title: Quantitative X-ray pair distribution function analysis of nanocrystalline calcium silicate hydrates: a contribution to the understanding of cement chemistry.
abstract: The structural evolution of nanocrystalline calcium silicate hydrate (C-S-H) as a function of its calcium to silicon (Ca/Si) ratio has been probed using qualitative and quantitative X-ray atomic pair distribution function analysis of synchrotron X-ray scattering data. Whatever the Ca/Si ratio, the C-S-H structure is similar to that of tobermorite. When the Ca/Si ratio increases from ∼0.6 to ∼1.2, Si wollastonite-like chains progressively depolymerize through preferential omission of Si bridging tetrahedra. When the Ca/Si ratio approaches ∼1.5, nanosheets of portlandite are detected in samples aged for 1 d, while microcrystalline portlandite is detected in samples aged for 1 year. High-resolution transmission electron microscopy imaging shows that the tobermorite-like structure is maintained to Ca/Si > 3.
authors.affiliation: D3E/SVP, BRGM (French Geological Survey) , 3 Avenue Claude Guillemin, Orléans, 45060, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Grangeon
authors.affiliation: ISTerre, CNRS and Université Grenoble Alpes , Grenoble, 38041, France.
authors.forename: Alejandro
authors.identifier: https://orcid.org/0000-0001-5073-9629
authors.initials: A
authors.lastname: Fernandez-Martinez
authors.affiliation: CINaM UMR 7325, Université Aix-Marseille, Marseille, 13288, France; CINaM UMR 7325, CNRS, Marseille, 13288, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Baronnet
authors.affiliation: D3E/SVP, BRGM (French Geological Survey) , 3 Avenue Claude Guillemin, Orléans, 45060, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Marty
authors.affiliation: ESRF, The European Synchrotron , 71 Avenue des Martyrs, Grenoble, 38000, France.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Poulain
authors.affiliation: Synchrotron Soleil , L'Orme des Merisiers Saint-Aubin, Gif-sur-Yvette Cedex, BP 48 91192, France.
authors.forename: Erik
authors.initials: E
authors.lastname: Elkaïm
authors.affiliation: Scientific Division, Andra , 1-7 Rue Jean Monnet, Parc de la Croix Blanche, Chatenay-Malabry Cedex, 92298, France.
authors.forename: Cédric
authors.initials: C
authors.lastname: Roosz
authors.affiliation: D3E/SVP, BRGM (French Geological Survey) , 3 Avenue Claude Guillemin, Orléans, 45060, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Gaboreau
authors.affiliation: Scientific Division, Andra , 1-7 Rue Jean Monnet, Parc de la Croix Blanche, Chatenay-Malabry Cedex, 92298, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Henocq
authors.affiliation: D3E/SVP, BRGM (French Geological Survey) , 3 Avenue Claude Guillemin, Orléans, 45060, France.
authors.forename: Francis
authors.initials: F
authors.lastname: Claret
keywords: C–S–H; calcium silicate hydrates; pair distribution function; transmission electron microscopy