Nonlinear water diffusion in nonsaturated concrete

Z. P. Bažant*, L. J. Najjar

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

542 Scopus citations

Abstract

The equations governing drying and wetting of concrete are formulated, assuming the diffusivity and other material parameters to be dependent on pore humidity, temperature and degree of hydration. By fitting of computer solutions for slabs, cylinders and spheres against numerous test data available in the literature it is found that the diffusion coefficient decreases about 10 to 20 times when passing from 0.9 to 0.6 pore humidity. The problem is thus strongly nonlinear. Dependence on temperature is found to agree satisfactorily with the rate process theory. Effect of temperature on equilibrium pore humidity is also studied. The aging effect is defined by means of an equivalent hydration period. To enable easy prediction of drying of simple bodies, charts for the solution in terms of nondimensional variables are presented. Finally, correlation to the diffusion in a saturated concrete is discussed.

Original languageEnglish (US)
Pages (from-to)3-20
Number of pages18
JournalMatériaux et Constructions
Volume5
Issue number1
DOIs
StatePublished - Jan 1 1972

ASJC Scopus subject areas

  • Engineering(all)

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