氯盐干湿循环作用下嵌入式CFRP筋与混凝土界面粘结性能研究

EXPERIMENTAL STUDY ON BOND PERFORMANCE OF NSM CFRP BARS WITH CONCRETE UNDER CHLORIDE SOLUTION WET-DRY CYCLING ENVIRONMENT

海岛工程建设中,潮汐作用下的海水干湿循环是影响纤维增强复合材料(FRP)加固混凝土结构耐久性能的主要因素之一。针对碳纤维增强复合材料(CFRP)筋嵌入法加固混凝土结构,通过CFRP筋从混凝土块中的拔出试验研究高性能纤维增强水泥基复合材料(HPFRC)和环氧树脂胶作为加固粘结材料时,海水干湿交替循环作用下嵌入式CFRP筋与混凝土界面的粘结性能,并对其破坏模式、极限粘结承载力进行分析。结果表明:环氧树脂胶作为粘结材料时,随干湿交替循环次数的增加,极限粘结承载力略有下降;而HPFRC作为粘结材料时,干湿循环90 d内的极限粘结承载力得到持续增长,可以达到作为粘结材料时极限承载力的70.3%,因此HPFRC可以作为粘结材料应用于潮汐环境下的FRP筋嵌入法加固海工混凝土结构中。

In the island construction,the seawater dry-wet cycling under tidal action is one of the main factors affecting performance of NSM（ near-surface-mounted） FRP（ fiber-reinforced polymer） strengthened concrete structures. Thus,the present study is aimed at the durability of NSM CFRP bars reinforced concrete with two types of bonding materials,i. e.,high performance fiber-reinforced cementitious materials（ HPFRC） and epoxy resin,by pull-out test of CFRP bars from concrete blocks under the simulated seawater dry-wet cycling condition. The failure modes and load carrying capacity are then analyzed. The results show that the strengthening performance of the specimens with epoxy decreases slightly. But the strengthening performance of specimens with HPFRC increases steadily in the wet-dry cycles of 90 days,and the load carrying capacity can be improved to 70. 30% of that for specimens with epoxy resin. Therefore,HPFRC can be used as bonding materials in NSM FRP reinforced marine concrete structures under tidal environment.