荷载与冻融循环对CFRP高强混凝土界面黏结性能影响

Effect of Freeze Thaw Cycles and Sustained Loads on Interface Bond Properties of CFRP and High Strength Concrete

关键词:  碳纤维增强复合材料  高强混凝土  持续荷载  冻融循环  黏结耐久性

Key words:  carbon fiber reinforced polymer(CFRP)  high strength concrete  sustained load  freeze thaw cycle  bond durability

摘要:

通过双剪试验，研究了冻融循环和持续荷载共同作用下碳纤维增强复合材料（CFRP）高强混凝土界面的黏结性能.结果表明：冻融循环和持载作用均对CFRP高强混凝土的黏结性能产生了不利影响，冻融循环使其极限荷载和极限黏结滑移显著减小，持载则降低了其黏结刚度；冻融循环和持载的共同作用使界面黏结性能退化进一步加剧，而有效黏结长度增加.此外，界面的破坏形式由树脂与混凝土之间的黏结破坏转变为表层混凝土的剪切破坏，说明冻融循环和持载作用引起的混凝土劣化是导致界面黏结性能降低的主要原因.

Abstract:

The adhesion of CFRP(carbon fiber reinforced polymer) to high strength concrete subjected to different sustained loads and freeze thaw cycles was studied with double lab shear tests. The results indicate that each factor has adverse effects on the bond properties:freeze thaw cycles significantly decrease ultimate loads and ultimate slips, sustained loads reduce the stiffness. Their combination causes a further deterioration of bond properties and increases the effective bond length. In addition, failure mode turns into the shear failure of surface concrete, instead of the one between adhesive and concrete, illustrating that the degeneration of concrete caused by sustained loads and freeze thaw cycles is the major reason of the reduction of interface adhesion.