A Hard Core/Soft Shell Microstructural Model for Studying Percolation and Transport in Three-Dimensional Composite Media

Published

January 1, 1999

Author(s)

Dale P. Bentz, Edward J. Garboczi, Kenneth A. Snyder

Abstract

This user's manual provides documentation and computer program listings for the three-dimensional hard core/soft shell microstructure model developed at the National Institute of Standards and Technology. The model has been developed to represent the three phase microstructure of a concrete composite consisting of a bulk matrix (cement paste), hard core particles located at random in the bulk (aggregates), and a concentric soft shell surrounding each hard core particle (interfacial transition zone paste). However, this microstructural model is generic in nature and has also been applied to modelling air voids in concrete, macro-defect-free cements, and silica sol gels. Any system consisting of partially overlapping or totally non-overlapping spherical particles can be modelled using the developed computer programs, perhaps with some minor modifications. In addition to generating a representative 3-D microstructure, the programs can also be used to assess the percolation characteristics of the microstructure and estimate a diffusivity (or electrical or thermal conductivity) for the composite media. Complete program listings and example datafiles are provided in the appendices of this documentation and the software is also available for dowloading via anonymous ftp.

Citation

NIST Interagency/Internal Report (NISTIR) - 6265

Report Number

6265

NIST Pub Series

NIST Interagency/Internal Report (NISTIR)

Pub Type

NIST Pubs

Download Paper

Local Download

Keywords

building technology, computer modeling, concrete, diffusivity, hard core/soft shell, microstructure, percolation, simulation

Citation

Bentz, D. , Garboczi, E. and Snyder, K. (1999), A Hard Core/Soft Shell Microstructural Model for Studying Percolation and Transport in Three-Dimensional Composite Media, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=860162 (Accessed October 10, 2025)