Study on dynamic mechanical properties of carbon nanotubes reinforced concrete subjected to freeze–thaw cycles

Abstract

AbstractAs a nanometer material, carbon nanotubes can inhibit the expansion of microcracks and is of great significance to improve the mechanical properties and durability of concrete. In order to explore the mechanism of dynamic mechanical properties enhancement of carbon nanotube reinforced concrete under impact load after freeze–thaw cycles, the dynamic compression test of carbon nanotube reinforced concrete samples was carried out by using the control variable method with freeze–thaw cycles and impact air pressure as variables. The results showed that under the same impact pressure, the peak stress of carbon nanotube reinforced concrete sample decreased gradually with the increase of freeze–thaw cycles. The corresponding strain increased slightly, and the stress–strain curve moved to the right and down as a whole. Under the same freeze–thaw cycle, the peak stress of carbon nanotube reinforced concrete sample increased with the increase of strain rate, and the dynamic strength growth factor DIF also increased, showing an obvious strain rate strengthening effect. In addition, under the same freeze–thaw cycles and external impact load, the dynamic strength of carbon nanotube concrete is 41.97 and 54.21 MPa, respectively, which is 22.27 and 25.81% higher than that of ordinary plain concrete. The results show that carbon nanotube reinforced concrete samples have higher dynamic mechanical properties and freeze–thaw cycle resistance than ordinary plain concrete samples.