Dielectric properties of Portland cement at different water cement ratio

Resumen del póster presentado al 7th International Discussion Meeting on Relaxations in Complex Systems: "New results, Directions and Opportunities", celebrado en Barcelona (España) del 21 al 26 de julio de 2013.Portland cement is the most used construction material and it is mainly composed of alite (calcium silicates), belite, aluminate and ferrite phase. When Portland cement is hydrated, the chemical reactions taking place are generally more complex than simple conversions of anhydrous compounds into the corresponding hydrates. During hydration a complex random network is developed and a nanostructure with different length scales from < 1 to 20nm is formed. By broadband dielectric spectroscopy, it is possible to analyze the dynamic of water as well as other components in these complex materials. In this work we investigate the dielectric and calorimetric properties of water confined in Portland cement (CEM II- Sweden) in a temperature range from 110K to 300K and in the frequency range of 10-2 to 107 Hz. Samples have been prepared with different water/ cement ratio from 0.25 to 0.50. Four different relaxation processes were observed for all the hydration levels analyzed. Different characteristics of these processes will be discussed in this work in relation with the nanostructure developed by the cement.Peer reviewe