SMOOTH DOBLE DRUM USED IN ASPHALT COMPACTION:

COMPACTION CHARACTERISTICS OF ASPHALT:

FUNDAMENTALS

After laying asphalt layers must be compacted to achieve stability and reduce air voids to minimum, in order to avoid subsequent compaction or deformation under the influence of traffic loads and climatic conditions, which could impair the suitability of traffic areas or reduce their durability. Purpose of the compaction of asphalt layers is therefore the production of the air void content in asphalt mixer that is adapted to the required binder content.

               The required compaction work depends on the properties and workability of the asphalt mixture, as well as the thickness of the asphalt layer to be compacted. The compaction effect is influenced by the laying conditions as well as by the effectiveness of compaction machine and compaction technique. The compaction characteristics differ considerably in dependence on composition and the temperature dependent characteristic of increasing the density of asphalt under the influence of defined compaction work. In dependence on the deformation resistance a differentiation between easy and difficult to compact mixtures can generally be made.

               Easily compactible mixtures show a high increase in density right at the beginning of the compaction process, followed by an early end of this increase. Relatively low density increase rates from the beginning right to the end of the compaction process are characteristic for difficult to compact mixtures, whereby a considerably higher number or more powerful compaction passes and a longer work process is required. In both cases the increase in density decreases the course of the compaction process. Remember that the leaflet on the compaction of rolled asphalt mixtures is described by an exponential formulation, derived from bulk densities.