通过电化学加速锈蚀、钢筋和UHTCC直接拉拔试验对不同锈蚀率(0,1%,2%,3%和5%)下钢筋与UHTCC的粘结性能进行了研究,并与同条件下的混凝土试件进行对比。通过直接拉拔实验得到不同锈蚀率时平均粘结应力与滑移量的关系,采用粘结滑移的连续模型进行拟合,模型值与实验值吻合较好。与混凝土试件锈蚀率超过2%后最大平均粘结应力迅速下降现象不同,UHTCC能充分发挥其对钢筋的约束作用,在锈蚀率小于3%范围内,最大平均粘结应力随锈蚀率增大线性增加,锈蚀率超过3%直到5%基本维持不变,保持较好的粘结性能。
Ultra high toughness cementitious composites (UHTCC), featured with its strain hardening char- acteristic and outstanding crack controlling under tensile conditions, could greatly enhance the durability of reinforced concrete structures and prolong the service life of infrastructures. By means of accelerated corro- sion test and direct pulling test, bond properties between corroded rebar with different corrosion ratio(0, 1%, 2%, 3% and 5%) and UHTCC were investigated, did the same for corroded rebar and ordinary concrete while other things being equal. The relationships between average bond stress and end slip with different corrosion ratio were presented. A constitutive model for bond slip relation between rebar and UHTCC was applied for simulating the test results, and fit well. The relationship between maximum average bond stress and corrosion ratio indicated that UHTCC could restrict the corrosion expansion. The maximum average bond stress of rebar and UHTCC increased linearly before corrosion ratio up to 3%, then remained constant till to 5%, while the maximum average bond stress between rebar and concrete decreased rapidly when the corrosion ratio exceeded 2%.