The use of non-conventional fillers in asphalt mixtures for wearing course

The choice of a filler for the production of asphalt mixtures for road pavements is the synthesis of a careful analysis of various performance aspects. In particular, filler, for its fineness and chemical composition, plays an essential role for obtaining compact and mechanically suitable, but that can ensure the maintenance of these requirements over time, asphalt mixtures. Compared to mineral fillers produced by milling lithic material or by recovering dust from filters of plants intended for the processing and the production of stone aggregates, some fillers derived from the industrial world and also from the related by-products could be usefully considered among those products that a designer can select, for local availability, process economy and improvement of expected performance. Paper presented a comparison between a traditional filler (limestone powder) and two non-conventional fillers (cement and coal combustion fly ash) in order to supply to asphalt mix designers the potential of consider the latter materials, even in mixtures for road surface layers, characterized by high filler content, subjected to road traffic and different environmental conditions.