Crack resistance properties of carbon nanotube-modified concrete
Yingjia Lan, Bingmiao Zheng, Tao Shi, Chengchang Ma, Yanming Liu, Zhifang Zhao
Abstract
Incorporating carbon nanotubes (CNTs) into concrete can improve its fracture toughness. The crack resistance properties of reinforced concrete with CNTs were tested by ring test and three-point bending beam fracture test. The fracture parameters of reinforced concrete with CNTs were analysed by using double-K fracture parameters and the results showed that CNTs can improve the crack resistance properties. When the CNT content was 0.10 wt%, the compressive strength at 28 days and the splitting tensile strength of concrete were increased by 1.7 and 11.7%, respectively. When the CNT content was 0.15 wt%, the cracking time of concrete under semi-closed and closed conditions was extended by 42.1 and 41.2%, respectively. The initiation fracture toughness, the unstable fracture toughness and the fracture energy of concrete were increased by 31.0, 32.4 and 24.6%, respectively. It was found that CNTs delay the propagation of micro-cracks by bridging across the micro-cracks in concrete and strengthening the interfacial transition zone.