Lightweight foamed concrete (LWFC) is an innovative construction material, mainly because it significantly reduces the structural load, offers superior thermal insulation, sound absorption, fire resistance and promotes sustainable energy-efficient construction practices. This thesis investigates the effect of mixing time and addition of functionalized carbon nanotubes (FCNTs) on the fresh and hardened properties of lightweight foamed concrete. The base mixture was composed of cement, water, superplasticizer, viscosity enhancing agent (VEA), and foaming agent. Two different mixing time were employed to produce specimens with distinct fresh densities. Furthermore, additional specimens were prepared by introducing FCNTs into the mixture to enhance the mechanical properties.