Impact of polymer binders on the aggregation modes of two-pieces CSH composites

Abstract

Using polymer binders in cementitious materials significantly boosts their structural stability and durability for civil engineering applications. This study explored the role of polymeric binders in enhancing the morphological stability of calcium silicate hydrates (CSH) paste through molecular dynamics simulations. Most pure CSH configurations displayed larger voids and decreased stability, especially when the particles were initially spaced further apart. Among the tested polymers, polyvinyl alcohol (PVA) showed the most robust bonding to CSH, attributed to its abundant -OH groups. The integration of polymers led to a shift in aggregation toward a more stable face-to-face (FF) configuration, increasing the contact area, and boosting overall stability. At large distances, the Coulombic force acted aggregation in the initial phase but is soon overtaken by the vdW force, which plays the primary role in driving the aggregation process. These findings corroborate existing theoretical models and introduce fresh insights from experimental organic-inorganic interactions, providing substantial implications for the development of advanced cementitious composites.