• C-S-H exhibits a complex nanostructure with variable stoichiometry and morphology, directly influencing concrete strength and durability.
• Advanced characterization techniques, including solid-state NMR and synchrotron XRD, provide critical insights into C-S-H's atomic arrangement and growth mechanisms.
• Molecular dynamics simulations reveal that water dynamics and interlayer ions significantly affect C-S-H's mechanical properties, guiding the design of stronger, more sustainable cements.
• Understanding C-S-H structure is essential for developing low-carbon cements with reduced clinker content while maintaining or improving performance.