Stone mastic asphalt is defined as a gap-graded asphalt mixture that has bitumen as a binder, and is composed of a coarse crushed aggregate skeleton bound with a mastic mortar.
The standard defines two types of recipes (job mix formulae [JMF]):
• Input target composition—this is the determined composition of the mixture given through listing its constituent materials, the gradation curve, and the percentage content of binder added to the mixture; this formula is the result of laboratory validation of the mixture.
• Output target composition—this is the determined composition of the mixture given through listing its constituent materials, the midpoint gradation, and the percentage of soluble binder content in the mixture, which are obtained as results of the composition analysis (extraction) of a produced mixture; usually this formula is the result of production validation of the mixture.
An additive is defined as a constituent material supplemented to the mixture in small amounts, (e. g., organic or nonorganic fibers and polymers added to enhance mechanical properties, workability, or the color of the mixture).
