Thermodynamics of hindered adsorption and its implications for hardened cement paste and concrete

The dominant mechanism of shrinkage and creep of concrete at working stress levels is presently believed to consist in a coupling between change of thickness and diffusion in some sort of mono- or multi-molecular layers of water confined by an adsorbent solid. The classical solution thermodynamics and the usual formulation of surface thermodynamics are both inadequate for a rigorous treatment of this phenomenon. In the latter case this is due to the fact that a surface phase of limiting zero thickness is implied at the outset. In the present paper, thermodynamics of hindered adsorption which is consistent with the basic concepts of surface thermodynamics but free from the above shortcoming is developed.