Abstract

Concrete is a building material widely used in construction due to its excellent mechanical properties such as compressive strength and bond strength with steel reinforcement. Strength and durability are the key factors that need to be satisfied in the design of reinforced concrete structures. The objective of this paper is to improve the bond strength and corrosion resistance of concrete by using supplementary nano cementitious materials such as Nano Metakaolin (NMK) and Nano Silica Fume (NSF). The addition of nano cementitious materials will help in enhancing the mechanical properties of concrete by improving the micro-structure. Effective bond between concrete and reinforcing steel ensures the load transformation among structural elements. The specimens are exposed to either chloride-induced acceleration-based corrosion test or chloride-induced immersion-based corrosion test. Investigations were conducted to evaluate the compressive strength, bond strength and corrosion resistance of concrete. Specimens with corrosion inhibitor/anti corrosive coating exhibited poor bond strength when compared to concrete with nano metakaolin and nano silica fume. The corrosion potential was found to be highly negative for control specimens. Specimens exposed to accelerated corrosion test exhibited lower bond strength with higher mass loss and low yield strength in the rebars. Extent of damage due to the effect of corrosion was analysed by physical observations and image analysis. Concrete with Nano Metakaolin exhibited better bond strength and corrosion resistance than those of the other specimens. Effect of nano Cementitious material on improving the micro-structure characteristics of concrete was confirmed by SEM. It was evident from the SEM results that, addition of NMK and NSF in concrete had a significant contribution in improving the bond strength and corrosion resistance.

摘要

混凝土是一种广泛用于建筑的建筑材料，因为它具有优异的力学性能，如抗压强度和与钢筋的结合强度。强度和耐久性是钢筋混凝土结构设计中需要满足的关键因素。本文的目的是通过使用纳米偏高岭土（NMK）和纳米硅粉（NSF）等辅助纳米胶凝材料来提高混凝土的粘结强度和抗腐蚀性能。添加纳米胶凝材料将有助于通过改善微观结构来提高混凝土的力学性能。混凝土与钢筋之间的有效结合，保证了结构构件之间的荷载转换。将样品暴露于氯化物诱导的加速腐蚀试验或氯化物诱导的浸渍腐蚀试验。进行了调查以评估混凝土的抗压强度、粘结强度和耐腐蚀性。与含有纳米偏高岭土和纳米硅粉的混凝土相比，含有缓蚀剂/防腐蚀涂层的试样的粘结强度较差。发现对照样品的腐蚀电位高度为负值。暴露于加速腐蚀试验的试样表现出较低的结合强度，钢筋的质量损失较高，屈服强度较低。通过物理观察和图像分析来分析腐蚀作用造成的损坏程度。含有纳米偏高岭土的混凝土比其他试样表现出更好的粘结强度和耐腐蚀性。扫描电镜证实了纳米胶凝材料对改善混凝土微观结构特性的影响。从扫描电镜结果可以看出，在混凝土中添加 NMK 和 NSF 对提高粘结强度和耐腐蚀性有显着贡献。