Moisture Diffusion in Unsaturated Self-Desiccating Concrete with Humidity-Dependent Permeability and Nonlinear Sorption Isotherm

Saeed Rahimi-Aghdam, Mohammad Rasoolinejad, Zdeněk P. Bažant*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

A nonlinear diffusion model for the drying of concrete, previously developed at Northwestern University and embedded in some design codes, was improved and calibrated on the basis of recent more extensive experimental data from the literature as well as theoretical considerations. The improvements include a new equation for the dependence of the self-desiccation rate on pore humidity and hydration degree; an updated equation for the decrease of moisture permeability at decreasing pore humidity; new equations to predict the permeability and diffusivity parameters from the water-cement and aggregate-cement ratios, hydration degree, the type of concrete; and new equations to capture the nonlinearity of the sorption isotherm as a function of pore humidity and water-cement ratio. Furthermore, the recent idea that the pore humidity drop is the driving force, rather than a side effect, of the autogenous shrinkage is verified.

Original languageEnglish (US)
Article number04019032
JournalJournal of Engineering Mechanics
Volume145
Issue number5
DOIs
StatePublished - May 1 2019

Keywords

  • Aging
  • Cement hydration
  • Diffusivity
  • Drying
  • Experimental verification
  • Numerical analysis
  • Pore pressure
  • Self-desiccation
  • Water transport

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering

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