Kim Hyeong-Yeol, You Young-Jun, Ryu Gum-Sung
Structural Engineering Department, Korea Institute of Civil Engineering and Building Technology (KICT), Goyang-Si 10223, Korea.
Materials (Basel). 2022 Jun 24;15(13):4469. doi: 10.3390/ma15134469.
The repair of underwater concrete structures is usually difficult work, requiring specialized materials and installation systems. This paper presents a carbon-textile-reinforced concrete (TRC) grouting system for underwater repair of concrete structures. One multi-purpose grout and two types of underwater grouts were considered in this study, and the bond performance between the substrate and grout was evaluated by a bi-surface shear test with cubic specimens. The bond strength of the repair material is greatly affected by the casting and curing conditions. When the multi-purpose grout is used, the average bond strength of the specimens cast and cured in dry conditions is only 22% of the specimens cast and cured in underwater conditions. On the other hand, the maximum difference in bond strength is, at most, 15.8% when non-dispersive, anti-washout grouts are used. Two types of installation methods were proposed and four full-scale RC slab specimens were repaired with the TRC grouting method, two for each installation method. Regardless of the installation method, the load levels that causes concrete cracking, steel yield, and the failure of specimens repaired with the TRC grouting system are at least 37.5%, 16.6%, and 21.7% greater than those of the unrepaired specimen, respectively. The test results further indicate that the influence of the grouting materials on the ultimate load-carrying capacity of the specimens repaired with the TRC grouting system is insignificant, and the maximum difference is, at most, 4%.
水下混凝土结构的修复通常是一项艰巨的工作，需要特殊的材料和安装系统。本文提出了一种用于混凝土结构水下修复的碳纤维织物增强混凝土（TRC）灌浆系统。本研究考虑了一种多功能灌浆料和两种水下灌浆料，并通过立方体试件的双面剪切试验评估了基层与灌浆料之间的粘结性能。修复材料的粘结强度受浇筑和养护条件的影响很大。当使用多功能灌浆料时，在干燥条件下浇筑和养护的试件的平均粘结强度仅为在水下条件下浇筑和养护的试件的22%。另一方面，当使用非分散性抗冲刷灌浆料时，粘结强度的最大差异至多为15.8%。提出了两种安装方法，并使用TRC灌浆法修复了四个全尺寸钢筋混凝土板试件，每种安装方法两个。无论采用哪种安装方法，导致混凝土开裂、钢筋屈服以及用TRC灌浆系统修复的试件破坏的荷载水平分别比未修复试件至少高37.5%、16.6%和21.7%。试验结果进一步表明，灌浆材料对用TRC灌浆系统修复的试件的极限承载能力的影响不显著，最大差异至多为4%。
