Premium
Crystallization of calcium silicate hydrates on the surface of nanomaterials
Author(s) -
Li Hui,
Du Tao,
Xiao Huigang,
Zhang Qiangqiang
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14842
Subject(s) - nanomaterials , materials science , nanocrystalline material , crystallization , chemical engineering , anatase , transmission electron microscopy , scanning electron microscope , calcium silicate hydrate , graphene , crystal structure , nanotechnology , nanocrystal , lattice constant , crystallography , diffraction , composite material , chemistry , cement , photocatalysis , optics , organic chemistry , physics , catalysis , engineering
The poorly crystalline calcium silicate hydrate (C‐S‐H) is the primary binding phase in portland cement concrete. In this paper, the influence of adding anatase phase nano‐TiO 2 , nano‐SiO 2 , graphene oxide ( GO ), and multiwalled carbon nanotubes ( CNT ) on the crystallization and morphology of C‐S‐H are systematically investigated through tests. C‐S‐H gels were prepared using the double decomposition method, and the nanomaterial additions of nano‐TiO 2 , nano‐SiO 2 , GO , and CNT were 2 wt%, 2 wt%, 0.5 wt%, and 0.5 wt%, respectively. X‐ray diffraction ( XRD ) results show that a more crystalline nanostructure of C‐S‐H is induced by the addition of nano‐TiO 2 or GO . This phenomenon is further confirmed by the transmission electron microscopy ( TEM ) observations. The TEM observations demonstrate that C‐S‐H would grow on the crystal face of TiO 2 to form nanocrystalline regions with a lattice fringe spacing of 3.0 Å. When incorporated with GO , it will form a square lattice structure with a lattice constant of 3.1 Å on the surface of GO and later change to the lattice fringe structure with a spacing of 3.1 Å on the region bit away the GO surface. However, when adding nano‐SiO 2 or CNT , these nanocrystalline regions are not observed. Further characterization through scanning electron microscopy ( SEM ) and atomic force microscopy ( AFM ) has been performed to investigate the effect of nanomaterials on C‐S‐H morphology. Different nanomaterials take a different morphology of C‐S‐H: sheet‐shape structures for pure C‐S‐H, rod‐shape with for C‐S‐H with nano‐TiO 2 , and granular agglomeration for C‐S‐H with nano‐SiO 2 . C‐S‐H with GO or CNT forms a structure of C‐S‐H growing on the templates.