Study on the long term durability of continuous fiber reinforcement and sheet reinforcement

利用室外暴露10 ~ 20年的试件，研究了连续纤维增强材料和片材增强材料的长期耐久性。两种CFRP索和两种AFRP索暴露17年后的松弛率结果约为20%。即使在最大载荷为强度的0.8倍的情况下，也没有观察到初始载荷的显著影响。回收的电缆试样也表现出几乎相同的机械性能的初始。两种类型的CFRP片材试样从10年的暴露恢复显示拉伸性能没有显着的变化，但观察到的面内剪切性能略有下降（约80%的强度和约60%的模量）。该结果表明，纤维本身具有良好的耐久性，但纤维和树脂之间的界面在某些情况下显示出轻微的劣化。

Long term durability of the continuous fiber reinforcement materials & sheet reinforcement materials was studied using specimens recovered from outdoor exposure tests for ten to twenty years. The results of the relaxation ratio after 17 years exposure were about 20% for two CFRP cables and two AFRP cables. No remarkable influence of the initial load was observed even the maximum case was 0.8 of the strength. The recovered cable specimens also showed almost same mechanical properties as the initial. Two types of CFRP sheet specimens recovered from ten years exposure showed no remarkable changes in tensile properties, however slight reduction of in-plane shear properties was observed (about 80% for strength and about 60 % for modulus). This result suggests that the fiber itself has a good durability however the interface between fiber and resin shows slight deterioration in some cases.