Fat Spots of Mastic with Segregation
An area with a definite shortage of mastic adjacent to the fat spot (visibly porous) is a clear sign that this is a case of an SMA segregation—namely, separating the coarse aggregates from the mastic. If the quantities of all the ingredients have been properly selected, the high accumulation of one component in one location will result in a reduced quantity of that component in another. When an excess of mastic (fat spot) appears somewhere, the coarse aggregate content rises elsewhere, so the total sum of the components remains constant. Figure 11.2 presents a classic fat spot in a segregated SMA mixture. Figure 11.3 shows the difference between fat spot and adjacent porous section and a close-up of the mastic-rich area.
It is worth emphasizing that such segregation may happen for one ...
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