Nanosilica-based post-treatment of hardened cement-based materials: The underlying physics

We study here the imbibition of a nanosilica-based product in a hardened cement-based material along with the consequences of the product on transport properties. We use X-ray microtomography to assess the liquid ingress in the cement-based matrix as a function of time. We moreover measure the consequences of the nanosilica treatment on water absorption and chloride penetration. Our results suggest that nano-silica imbibition in cement-based materials involves some deep particle clogging and, in turn, some phase separation in the porous cement-based material. As a consequence, the effective local concentration of nano-silica increases in a clogged zone located between a critical clogging depth and the surface. In this zone, the silica concentration level in the porosity allows for the formation of a physical barrier inside the material, which can, in turn, affect transport properties.

Automated summary

We investigated the penetration and transport properties of a nanosilica-based product in hardened cement-based materials. X-ray microtomography was used to study liquid ingress as a function of time. Additionally, water absorption and chloride penetration were measured to evaluate the effects of nanosilica treatment. Our findings suggest that nanosilica imbibition in cement-based materials leads to particle clogging and phase separation, affecting local concentration and transport properties.