STONE MASTIC ASPHALT (SMA) ADDITIVE PURE CELLULOSE FIBER PELLETS
Stone Mastic Asphalt (SMA), was developed in Germany in the 1960s with the first SMA pavements being placed in 1968. It provides a deformation-resistant, durable surfacing material, suitable for heavily trafficked roads.
SMA has a high coarse aggregate content that interlocks to form a stone skeleton that resists permanent deformation. The stone skeleton is filled with a mastic of bitumen and filler to which fibres are added to provide adequate stability of bitumen and to prevent drainage of binder during transport and placement. Typical SMA composition consists of 70−80% coarse aggregate, 8−12% filler, 6.0−7.0% binder, and 0.3 per cent fibre stabilizing additive.
Addition of a small quantity of cellulose or mineral fibre prevents drainage of bitumen during transport and placement.
Stone mastic asphalt (SMA) is a material designed specifically for making top layers on roads with high traffic of transport.
The specificity of SMA concrete composition and structure implies the mandatory presence of hard cuboid-shape rubble, "voluminous" bitumen and a small amount of stabilizing (usually fibre) additive, for the disperse reinforcing of a binder, as main structural components. Empirically, the best stabilizing effect is shown by specially prepared natural cellulosic fibres. Based on extensive research and trials, we have selected most suitable natural fibre and the test results enumerated in this document reflects the exceptional quality of the final product.
STABILIZER ADDITIVE
One of the main factors, influencing the structure-formation processes of SMA and ensuring the quality of road pavement, is the interaction of bitumen with the (SA) surface. The strong adhesion ensures the high physical-mechanical properties and durability of material.
The differences of surface properties of fibrous materials substantially affect the nature of sorption processes at the interaction with bitumen. Natural cellulose material having a high sorption capacity is the first step to creating (SMA) with the desired properties, resulting in SMA concrete of high quality.
Pelletized cellulose fibers shall be utilized. The dosage rate for cellulose fibres is minimum by weight (on loose fibre basis) of the total mix. The dosage rate does not exceed 0.3 % when the tested in accordance with ASTM D 6390.
