Influence of combined freeze-thaw cycles and seawater saturation on the flexure behavior of reinforced concrete beams

초록

The Arctic Circle presents the most severe conditions among cold regions. Concrete structures there are often vulnerable to chemical attacks, especially from freeze-thaw cycles and seawater exposure. Understanding the structural behavior of reinforced concrete structures under these conditions is crucial to improving their durability and performance throughout their service life. This study investigated the flexural behavior of reinforced concrete beams with varying compressive strengths subjected to the combined effects of freeze-thaw cycles and seawater saturation. Six beams were fabricated and subjected to flexural loads under varying temperature and exposure conditions. The results show that seawater saturation reduced the number of cracks and increased the cracking loads, particularly in beams fabricated with normal-strength concrete. Furthermore, the failure loads and flexural ductility of seawater-saturated beams were lower owing to the decrease in concrete strength. The cracking and ultimate loads of high-strength concrete were 56 % and 7 % higher, respectively, than those of normal-strength concrete beams. The freeze-thaw cycles also influenced the cracking patterns and behavior of the beams. High-strength concrete beams showed greater crack widths after reinforcement yielding following freeze-thaw cycles. These findings demonstrate that the effects of concrete strength and seawater exposure on beam performance under static loads are more pronounced when freeze-thaw cycles are involved.

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