Preparation and load-deformation characterization of carbon nanotube-reinforced foam concrete

Abstract

In this study, uniaxial compression tests and digital speckle collection technology are used to study the applicability of carbon nanotube-reinforced foam concrete, which is prepared with micro-doped carbon nanotubes, as a pressure-relieving energy-absorbing material. Moreover, the effects of different carbon nanotube contents on the load-deformation characteristics, including the stress-strain response, displacement field, maximum shear strain field, Poisson's ratio and energy drop release law, of carbon nanotube-reinforced foam concrete materials are investigated. The results show that the ultimate strain of the carbon nanotube-reinforced foam concrete materials is much larger than that of brittle materials, such as ordinary concrete and rock. As the carbon nanotube content increases, the carbon nanotube-reinforced foam concrete specimen provides higher post-peak compressive resistance under certain deformation conditions. This property is a performance requirement of surrounding rock support pressure relief materials. It is proposed that the deformation localization starting conditions of the carbon nanotube-reinforced foam concrete specimens are divided into strain decision conditions and stress decision conditions. The strain decision condition is 86.8% of the peak strain, and the stress decision condition is 80.2% of the peak stress. It is suggested that the strain condition is more reasonable than the stress condition as the starting condition for deformation localization in the carbon nanotube-reinforced foam concrete specimens. So on after deformation localization starts, the corresponding Poisson's ratio-strain curve exhibits a steep increase. The energy release process of carbon nanotube-reinforced foam concrete is measured by the energy drop release rate. The energy release process of the carbon nanotube-reinforced foam concrete specimens with 0.05% carbon nanotubes best satisfies the surrounding rock support pressure relief requirements.