硫酸盐环境下CFRP加固顺序对混凝土梁界面黏结性能影响

提出了先粘贴CFRP后硫酸盐腐蚀以及先硫酸盐腐蚀后粘贴CFRP两种加固顺序,开展了64块CFRP-混凝土试件的双剪试验,分析了CFRP粘贴顺序、粘贴长度、粘贴宽度对混凝土界面破坏模态、抗压强度、剥离荷载、黏结强度、界面能、黏结应力-滑移曲线的影响,并基于硫酸盐环境影响系数建立了CFRP-混凝土界面黏结强度模型。试验结果表明,硫酸盐环境下,环氧树脂胶体能较好的保护混凝土黏结区域;随着硫酸盐腐蚀时间的延长,界面的剥离荷载、黏结强度均呈下降趋势,腐蚀至123 d时,下降最为严重,而对于界面断裂能,腐蚀至123 d时,下降幅度反而降低;CFRP黏结长度为65 mm下的界面黏结强度最大,随着黏结长度的增加,CFRP-混凝土界面的黏结性能逐渐降低;硫酸盐环境影响系数的提出可为恶劣环境的分类提供科学依据。

Influence of CFRP Paste Sequence on Bond Performance of Concrete Beam Interface under Sulfate Environment

Two kinds of reinforcement sequence, CFRP first, then sulfate corrosion, and sulfate first, then CFRP, were put forward, and the double shear tests of 64 CFRP-concrete specimens were carried out, and the effects of CFRP paste sequence, bond length and width of bond on the failure mode, compressive strength, failure load, bond strength, fracture energy, bond stress-slip curve were analyzed, the bond strength model of CFRP-concrete interface was established based on the environmental impact coefficient of sulfate. The results show that the sulfate environment, epoxide resin can better protect concrete bond area. With the prolongation of sulfate corrosion time, failure load and compressive strength of the interface decrease, and when corrosion time is 123 days, the decline is the most serious, but for the interfacial fracture energy, when corrosion time is 123 days, the decrease range is reduced. Interfacial bond strength is maximum when CFRP bond length is 65 mm, with the bond length increases, the bond performance of interface between CFRP and concrete gradually reduces. The sulfate environment influential coefficient can provide scientific basis for the classification of harsh environment.