Only constituents with an established suitability are allowed to be used for SMA mixtures. The established suitability means meeting the material requirements of the following:
• A European standard
• A European technical approval (ETA)
• A documented, positive experience with a specific kind of material in the past in which the reference documents confirm the suitability of the material (e. g., test results combined with observations in places of performance)
14.4.1 Binders
Road (paving grade) binder according to EN 12591 and polymer modified binder according to EN 14023 have been used in SMAs. SMA mixtures containing chemically modified binders, which are not classified by the standard EN 14023, are not covered by the clauses of the standard EN 13108-5. Natural asphalts according to EN 13108-4:2005, Annex B, may be added.
Road binders after EN 12591 are categorized on the basis of penetration at 25°C and have been incorporated in SMAs. When using them, a binder from the series 30/45 to 330/430 should be selected. This is a very wide range of bitumens (from hard to very soft ones) intended to allow for a wide variety of possible applications depending on local conditions (e. g., climate, traffic loads). In reality, it is for the most part a choice between 50/70 and 70/100.
