Finite Element-Based Methodology for the Evaluation of the Flexural Properties of Cement-Based Nanocomposites

The main goal of the present article was to develop a methodology for the calculation of the flexural properties of a cement-based matrix with different multi-walled carbon nanotubes’ (CNTs) volume fraction as a reinforcement at early age. The homogenization tool of the ANSA® software package was exploited for the modelling of the inclusion geometries in a cubic matrix and for mesh generation. A Representative Volume Element (RVE) was constructed with either random orientation tensor algorithm or periodic geometry algorithm tools and for different concentrations of the nano-reinforcement. Finite element modelling (FEM) of the pre-cracked specimens for flexural tests followed, and the numerical results were compared against the experimental ones. Different input parameters were considered, including the reinforcement Poisson’s ratio (νCNT) as well as the effective elastic modulus (ECNT) to predict the flexural behaviour of the nano-reinforced matrices. It was found that both parameters play a pivotal role for the numerical simulation and the best simulation results were obtained for CNTs’ effective elastic modulus ECNT = 470 GPa and Poisson’s ratio of νCNT = 0.10 values for the two (2) different investigated concentrations of carbon nanotubes (0.6 and 1.2%, respectively) in the cementitious matrix.