超高韧性水泥基复合材料与锈蚀钢筋的梁式黏结试验研究

采用超高韧性水泥基复合材料(UHTCC)能够有效提升水工结构构件的抗氯盐侵蚀能力。然而,在长期氯盐环境侵蚀作用下,结构内部钢筋仍然可能遭受一定程度锈蚀,进而可能影响钢筋与基体材料的黏结性能。本文通过梁式界面黏结试验,对比研究锈蚀对钢筋与UHTCC、混凝土间界面黏结性能的影响。试验结果表明,与混凝土对比试件不同,UHTCC试件均呈现出延性的拔出破坏模式,以及完整的黏结滑移全曲线。在试验的锈蚀范围内,UHTCC试件并未发生锈胀开裂,而且UHTCC中的钢筋锈蚀较混凝土中更为均匀。UHTCC试件的黏结强度随锈蚀率先增大后降低,在14%锈蚀范围内黏结强度基本没有下降,锈蚀率约16%时强度仅下降5%。在16%锈蚀范围内,UHTCC试件的黏结韧性下降仅为5%。

Experimental study on bond behavior between UHTCC and corroded reinforcement using beam members

The use of ultra-high toughness cementitious composite (UHTCC) can improve the corrosion re-sistance of hydraulic structures effectively. However, the rebar in structural members may be subjected to corrosion to a certain extent under long-term chloride environment attack, possibly resulting in deteriorated bond performance of UHTCC and rebar. In the present paper, the effect of corrosion on bond behavior of UHTCC and rebar is investigated through bond tests using beam members. The experimental results indicat-ed that compared with concrete specimens, UHTCC specimens all presented ductile pull-out failure mode and full bond-slip curves. UHTCC samples all had no corrosion cracks in the range of corrosion level ob-tained in this test, and the rebar corrosion was relatively uniform. The bond strength of UHTCC specimens first increased and then decreased with increasing corrosion ratio. In detail, bond strength scarcely reduced at corrosion ratio below about 14%, and decreased by 5% at about 16% corrosion ratio. Meanwhile, the bond toughness merely reduced by about 5% within tested corrosion level of 16%.