title: Nano-scale mechanics of colloidal C-S-H gels.
abstract: Gels of calcium-silicate-hydrates (C-S-H) are the glue that is largely responsible for the mechanical properties of cement. Despite their practical relevance, their nano-scale structure and mechanics are still mainly unexplored, because of the difficulties in characterizing them in a complex material like cement. We propose a colloidal model to investigate the gel mechanics emerging in the critical range of length-scales from several tens to hundreds of nanometers. We show that the size polydispersity of the hydrates and size-dependent effective interactions can explain the mechanical heterogeneities detected in nano-indentation experiments. We also show how these features control the arising of irreversible structural rearrangements under deformation, which are good candidates as nano-scale mechanisms underlying mechanical aging and slow structural relaxation in the gels.
authors.affiliation: School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK. enrico.masoero@newcastle.ac.uk.
authors.forename: Enrico
authors.initials: E
authors.lastname: Masoero
authors.forename: Emanuela
authors.initials: E
authors.lastname: Del Gado
authors.forename: Roland J-M
authors.initials: RJ
authors.lastname: Pellenq
authors.forename: Sidney
authors.initials: S
authors.lastname: Yip
authors.forename: Franz-Josef
authors.initials: FJ
authors.lastname: Ulm