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Filtering of random noise particle image

Once a 3-D image incorporating the desired particle size distribution has been created, the next step is to introduce the appropriate phase volume fractions, phase surface area fractions, and correlation structure into the initially monophase particles. This process is accomplished in a series of steps using one Fortran and two C programs. The Fortran program, rand3d.f (listing provided in Appendix B), is used to introduce the correct phase volume fraction and the correlation structure measured on the 2-D SEM image into the 3-D cement particle image. Starting with an image of random Gaussian noise, generated using the Box-Muller method [12], the measured autocorrelation function for the phase(s) of interest is used to filter the image, introducing the appropriate correlation structure. Each time this program is executed, the user must specify what phase is to be subdivided into two phases and the value to be assigned to the new phase. A typical sequence is to separate the cement into silicates and aluminates, separate the silicates into C₃S and C₂S, and separate the aluminates into C₃A and C₄AF, as illustrated in Fig. 4.

To use rand3d.f, the user must input:

• a random number seed (negative integer),
• the initial phase ID to be subdivided into two phases,
• the phase ID for the second (new) phase,
• the name of the file containing the current 3-D microstructure to be processed,
• the name of the file containing the correlation data for the phase(s) of interest, and
• the phase volume fraction (0.0 to 1.0) of the initial phase which is to retain its original phase value.

Next: Correction of hydraulic Up: Two-dimensional to Three-dimensional Previous: Generation of spherical