Analytical studies on concrete columns reinforced with macroscopic cnt bars

Abstract

The concrete structures and structural elements had been reinforced newlinewith natural fibres, synthetic fibres, steel fibres and carbon fibres. The added fibres newlineaccount for the ductility and bridging cracks. However the initiation of the micro newlinecracks could not be avoided. The delay in development of cracks had been newlineobserved whereas the arrest of cracks and their propagation is still under research. newlineThis research focuses on using Carbon Nanotubes (CNTs) as fibres as well as newlinemacroscopic reinforcement bars in concrete columns. newlineThe first phase of research focuses of finite element modelling of newlineCarbon Nanotube concrete matrix for three grades of concrete namely M40, M60 newlineand M120. Representative Elementary Volume (REV) was adopted and one newlineeighth model depicting the CNT reinforced concrete matrix was simulated using newlineFEA (Finite Element Analysis) software ANSYS. Adopting random orientation newlineof CNTs with fibre volume fractions from 0.1% to 0.9%, the FEA model newlinereplicated exactly the CNT reinforced concrete matrix. Upon evaluations of the newlinemodel, longitudinal and transverse Young s modulus of elasticity of CNT newlinereinforced concrete was arrived. The graphical plots between various fibre volume newlinefractions and the concrete grade revealed simplified equations for estimating newlineYoung s modulus of CNT reinforced concrete. newlineThe second phase of the research was executed by reinforcing the newlineconcrete columns with macroscopic CNT bars in High Strength Concrete (HSC) newlinefrom grade M100 to M1000. Eighty specimens of short and slender RCC columns newlineand CNT reinforced columns including hexagonal columns were simulated by newlineFEA software ANSYS and their buckling behaviour and load response were newlineanalysed. The buckling load of the columns were obtained by Eigen value newlineBuckling analysis and the nonlinear analyses of columns were executed. The CNT newlinereinforced columns projected enhanced ductility by sustaining heavier loads when newlinecompared with the RC columns and enhanced deformation capability was newlineobserved. newline