Generally, dense graded asphalt concrete using modified asphalt, dense gap-graded asphalt concrete are applied for surface course and coarse graded asphalt concrete (for concrete slabs), guss asphalt mixtures are applied for binder course (for steel decks).

  W-mastic is brand name for Stone Mastic Asphalt (SMA). And there are two types, namely Type I and Type II. The features of this mixture is more water protective, flexible, rutting resistant, raveling resistant, durable, moreover easier to construct than guss asphalt mixtures because this mixture is constructed by ordinary pavers thus enabling lower construction cost.

[For Concrete slabs]   W-Mastic Type I which is more water protective is used for binder course and it function also as water protection layer.   Emulsified rubberized asphalt is applied for tack coat on concrete slabs at the rate of 0.4 liter per 1 m2.   In cases the depth of binder course is less than 30 mm, W-Mastic II (maximum aggregate size: 5 mm) is applied.   It is more effective to apply W-Mastic I for surface course too.
[For Steel Deck]   Shot blast grinding is applied to steel deck. And then melting type of rubber asphalt is applied as binder.   0.4 litre per 1 m2 of emulsified and rubberized asphalt is sprayed as tack coat.   In cases asphalt concrete using stiffer type of modified asphalt are applied, often cracks on beam are observed.   For surface course, sometimes dense graded asphalt concrete using softer modified asphalt is used as at the project of Honshu-Shikoku overseas bridge.