摘要
本文研究了海水浸泡环境对BFRP(Basalt Fiber Reinforced Polymer)筋与混凝土黏结性能的影响,测试了不同温度(25℃,40℃和55℃)下极限黏结强度随浸泡龄期的变化规律。结合加速腐蚀理论,并考虑环境温度和湿度的影响,对极限黏结强度随服役年限的变化规律进行了预测。参考既有文献中的97个BFRP筋黏结强度试验数据,推导了BFRP筋短期黏结强度计算公式。依据本文理论预测得出的50年设计使用年限下的黏结强度损伤因子,推导了不同环境湿度类别下的锚固长度计算公式。试验结果表明:25℃,40℃和55℃海水浸泡60天后,极限黏结强度分别降低了5.8%、9.1%和13.0%。预测结果表明,在南海年平均温度下,服役50年后,室内环境、一般室外环境和潮湿海洋环境类别下的黏结强度损伤因子分别为0.19、0.32和0.51。本文提出的基本锚固长度设计方法可为相关规范条款的制定提供依据。
In this paper,the effects of seawater immersion on the bond performance between BFRP( Basalt Fiber Reinforced Polymer) bar and concrete were investigated. The variations of ultimate bond strengths with immersion time at various temperatures( 25℃,40℃ and 55℃) were tested. In combination with the theory of accelerated corrosion,the degradation law of ultimate bond strength with service year considering the influence of environment temperature and humidity was predicted. In addition,the formula for the short-term bond strength between BFRP bar and concrete was derived from the data of 97 BFRP bar bond tests collected from literatures. With the bond damage factors for a design service life of 50 years predicted in this study,the calculation formulas for the basic anchorage length of BFRP bar with concrete at different environmental humidity categories were obtained. Test results showed that the ultimate bond strength was reduced by 5. 8%,9. 1% and 13. 0% after being immersed in 25℃,40℃ and 55℃ seawater for 60 days,respectively. The predicted bond damage factors for indoor environment,normal outdoor environment and humid ocean environment were 0. 19,0. 32 and 0. 51,respectively,after servicing 50 years at the annual average temperature of the South China Sea area. The proposed design method for the basic anchorage length of BFRP bar is reasonable and could be adopted by relevant specifications.
引文
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