Effect of hydration on the dielectric properties of C-S-H gel

J Chem Phys. 2011 Jan 21;134(3):034509. doi: 10.1063/1.3521481.

Abstract

The behavior of water dynamics confined in hydrated calcium silicate hydrate (C-S-H) gel has been investigated using broadband dielectric spectroscopy (BDS; 10(-2)-10(6) Hz) in the low-temperature range (110-250 K). Different water contents in C-S-H gel were explored (from 6 to 15 wt%) where water remains amorphous for all the studied temperatures. Three relaxation processes were found by BDS (labeled 1 to 3 from the fastest to the slowest), two of them reported here for the first time. We show that a strong change in the dielectric relaxation of C-S-H gel occurs with increasing hydration, especially at a hydration level in which a monolayer of water around the basic units of cement materials is predicted by different structural models. Below this hydration level both processes 2 and 3 have an Arrhenius temperature dependence. However, at higher hydration level, a non-Arrhenius behavior temperature dependence for process 3 over the whole accessible temperature range and, a crossover from low-temperature Arrhenius to high-temperature non-Arrhenius behavior for process 2 are observed. Characteristics of these processes will be discussed in this work.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium Compounds / chemistry*
  • Dielectric Spectroscopy
  • Electrons
  • Gels / chemistry
  • Hydrogen / chemistry*
  • Silicates / chemistry*
  • Temperature
  • Water / chemistry

Substances

  • Calcium Compounds
  • Gels
  • Silicates
  • Water
  • Hydrogen
  • calcium silicate