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Effect of Statistical Fluctuation, Finite Size Error, and Digital Resolution on the Phase Percolation and Transport Properties of the NIST Cement Hydration Model.


pdf icon Effect of Statistical Fluctuation, Finite Size Error, and Digital Resolution on the Phase Percolation and Transport Properties of the NIST Cement Hydration Model. (1256 K)
Garboczi, E. J.; Bentz, D. P.

Cement and Concrete Research, Vol. 31, No. 10, 1501-1514, October 2001.

Keywords:

cements; cement hydration; cellular automaton; statistical fluctuation; finite size error; digital resolution; particle size distribution; cement chemistry; percolation

Abstract:

The NIST cement hydration model starts with a three dimensional digital image of cement particles, and then uses cellular automaton rules to simulate the reaction of cement with water and the development of cement paste microstructure. This model is a model of a random process, using a fairly small periodic unit cell, and using a digital image with a certain resolution to represent the reality of continuum shapes. As such, it is potentially subject to statistical fluctuation, finite size error, and the effects of digital resolution. This paper evaluates the model in light of these potential sources of error, along with the effects of cement particle size distribution, w/c ratio, and cement chemistry, by focusing on the phase percolation and transport property predictions of the model. Statistical fluctuation and finite size error is shown to be of minor importance in the model. The effect of digital resolution is significant, however, but different from the case of a finite element or finite difference model. The "best" resolution is not necessarily the finest resolution, but must be chosen based on comparison with experiment and various physical length scales present in cement paste.