Molecular Dynamics Simulation of CNT Reinforced Cement: A Step Toward Sustainable Construction

This study explores the potential of carbon nanotubes (CNTs) to enhance cement mechanical properties, aiming to develop more sustainable materials and reduce the industry’s carbon footprint. Using molecular dynamics (MDs) simulations, the effect of pristine and carboxyl-functionalized single-walled CNT incorporation on the mechanical properties of 11 Å tobermorite, a model for calcium–silicate–hydrate (CSH), was analyzed. The results demonstrated a significant increase in the elastic modulus (E) of the composite, with CNT content directly influencing this enhancement. Specifically, E increased from 77.05 GPa to 81.93 GPa upon the incorporation of pristine CNTs and further increased to 97.87 GPa with the introduction of carboxyl-functionalized CNTs. Composites containing functionalized CNTs exhibited a more pronounced increase in E, as the carboxyl groups formed hydrogen bonds with the tobermorite structure, thereby reinforcing interactions and improving mechanical properties. Thus, increasing functionalization allows for lower reinforcement content, reducing costs and CNT aggregation, as observed in experimental studies. These findings underscore the potential of functionalized CNTs to strengthen cementitious materials, offering an alternative to traditional additives. This approach could contribute to reducing the carbon emissions associated with cement production, thereby supporting the development of more sustainable and environmentally friendly cement alternatives.