared with monotonic loading, the ductility index of normal temperature beam and freeze-thaw cycle short beam decreased more significantly under repeated loading, and the bearing capacity decreases more obviously under the last stage of multi-level loading and unloading cycles.

KEYWORDS:

• Cryogenic freeze-thaw cycles
• RC short beam
• repeated loads
• displacement ductility index
• energy ductility index
• energy dissipation capacity

Acknowledgments

This research was financially supported by Innovation Demonstration Base of Ecological Environment Geotechnical and Ecological Restoration of Rivers and Lakes (NO. 2020EJB004), National Natural Science Foundation of China (No.51508171), Natural Science Foundation of Hubei Province (No. 2020CFB860). The author would like to express his gratitude to their support to current research.

Disclosure statement

No potential conflict of interest was reported by the author(s).