湿/热条件下的CFRP筋粘结型锚具性能研究

Performance of Bonded Anchorage for CFRP Tendons Affected by Temperature or Moisture

为探索湿度和温度对碳纤维增强复合材料(Carbon fiber reinforced polymer,CFRP)筋粘结型锚具锚固性能的影响,对23℃干燥、23℃盐溶液及50℃盐溶液三种不同工况及不同浸泡时间下锚固系统的锚固性能进行了试验研究。制作四组共12个粘结型锚具试件,分析了不同环境条件下锚固系统吸水率、极限承载力、界面平均抗剪强度以及相对滑移的变化规律和界面损伤发展规律。在此基础上,建立了考虑湿度和温度影响的粘结型锚具极限承载力预测模型。分析结果表明,随着温度的升高或浸泡时间的延长,CFRP筋粘结型锚具极限承载力和界面平均抗剪强度均降低,锚固系统的延性和界面性能下降;温度对锚固系统损伤发展的影响较为显著;锚固系统在不同温度盐溶液中的吸水行为符合Fick第二定律;基于吸水规律提出的CFRP筋粘结型锚具极限承载力的预测模型与试验结果基本一致。

In order to investigate the effect of temperature and moisture conditions on the anchoring performance of the bonded anchorage for CFRP(Carbon Fiber Reinforced Polymer)tendons,tensile tests were carried out on the anchoring system with different moisture-conditioning(i.e.,dry state at 23℃,salt solution immersion at 23℃and salt solution immersion at 50℃)and different immersion durations.Twelve pre-conditioned bonded anchorages were tested,and their water absorption,ultimate tensile capacity,average interfacial shear strength,system slip and the damage development at the tendon/bonding medium interface were analyzed.With that,a prediction model for the ultimate tensile capacity of the bonded anchorage was established,accounting for the influence of temperature and moisture conditions.The results show that the ultimate tensile capacity and the interfacial shear strength of the bonded anchorage decrease with respect to the temperature and immersion duration.The ductility and interfacial performance of anchoring system are reduced with respect to hygrothermal conditions.The temperature is especially significant for the damage development in the anchor zone.The water absorption of the anchoring system under different temperatures follows Fick’s second law.And the proposed prediction model is in line with the experimental results substantially.