Magnetic enhancement of carbon nanotube concrete compressive behavior

Abstract

A novel exploratory investigation was conducted into the feasibility of fabricating new smart concrete composites as well as reducing Carbon Nanotube (CNT) content while achieving higher compressive strength via electromagnetism. Hence, some experiments were conducted on cylindrical concrete specimens containing different CNT contents of up to 0.04%, wherein the effect of Alternating Magnetic Field (AMF) on the compressive strength of 7 and 28-day specimens was evaluated, using a specialized setup capable of subjecting the specimens to both AMF and compressive force, simultaneously. It was observed that exposing either fresh or hardened concrete to AMF improved compressive strength. As CNT content was increased, AMF was more efficient in enhancing compressive strength. Magnetizing the specimens containing 0.02% CNTs yielded a higher strength than adding 0.04% CNTs without magnetization, leading to a more economical CNT concrete. Moreover, due to magnetizing fresh concrete, CNTs were oriented in the direction of AMF. With better electric conductivity of the composite due to more uniform orientation of CNTs, this method could be useful in enhancing self-sensing properties of cementitious composites. Finally, magnetizing hardened concrete improved compressive strength in real-time. Therefore, this can be considered as a clue to developing a new generation of smart actuating composites.