Bond strength evaluation between textiles reinforced mortar with carbon nanotubes and concrete substrate

Abstract The influence of using carbon nanotubes to improve bond strength between textiles reinforced mortar and concrete was investigated. Forty-two specimens were tested using double-shear test to evaluate the effect of various parameters such as CNTs addition, type of textile material, bond length and width, and number of TRM layers on the bond behavior. Two types of textile: carbon and basalt fibers were used. Various bond length and width including 50 mm, 100 mm, and 150 mm were considered. Three different percentages of CNTs; 0.05%, 0.1%, and 0.2% by weight of cement, were used. The effect of CNTs addition on the mechanical strength of cement mortar and pull-off strength of TRM were also investigated. Test results showed that adding small amount of CNTs enhanced the tensile and flexural strength of cement mortar, the pull-off strength of the TRM, and the ultimate bond load between the TRM and concrete substrate. The ultimate bond load was highly dependent on the amount of added CNTs, type of textile material, geometry of the bonded area, and number of TRM layers. The SEM images showed the role of the CNTs to enhance the adhesion at the fiber-matrix interface.

摘要 本研究探讨了利用碳纳米管（carbon nanotubes，CNTs）提升织物增强砂浆与混凝土之间粘结强度的影响。本次试验共制备42个试样，采用双剪切试验评估多项参数对粘结性能的作用，涉及CNTs掺量、织物材料类型、粘结长度与宽度以及织物增强砂浆（Textile Reinforced Mortar，TRM）层数。试验选用碳纤维与玄武岩纤维两类织物材料，设置的粘结长度与宽度涵盖50 mm、100 mm及150 mm三种规格，同时采用三种不同的CNTs掺量，分别为水泥质量的0.05%、0.1%与0.2%。此外，本研究还探究了CNTs掺加对水泥砂浆力学强度以及TRM拉拔强度的影响。试验结果表明，掺入少量CNTs可显著提升水泥砂浆的抗拉与抗弯强度、TRM的拉拔强度，以及TRM与混凝土基层之间的极限粘结荷载。极限粘结荷载受CNTs掺加量、织物材料类型、粘结区域几何尺寸以及TRM层数的影响显著。扫描电子显微镜（Scanning Electron Microscopy，SEM）图像揭示了CNTs在纤维-基体界面处强化粘结作用的机理。