A fixed coarse aggregate content was assumed in Part II of the design example. We explored the subdividing of the coarse aggregate fraction and its subsequent consequences. We saw that the shape of the gradation curve in the area larger than 2 mm has great significance on the properties of an SMA mixture. Thus, by increasing the predominance of very coarse grains, we increase the following:
• Resistance to permanent deformation (in general, but not in all cases)
• The content of VMA
• The binder quantity
• The permeability of a course
A final remark: setting up the skeleton using only the coarsest particles—namely, creating a single-sized mixture—will bring about possible problems with the interlocking of the skeleton grains; contrary to expectations, such a course will be of poor quality.
