Effects of polyurethane–silica nanohybrids as additives on the mechanical performance enhancement of ordinary Portland cement paste

Using organic–inorganic nanocomposites to control cement hydration products is a promising method to improve the mechanical properties of cement-based materials. In this work, novel silica nanohybrids with flexible polyurethane (PU) were synthesized and used as highly efficient mechanical-performance enhancement agents for cement paste. Compared to pure cement pastes, the flexural strength and compressive strength of cement pastes with PU-silica nanohybrids obviously increased at a dosage of 1.0‰. XRD, SEM, and cement-hydration tests were also conducted to explore the mechanism of PU-silica nanohybrids on cement paste. The addition of PU-silica nanohybrids led more C-S-H appeared in the cement hydration products, which was also conducive to increasing the mechanical performance of the cement paste.