Application of Digital-Image-Based Models to Microstructure, Transport Properties, and Degradation of Cement-Based Materials.
Application of Digital-Image-Based Models to
Microstructure, Transport Properties, and Degradation of
Bentz, D. P.; Garboczi, E. J.; Martys, N. S.
Modelling of Microstructure and Its Potential for
Studying Transport Properties and Durability. 1996,
Kluwer Academic Publishers, Jennings, H., Editor(s),
167-185 pp, 1996.
building technology; cements; cement based materials;
computer models; microstructure; transport properties;
As multi-phase composites, cement-based materials have
physical properties that are strongly influenced by the
volume fractions and topologies of the individual
phases. Because of their inherent random nature, these
materials often defy a simple geometrical description.
The use of digital-image-based models allows one to
realistically represent this class of materials, as
resultant microstructures can be quickly quantified with
respect to the volume fraction and interconnectivity or
percolation of each phase or any combination of phases.
In addition, physical properties such as diffusivity and
permeability can be conveniently computed using
finite-difference or finite-element techniques. These
computer modeling techniques will be demonstrated for
microstructural models of these materials at two scales:
hydrated cement paste at the micrometer level and
calcium silicate hydrate gel at the nanometer level.
The properties computed for the gel at the nanometer
level can be used as input for the micrometer-level
model. Examples of the importance of volume fraction
and phase topology in determining physical properties
will be presented for each of the four major phases of
cement paste: anhydrous cement, capillary porosity,
calcium silicate hydrate gel, and calcium hydroxide.
Results of the models are compared to existing
experimental data, and good agreement is observed.
These techniques are seen as one critical link in
developing sound scientific relationships between the
microstructure and the transport properties and
durability of cement-based materials.