The “job mix”, or the “design mix” as it is also sometimes called, refers to the ratio of bituminous binder to aggregates of varying sizes as outlined by the job’s specification. Because of the integration of dissimilar components, in this case, a hydrocarbon with stony matter, there exists the tendency for the entire mixture to lose its homogeneity, or breakdown. The inclusion of Asbuton to the mixture presents inorganic matter that is evenly distributed in such a way as to reduce the natural tendency of the mix to breakdown, or become prematurely unstable.

Due to the hardness of Asbuton (possessing a penetration of between 0 and 5), its softening point is naturally higher (70ºC) than soluble bitumen; therefore, its tendency to react to imposed forces (heat, pressure) is deferred significantly. This augurs well for any design mix, since it is an indicator that an Asbuton paving would be resilient to extreme temperatures.

Strain, being an engineering materials phenomenon defined by the elongation of a material as a ratio to its natural length due to applied tension, the ability of a Asbuton-blended mix to resist cracking under low temperatures is yet another performance-related characteristic. This allows it to yield incomparable results over a wide spectrum of extreme conditions. Despite its hardness, Asbuton outperforms the strain resistance of refinery bitumen by 28% at –10ºC. Source: Graph # 3, performance at low temperature, “Asphalt of Buton; A unique naturally occurring bitumen binder for improving the performance of asphalt pavements in roads, airports, tunnels and similar heavy duty sites.”

Pavements are subject to the harshest of conditions that include extreme temperatures, sharp temperature gradients, and heavy loads, promoting unwanted compression, shear and other mechanical drawbacks. Many of these manifest themselves as cracks in the surface, which are unsightly at best. The worst of these continue for such length as to eventually result in a total divorce of one part of the roadway from the other. As a consequence of improved mix stability, the incidence of these is either reduced or negated by the use of Asbuton.

Being an amalgamation of mainly aggregate and polymer-based binders with optional or recommended additives, a pavement’s entire section is always under a series of varying stresses. It is the occurrence of abrasion and the direct ultraviolet exposure that can result in loosening and eventual dispersion of the surface, for which, the higher quantities of maltenes promote binding capabilities and therefore suppresses the likeliness of surface breakup.

As a result of its higher specific gravity (up to 40% more than conventional, straight-run bitumen), Asbuton is remarkably resistant to fatigue in several forms, including compression and shear. Its higher density encourages a reduced tendency for inorganic matter movement and hence, higher fatigue-resistance.

The costs associated with downtime arising out of routine or remedial maintenance is a woe of even many a first class paving, which Asbuton is never purported to eradicate, but rather, reduce tremendously. Due to longitudinal shear, surface shear, daily positive and negative temperature gradients and other natural and subjective pressures, the asphalt’s entire section is eventually compromised to result in failure that warrants routine maintenance, and sometimes unforeseen costs. The use of Asbuton automatically reduces the maintenance effort sometimes by as much as 70%, quite often making it an eventual lower-costing alternative that many other modifiers.

This being the flagship of Asbuton characteristics, high speed and heavy duty users know of the virtue of anti-skid performance related to safety. Because better coatability is achieved in using a Asbuton binder over a soluble binder or other modified binder, the surface of the aggregate, as well as the force of cohesion between them, is more ‘polish-resistant’, allowing for a surface that is yields better tire to asphalt traction, and thus, far less tendency to skid.

Low temperatures and rain always present a problem for the smooth and easy handling of many road-surfacing applications. For hot mix pavements, this is an increased issue since the preferred temperature of laying the asphalt lies within a reasonably close tolerance. Although bad weather conditions only serve to promote the counterproductive environment of cooling, the heat-retention properties of Asbuton tend to counteract the urgency of any undesirable cooling, making it easier to handle in bad weather as a result of the material staying in its loose, mixed form longer.

As a testament to its affinity for binders, Asbuton can be mixed with all known polymers and polymer-related bituminous compounds. Being essentially a hydrocarbon that is chemically bound to interlocked inorganic matter, Asbuton resists the tendency for separation and sedimentation of other non-Asbuton binders, and this is what has enabled Asbuton to be used in 31 different countries around the world, each with equal success. In its native origin of Buton, it is blended with 180-200 penetration bitumen in measured proportions to produce a superior blend of 60-70 penetration Asbuton that is used on highways, airports and marine terminals.