Verification of Sustainable Asphalt Concrete through the Energy Dissipation

Abstract

The kinetic energy created in the asphalt concrete due to practicing dynamic loading is absorbed and consumed to retain the properties of the asphalt mixture through its flexibility; however, part of the energy is dissipated in the initiation of microcracking and other types of distresses. In this work, the influence of additives (fly ash and silica fumes) on controlling the energy dissipation of asphalt concrete mixtures was assessed. Beam specimens of asphalt mixture were obtained from the roller compacted slab samples and tested for fatigue under three constant strain levels by implementation of the four points bending beam. It was noticed that for fly ash treated mixture, the consumed time for energy dissipation decline by (75, and 97.5) % while the dissipated energy declines by (84.8, and 99.5) % when the constant strain level increases from (250 to 400 and 750) micro strain respectively. However, for silica fumes treated mixture, the energy dissipation declines by (3.3, and 95) % when the constant strain level rises from (250 to 400, and 750) micro strain respectively. It was noticed that the damage resistance as indicated by the increment in dissipated energy increases by (60, and 140) % when fly ash and silica fumes were implicated respectively. However, the silica fumes additive consumes the energy at lower time of 60 seconds than the case of control mixture. The fly ash additive exhibits no significant variation in consuming the energy when compared with the control mixture.