多壁碳纳米管增强混凝土的断裂性能

Fracture Properties of Multi-Walled Carbon Nanotubes Reinforced Concrete

将多壁碳纳米管(MWCNTs)掺入混凝土中能提高混凝土的断裂韧性。通过带预制裂缝的三点弯曲梁断裂试验对MWCNTs增强混凝土的断裂性能进行了研究,采用双K断裂参数分析了MWCNTs增强混凝土的断裂性能。结果表明:MWCNTs提高了混凝土的断裂韧性。当MWCNTs的掺量为0.10%(占水泥的质量分数)时,混凝土的28 d抗压强度和劈裂抗拉强度分别提高了1.7%和11.7%;当MWCNTs的掺量为0.15%时,混凝土的起裂韧度、失稳韧度和断裂能分别提高了31.0%、32.4%和24.6%。MWCNTs主要通过桥接混凝土里的微裂缝和增强骨料界面过渡区,延缓微裂缝的扩展。

Incorporating multi-walled carbon nanotubes(MWCNTs) into concrete can improve the fracture toughness of concrete.The fracture properties of MWCNTs reinforced concrete were examined via three-point bending beam fracture tests. The fracture parameters of MWCNTs reinforced concrete were analyzed by using the double K fracture parameters. The results show that MWCNTs can improve the fracture toughness of concrete. When the content of MWCNTs is 0.10%, the 28-d compressive strength and splitting tensile strength of concrete are increased by 1.7% and 11.7%, respectively. When the content of MWCNTs is 0.15%, the initial fracture toughness, unstable fracture toughness and fracture energy of concrete are increased by 31.0%, 32.4% and 24.6%,respectively. It is indicated that MWCNTs delay the propagation of micro-cracks by bridging across the micro-cracks in concrete and strengthening the interfacial transition zone.