CFRPストランドの耐久性評価

抄録

In order to clarify the long-term durability of CFRP strands, tensile and fatigue tests at room and elevated temperatures were conducted. Firstly, tensile tests were performed under several temperature conditions from 23 to 250 ℃. The results showed that ultimate tensile strength of CFRP strands are dependent on temperature and superior to conventional steel materials. Secondly, fatigue properties at room temperature were examined and plotted on Haigh diagram. It is observed that CFRP strands have higher fatigue resistance than conventional steel wire rope used in prestressed concrete. In addition, a new data processing method was proposed to evaluate fatigue damage in CFRP strands. In this method, the phase angle between stress and strain is a significant factor that indicates damage in composites. It was shown that the fatigue mode changes around 10,000 cycles and the rapture is likely to occur before phase differences reach at the maximum value. Lastly, fatigue tests at 200 ℃ were conducted. The results showed that CFRP strands become sensitive to mean stress at elevated temperature.