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This menu selection is used to create and store a PSD file which specifies the number of cement particles of each diameter to be placed in a starting 3-D microstructure. The output file created by this selection can be specified as input to Menu Selection 3) Generate an initial 3-D microstructure.
Figure 5: Form to specify and store a PSD.
The form (shown in Figure 5) to create a PSD file consists of a table listing the diameter, mass fraction, and number of particles, followed by two entries to specify the total number of particles or the water-to-cement ratio (w/c), respectively. The user may edit the mass fractions to match those obtained from one of the cements in the cements image database as discussed above. Then, they may either fix the number of particles and have the embedded JavaScript routine calculate the w/c, or fix the w/c with the number of particles being calculated. In addition, they may change any of the specific entries for the number of particles in the last column of the table. For example, the number of particles for all diameters larger than 41 µm could be manually set to zero. For the automatic calculation of the number of particles when a w/c is specified, it may not always be possible to match exactly the desired w/c ratio, as one too many large particles may result in a substantial change in the w/c. In this case, the user may manually set the mass fraction of these larger diameter particles to zero and repeat the automatic calculation by respecifying the desired w/c value. As a final entry, the user supplies the name of the file to be created (with an extension of .psd being automatically added by the VCCTL program).