Effect of nanomaterials (carbon nanotubes, nano-silica, graphene oxide) on bond behavior between concrete and reinforcing bars
Dongsun Hwangbo, Donghee Son, Heongwon Suh, Jaebum Sung, Baek-Il Bae, Sungchul Bae, Hongyun So, Chang-Sik Choi
Abstract
The purposes of this study are (i) to evaluate the mechanical properties of triple hybrid-reinforced concrete mixed with carbon nanotubes, nano-silica, and graphene oxide and (ii) to determine the effect of these properties on the bond strength. First of all, compressive strength and splitting tensile strength tests were performed to evaluate the mechanical properties of triple hybrid-reinforced concrete. It has been observed that the flexural strength of concrete increases and the Poisson's ratio and volumetric strain decrease with the incorporation of nano-materials, and the effect is most pronounced when graphene oxide is added. Next, pull-out tests were conducted using a total of 21 specimens of triple hybrid-reinforced concrete. Similarly to the material test results, the bond performance of triple hybrid-reinforced concrete was found to be the highest, which can be attributed to the minimal volumetric deformation of the concrete. By this, the bond strength of Triple hybrid-reinforced concrete was evaluated, taking into account the mechanical properties. When considering Poisson's ratio and flexural strength, it was possible to predict them relatively accurately. In future research, it will be necessary to analyze additional mechanical properties such as friction coefficient and shrinkage strain of nano concrete to incorporate them into the bond strength model.