Dissipated Energy Analysis of Four-Point Bending Test on Asphalt Concretes made with Recycled Aggregates

The paper discusses the results of an experimental study and a theoretical analysis on the fatigue performance of asphalt concretes, evaluated by the four-point bending test, at 20\ub0C and 10 Hz. The laboratory investigation was conducted on five different base-binder bituminous mixtures, made with recycled aggregates, namely Reclaimed Asphalt Pavement aggregate (RAP) and Electric Arc Furnace (EAF) steel slag, up to 70% by weight of the aggregate. The fatigue tests were performed in stress and strain control mode, in order to describe completely the fatigue properties of the mixes. A dissipated energy method, based on the macro-structural damage condition of the mixtures, was used for the fatigue analysis. The damage curves, expressed in terms of the Plateau Value of the Ratio of Dissipated Energy Change, for both the stress and the strain control mode, were elaborated and statistically analyzed in order to unify the fatigue analysis. With respect to the control asphalt concrete, made exclusively with limestone aggregate, the mixes with RAP and EAF slag resulted characterized by improved fatigue properties and delayed macro-crack initiatio