By and large, the production of an SMA in contemporary asphalt plants does not present particular problems. The following are a few general tips about the production of SMA:
• SMA requires some production consistency with no breaks, stoppages, or similar “jerking” of the production process. Any alterations to the type of mixture being produced require adjustments of the batching device controls, the weight of mixture constituents for the mixer, and so on. Potentially more troublesome, any stoppages necessitate restarting the machine and beginning the production again.
• The moisture content of the aggregate leaving the dryer should not be higher than 0.5%, optimally less than 0.2% (USACE Handbook, 2000).
• When initial batching (cold feeders) limits the machine’s output, an additional batching device should be considered; bear in mind that coarse aggregates constitute more than 70% (m/m) of the mixture and may require more than one bin to feed that large a quantity.
• Due to the small amount of sand in an SMA, coarse aggregates passing through the dryer’s drum are exposed to more intense heating; therefore it is important to make sure that the asphalt mixture is not overheated.
