Effect of hydration on the dielectric properties of C-S-H gel.
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.
Centro de Fisica de Materiales (CSIC, UPV∕EHU), Paseo Manuel de Lardizabal 5, 20018, San Sebastián, Spain. scerveny@ehu.es
Silvina
S
Cerveny
Silvia
S
Arrese-Igor
Jorge S
JS
Dolado
Juan J
JJ
Gaitero
Angel
A
Alegría
Juan
J
Colmenero
D017610:Calcium Compounds / Q000737:chemistry*; D058266:Dielectric Spectroscopy; D004583:Electrons; D005782:Gels / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
D017610:Calcium Compounds; D005782:Gels; D017640:Silicates; D014867:Water; D006859:Hydrogen; C031293:calcium silicate