Flexural behavior of RC beams strengthened with CFRP sheets under low-temperature exposure

초록

With the increasing number of reinforced concrete (RC) structures exposed to low-temperature environments due to climate change and development in polar regions, understanding their structural behavior under such conditions has become critical. RC structures in cold regions also experience severe environmental deterioration, highlighting the anticipated need for their repair and strengthening. This study experimentally investigates the flexural behavior of RC beams strengthened with carbon fiber reinforced polymer (CFRP) sheets under low temperatures. A total of twelve RC beams were fabricated, including six strengthened with CFRP, and tested at 20 degrees C, -20 degrees C, and -60 degrees C to evaluate load capacity, deflection, strain distribution, and crack development. The results revealed that unstrengthened beams showed improved strength and stiffness at lower temperatures due to the increased mechanical properties of concrete and reinforcing bar, whereas CFRP-strengthened beams exhibited limited strength gains but a marked reduction in ductility caused by the degradation of CFRP tensile performance at low temperatures. These findings suggest that, to prevent the reduction in ductility observed in CFRP-strengthened RC beams at low temperatures, it is essential to achieve a proper balance between tensile and compressive forces by considering both the enhancement of concrete strength and the degradation of CFRP performance.

키워드