Fan Jingchong, Wu Lili, Zhang Bo
School of Mechanics & Civil Engineering, China University of Mining and Technology, Beijing 100083, China.
State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China.
Materials (Basel). 2021 Feb 24;14(5):1057. doi: 10.3390/ma14051057.
The bonding surface structure generated by the repair of concrete structures has been paid more attention as a weak point. The effects of old concrete age, interface roughness, and freeze-thawing (F-T) attack on adhesive interface are comprehensively investigated. In this study, six kinds of interface roughness and five different old concrete age are designed. The interfacial bonding property is mainly evaluated by splitting tensile strength (). Fractal analysis was used to characterize the interface roughness using laser scanning data. In general, the increased with the increasing value of interface fractal dimension. The relationship between and fractal dimension value was further analyzed, considering the old concrete ages and the F-T cycles. The results show that the effect of roughness on the bonding property of new-to-old concrete is more significant than the age of old concrete, and the influence of the F-T cycles on the bonding surface is mainly reflected in the initial stage of the F-T deterioration process. The relative dynamic elasticity modulus decreased obviously under F-T cycles, especially for the specimens with low interface roughness. In combination with the results of two non-destructive methods (ultrasonic non-destructive test and relative dynamic elastic modulus test), the larger roughness and the smaller age of old concrete can improve the bond performance.
混凝土结构修复产生的粘结面结构作为薄弱环节受到了更多关注。综合研究了旧混凝土龄期、界面粗糙度和冻融（F-T）作用对粘结界面的影响。本研究设计了六种界面粗糙度和五种不同的旧混凝土龄期。界面粘结性能主要通过劈裂抗拉强度（）来评估。利用激光扫描数据通过分形分析来表征界面粗糙度。一般来说，随着界面分形维数值的增加而增大。考虑旧混凝土龄期和冻融循环次数，进一步分析了与分形维数值之间的关系。结果表明，粗糙度对新旧混凝土粘结性能的影响比旧混凝土龄期更为显著，冻融循环次数对粘结面的影响主要体现在冻融劣化过程的初期。在冻融循环作用下，相对动弹模量明显降低，尤其是界面粗糙度较低的试件。结合两种无损检测方法（超声无损检测和相对动弹模量试验）的结果，较大的粗糙度和较小的旧混凝土龄期可以提高粘结性能。
