Heats as well as entropies of water and nitrogen adsorption on hardened cement pastes of various pore structures were computed. Water vapor adsorption is accompanied by a decrease in integral entropy relative to the liquid state, while nitrogen adsorption Ls accompanied by an increase in integral en
Thermodynamics of hindered adsorption and its implications for hardened cement paste and concrete
✍ Scribed by Z.P. Bažant
- Publisher
- Elsevier Science
- Year
- 1972
- Tongue
- English
- Weight
- 760 KB
- Volume
- 2
- Category
- Article
- ISSN
- 0008-8846
No coin nor oath required. For personal study only.
✦ Synopsis
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 multimolecular 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.
📜 SIMILAR VOLUMES
The diffusion and sorption behaviour in disc shaped samples of hardened cement paste (HCP) has been studied for the radionuclides C1-36, 1-125 and Cs-134 using the through-diffusion technique. The experiments were performed both in controlled atmosphere glove boxes (Pco2 = 10-5.Sbar) and under atmos
Creep and creep recovery tests have been performed in bending on beams of hardened cement paste, under controlled conditions at 60% R.H. and 35°C, recording deformations from very short times (O.Is) to 7 days. Recoverable creep curves have been analyzed considering viscoelastic chain models involvin