Bei He , Xinping Zhu , Hongen Zhang , Aiguo Wang , Daosheng Sun , Nemkumar Banthia , Zhengwu Jiang
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引用次数: 0
Abstract
The interfacial bonding between steel fibers and Ultra-High Performance Concrete (UHPC) matrix is pivotal for the mechanical properties in extreme environments. Herein, a surface nanoengineering approach using the sol-gel method was reported to enhance the resistance of fiber bonding to varying cryogenic and elevated exposures (−170 °C ∼ 200 °C). Additionally, the interfacial bonding and failure of the steel fiber-matrix interface were evaluated by in-situ acoustic emission (AE) monitoring and a series of microscopic characterizations. The result indicated that the deposition of a nano-SiO2 coating with a film structure thickness of approximately 150 nm on fiber surface could be achieved. The coating exhibited excellent cryogenic resistance but inferior elevated resistance, as elevated temperatures caused the coating to crack and corrode. After modification, the interfacial bonding stability exposed to thermal variations was enhanced. At ambient temperature, the bond strength of the modified fibers increased by 44.68 % compared to before modification, while that increased by 1.54 %–13.49 % in a single thermal-variations cycle compared to the ambient modified group. Interface enhancement arises from imbalances in nanocoating thermal stability, moisture phase changes, properties of three-phase interface transition zone, and thermal expansion coefficient disparities. Those findings provide new insight into the attempts to improve the mechanical and durability properties of concrete under extreme temperature environments.
期刊介绍:
Cement & concrete composites focuses on advancements in cement-concrete composite technology and the production, use, and performance of cement-based construction materials. It covers a wide range of materials, including fiber-reinforced composites, polymer composites, ferrocement, and those incorporating special aggregates or waste materials. Major themes include microstructure, material properties, testing, durability, mechanics, modeling, design, fabrication, and practical applications. The journal welcomes papers on structural behavior, field studies, repair and maintenance, serviceability, and sustainability. It aims to enhance understanding, provide a platform for unconventional materials, promote low-cost energy-saving materials, and bridge the gap between materials science, engineering, and construction. Special issues on emerging topics are also published to encourage collaboration between materials scientists, engineers, designers, and fabricators.