Creep, shrinkage and mechanical properties of concrete reinforced with different types of carbon nanotubes

•Influence of different types of carbon nanotubes on properties of concrete.•Long-term creep and shrinkage of concrete.•Fresh properties, compressive strength and elastic modulus of concrete. This study investigates the influence of incorporating different types of carbon nanotubes (CNTs) on the long-term creep and shrinkage of concrete. Concretes were produced with 0.05–0.5% of unfunctionalized and functionalized CNTs of distinct aspect ratios and water to cement ratios of 0.35–0.55. The influence of CNTs on main fresh and mechanical properties was also analysed. The incorporation of CNTs were able to improve the compressive strength up to 21%, but only slightly increased the modulus of elasticity. Long time-dependent shrinkage and creep of CNT-reinforced concrete were reduced up to 15% and 18% as compared to reference concrete, respectively. Early shrinkage could be reduced up to 54%. CNTs of different aspect ratio equally affected creep, but CNTs of lower aspect ratio were more effective in shrinkage reduction.