Nanoscale Indentation Methods for Mechanical Characterization of C-S-H

Calcium-silicate-hydrate (C-S-H), the primary hydration product in Portland cement, plays a crucial role in determining the strength and durability of cement-based materials. Due to its complex, multi-scale microstructure and variable chemical composition, traditional testing methods fall short in fully characterizing its intrinsic properties. This chapter focuses on nanoscale indentation techniques—specifically nanoindentation and atomic force microscopy (AFM)—for investigating the mechanical behavior of C-S-H. Nanoindentation provides quantitative insights into hardness, elastic modulus, and creep behavior, while AFM enables high-resolution measurements of surface interactions and stiffness at the nanometer scale. Advances in coupled technologies, such as SEM and X-ray tomography, further enhance the identification of hydration phases. Emphasis is placed on how these techniques contribute to understanding the structure–property relationships in C-S-H, particularly under varying Ca/Si ratios and hydration conditions. This chapter highlights recent developments, testing principles, and analysis approaches, offering guidance for future research aimed at optimizing the mechanical performance of cementitious materials through nanoscale characterization.