Controlled growth and ordering of poorly-crystalline calcium-silicate-hydrate nanosheets

Optimising the mesoscale structure of calcium-silicate-hydrate (C-S-H) is critical to achieving durable and sustainable infrastructure using Portland cement concrete. However, control of its intricate formation process, which comprises spatially disordered growth of poorly-crystalline sheets, remains a challenge. Here, through combination of experimental and computer simulation techniques, we report a promising mechanism to control this complex growth process and thereby optimise the C-S-H nanostructure. The pivotal step was utilizing graphene oxide (GO) to restrain the inherent spatial deformations of the C-S-H sheets and guide their concurrent 2D growth and layer-by-layer ordering. Accordingly, we designed a layered GO–C-S-H composite that exhibits 1–2 orders of magnitude improvement in strength and durability compared with C-S-H formed without control. Our findings open a window for nano-engineering of cements and other complex layered materials for ceramic, pharmaceutical and energy applications.