General Principles and Some Theory

The principles of designing an aggregate mix and then the content of binder are presented in Figure 7.12. It is an illustration of a telescopic[37] method of creating SMA, which involves inserting consecutive elements into free space (air voids) in a compacted component of a larger size. In other words:

• A volume of fine aggregate is inserted into the air voids in the compacted coarse aggregate skeleton with the effect of increasing the air voids among the coarse aggregates (enlarging effect).

• A volume of filler particles is inserted into the air voids in the compacted fine aggregate.

• A volume of binder is introduced into the air voids in the compacted filler.

• The free space remaining after inserting all these elements produces the content of air voids in a compacted SMA.

Voids Enlarging effect

Filler

Binder + stabilizer

FIGURE 7.12 Placing consecutive elements of SMA in a mixture. (From Voskuilen,

Ideas for a volumetric mix design method for Stone Mastic Asphalt. Proceedings of the 6th International Conference Durable and Safe Road Pavements, Kielce [Poland], 2000. With permission.)

Filling the air voids with the subsequent elements has already been partially dem­onstrated and discussed when explaining the concept of air voids in a filler (see Chapter 3).

Determining the density of all the SMA components is the basis of the design activity because the Dutch method is a volumetric-type method.

Updated: 15 ноября, 2015 — 6:56 пп