Optimization of the carbon nanotubes reinforcement in cement-based materials

Abstract

During the last decades, composites had been successfully strengthened at the micrometer scale using different types of reinforcements, e.g., carbon or even glass fibers. Over the past years, the development of carbon nanotubes and graphene enabled the reinforcement of cement-based materials at the nanoscale. The produced nanocomposites have increased the mechanical properties as compared to non-reinforced materials and especially on the “effective” properties such as modulus of elasticity and Poisson’s ratio. In several cases and for compatibility issues, it is of imperative importance to “tailor” a nano-reinforced composite with specific material properties, such as the modulus of elasticity and the Poisson’s ratio. To this end, a methodology to identify the optimal material synthesis needs to be effectively addressed. The present article presents an optimization method to quantify the appropriate volume fraction of graphene nanostructures to design a cement-based nanocomposite with a target value of the effective modulus. The Interior Point Optimization (IPOpt) algorithm is used for the optimization iterations applied to the homogenization properties calculated by ANSA® pre-processor. A comparison was made between three different optimization cases, having different maximum number of iterations and a different objective value. The calculated effective modulus and volume fraction were correlated with the target experimental values.