Rheological and Mechanical Properties of HMA Containing Fly Ashes as Alternative Filler

This study defined the mechanical/volumetric properties and the environmental compatibility of bituminous mixtures containing fly ashes as alternative of traditional limestone filler. The research study is articulated in different steps as follows: (a) characterization of fly ashes according to EN 13043 Standard; (b) environmental compatibility analysis of mastics containing fly ashes by a leaching test; (c) stiffness evaluation of the mastics containing limestone and fly ash filler by static testing, as Delta Ring and Ball Test, and dynamic testing, as Frequency Sweep Test; (d) mechanical and volumetric characterization of asphalt concrete containing fly ashes and limestone filler starting from a phase of mix design of hot mix asphalt mixtures. The characteristics of stiffness of the bituminous mixtures has been evaluated on the optimum HMA through a dynamic test with a sinusoidal load. Then, the ability of two different HMA to endure a permanent deformation was evaluated by a Repeated Load Axial Test. The results has shown that mixtures of Hot Mix Asphalt with flying ashes as filler, compared to Hot Mix Asphalt containing limestone filler, is preferred in terms of mechanical performances and relevant environmental compatibility evaluated with the leaching test.