High resolution quasi-elastic neutron scattering is used to investigate the slow dynamics of hydration water confined in calcium silicate hydrate gel in an aged cement paste at supercooled temperatures. A super-Arrhenius to Arrhenius dynamic crossover of the average translational relaxation time <tau > as a function of the inverse temperature is observed at T(L) = 231 +/- 5 K, which coincides with a prominent peak in the differential scanning calorimetry cooling scan. The dynamic susceptibility chi(T)(t) calculated using the experimentally determined temperature dependence of the self-intermediate scattering function shows direct evidence of the enhanced dynamic fluctuations and the associated growth in size of the dynamic heterogeneity in the confined water on approaching T(L).
Observation of Dynamic Crossover and Dynamic Heterogeneity in Hydration Water Confined in Aged Cement Paste / Y. Zhang; M. Lagi; F. Ridi; E. Fratini; P. Baglioni; E. Mamontov; S.-H. Chen. - In: JOURNAL OF PHYSICS. CONDENSED MATTER. - ISSN 0953-8984. - STAMPA. - 20:(2008), pp. 502101-1-502101-6. [10.1088/0953-8984/20/50/502101]
Observation of Dynamic Crossover and Dynamic Heterogeneity in Hydration Water Confined in Aged Cement Paste
LAGI, MARCO;RIDI, FRANCESCA;FRATINI, EMILIANO;BAGLIONI, PIERO;
2008
Abstract
High resolution quasi-elastic neutron scattering is used to investigate the slow dynamics of hydration water confined in calcium silicate hydrate gel in an aged cement paste at supercooled temperatures. A super-Arrhenius to Arrhenius dynamic crossover of the average translational relaxation time
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