Developed in Germany in the 1960’s. Now intensively used Worldwide.
Hot asphaltic paving mix (HMA) with high Coarse Aggregate Content coated by Asphalt-Filler mastic, to provide a Stone-Stone skeleton.
High VMA and high Bitumen content. Cellulose Fibers are added to prevent Bitumen drainage from the mix during production and hauling.
SMA provides a deformation & fatigue resistant, durable surface layer, suitable for sustainable heavy trafficked Roads and Airports.
The Current SMA Problem
The necessity to add the Cellulose Fibers creates serious problems:
- Double the mixing time due to low workability;
- Elevation of the mixing and compaction temperature;
- Elevation of the optimum Bitumen content;
- Elevation of the total cost of the mix (up to 60%);
- Generally a non-friendly mix to produce and lay;
- “Fibers serve no real purpose after the mix is compacted in-place” (NCAT pub. AAPTP 04-04, Feb. 2009)
A better SMA Bitumen stabilizer is timely needed