TY - JOUR
T1 - X-ray spectromicroscopic study of interactions between NaCl and calcium silicate hydrates
AU - Yoon, Seyoon
AU - Ha, Juyoung
AU - Chae, Sejung Rosie
AU - Kilcoyne, David A.
AU - Monteiro, Paulo J.M.
PY - 2014/2
Y1 - 2014/2
N2 - X-ray diffraction (XRD), scanning transmission X-ray microscopy (STXM) and X-ray absorption near edge structure (XANES) spectra were used to investigate the interactions between sodium chloride (NaCl) and calcium silicate hydrate (C-S-H), the primary binding phase of hydrated Portland cement. XRD analysis indicates the interlayer expansion of C-S-H with a high Ca/Si ratio. Contrast maps of STXM images collected from C-S-Hs with different Ca/Si ratios reacted with NaCl solution reveal that sodium interacts with C-S-H with a low Ca/Si ratio, while chloride is intercalated into the interlayer of C-S-H with a high Ca/Si ratio. Silicon K-edge XANES spectra were analysed to understand the variation in the structure of silicate chains. This revealed that the interaction with the sodium cations depolymerises the silicate chains of C-S-H with a low Ca/Si ratio. The mechanism involved for the selection of adsorbed ions is probably due to the residual charge between the positive charge of interlayer calcium ions and the negative charge of the end group of silicate chains in C-S-H.
AB - X-ray diffraction (XRD), scanning transmission X-ray microscopy (STXM) and X-ray absorption near edge structure (XANES) spectra were used to investigate the interactions between sodium chloride (NaCl) and calcium silicate hydrate (C-S-H), the primary binding phase of hydrated Portland cement. XRD analysis indicates the interlayer expansion of C-S-H with a high Ca/Si ratio. Contrast maps of STXM images collected from C-S-Hs with different Ca/Si ratios reacted with NaCl solution reveal that sodium interacts with C-S-H with a low Ca/Si ratio, while chloride is intercalated into the interlayer of C-S-H with a high Ca/Si ratio. Silicon K-edge XANES spectra were analysed to understand the variation in the structure of silicate chains. This revealed that the interaction with the sodium cations depolymerises the silicate chains of C-S-H with a low Ca/Si ratio. The mechanism involved for the selection of adsorbed ions is probably due to the residual charge between the positive charge of interlayer calcium ions and the negative charge of the end group of silicate chains in C-S-H.
UR - http://www.scopus.com/inward/record.url?scp=84892174774&partnerID=8YFLogxK
U2 - 10.1680/macr.13.00244
DO - 10.1680/macr.13.00244
M3 - Article
AN - SCOPUS:84892174774
SN - 0024-9831
VL - 66
SP - 141
EP - 149
JO - Magazine of Concrete Research
JF - Magazine of Concrete Research
IS - 3
ER -