持载作用下CFRP-高强混凝土界面的抗冻性能
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摘要
目的研究持载状态下CFRP-高强混凝土界面的抗冻性能.方法利用自行设计的加载装置将试件施加持续荷载后进行冻融循环试验,通过双面剪切试验对粘结界面的抗冻性能进行研究.结果粘结面受到冻融循环作用后,试件的承载能力显著降低,在较多的冻融循环次数下,冻融时施加持续荷载对试件的极限承载力有更加不利的影响;持载冻融的试件发生剥离时的荷载相对最低,界面剥离后,荷载增长幅度最小;第一测点处的最大应变值有明显的降低,而是否持载对其没有特别的影响;剪应力峰值下降趋势明显.结论冻融时施加持续荷载将会对CFRP-高强混凝土界面造成额外的损伤,导致界面的弹性模量降低,承载能力下降.
Based on double shear test,the freeze-thaw resistance behavior of bonded joints between CFRP and high strength concrete under sustained load is studied.The results show that after bond interface between CFRP and high strength concrete are subjected to freeze-thaw cycles,the carrying capacity of specimen decreases significantly.And there is a more negative impact on the carrying capacity under more freeze-thaw cycles for specimens imposed sustained load.When the specimens imposed sustained load under the freeze-thaw condition,debonding load is lowest relatively and the growth increment of load is lowest after bond interface debonded.The maximum of strain in the first measure point drops obviously,and it has no particular effect on imposed load under the freeze-thaw condition and downtrend of peak value of shear stress is significantly decreasing.It can be concluded that extra damages to bonded interface can be caused by sustained load,which leads to the decrease of the elastic modulus and the drop of the load carrying capacity.Finally,the influence mechanism of freeze-thaw cycle on behavior of bonded joints under sustained load is analyzed.
Based on double shear test,the freeze-thaw resistance behavior of bonded joints between CFRP and high strength concrete under sustained load is studied.The results show that after bond interface between CFRP and high strength concrete are subjected to freeze-thaw cycles,the carrying capacity of specimen decreases significantly.And there is a more negative impact on the carrying capacity under more freeze-thaw cycles for specimens imposed sustained load.When the specimens imposed sustained load under the freeze-thaw condition,debonding load is lowest relatively and the growth increment of load is lowest after bond interface debonded.The maximum of strain in the first measure point drops obviously,and it has no particular effect on imposed load under the freeze-thaw condition and downtrend of peak value of shear stress is significantly decreasing.It can be concluded that extra damages to bonded interface can be caused by sustained load,which leads to the decrease of the elastic modulus and the drop of the load carrying capacity.Finally,the influence mechanism of freeze-thaw cycle on behavior of bonded joints under sustained load is analyzed.
引文
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[7]胡安妮.荷载和恶劣环境下增强结构耐久性研究[D].大连:大连理工大学土木水利学院,2003.
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[10]Taljsten B.Defining anchor lengths of steel andCFRP plates bonded to concrete.[J]InternationalJournal of Adhesion and Adhesives,1997,17(4):319-327.
[2]王苏岩,韩克双,曲秀华.CFRP加固高强混凝土柱改善延性的试验研究[J].世界地震工程,2005,21(3):7-10.
[3]王苏岩,杨玫.碳纤维布加固高强钢筋混凝土梁抗弯性能试验研究[J].建筑科学,2006,22(5):34-38.
[4]王苏岩,刘磊.CFRP约束高强混凝土柱长期性能研究[J].沈阳建筑大学学报:自然科学版,2007,23(1):42-46.
[5]中国建筑科学研究院建筑材料研究所.GBJ82-85普通混凝土长期性能和耐久性能试验方法[S].北京:中国标准出版社,1986.
[6]任慧韬.纤维增强复合材料加固混凝土结构基本力学性能和长期受力性能研究[D].大连:大连理工大学土木水利学院,2003.
[7]胡安妮.荷载和恶劣环境下增强结构耐久性研究[D].大连:大连理工大学土木水利学院,2003.
[8]Kolluru V S,Michel G,Ali-Ahmad M.Impact offreeze-thaw degradation on FRP-concrete inter-face fracture[J].Advances in Construction Materi-als,2007,5:419-426.
[9]Kolluru V S,Ali-Ahmad M,Michel G.Freeze-thaw degradation of FRP-concrete interface:Impacton cohesive fracture response[J].Engineering Frac-ture Mechanics,2008,75(13):3924-3940.
[10]Taljsten B.Defining anchor lengths of steel andCFRP plates bonded to concrete.[J]InternationalJournal of Adhesion and Adhesives,1997,17(4):319-327.
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