Evaluation of high percentage of alternative aggregates for the production of hot mix asphalt surface layers

In the last decades, recycling of hot mix asphalt (HMA) materials became one of the major issue concerning the world of pavement engineering. As required by Italian technical specifications, pavements surface layers must be produced using high-quality aggregates, in order to meet performance in terms of mechanical and anti-skid properties. Inevitably, the extraction of virgin mineral aggregates and their decreasing availability encourage the use of recycled alternatives, such as electric arc furnace steel slag and municipal solid waste. This study evaluates the possibility to implement recycled aggregates, and others sustainable solutions, in the production of HMA surface layers. In particular, eleven mixtures were produced combining the use of recycled aggregates to polymers obtained from plastic waste recycling and basalt fibres obtained from mineral deposit productions. Laboratory and field results confirmed the validity of the ecological solutions proposed in terms of fundamental properties for surface layers, such as fatigue resistance, rutting and skid resistance.