Recycling Techniques and Environmental Issues relating to the Widening of an High Traffic Volume Italian Motorway

On the last few decades, the use of recycled materials has become important because of the limited availability of good aggregates and the difficulties and excessive disposal costs for milled materials. This study provides an environmental evaluation of a specific rehabilitation project involving several recycling techniques on one of the main Italian motorways. Three rehabilitation options are evaluated and compared in terms of their environmental impact, with particular emphasis on the construction of the subbase course. In the end, the definitive design involved different recycling techniques, including cold in-place recycling (CIPR) with bituminous emulsion and cement for the subbase layer, stabilization of the soil with lime for the embankment, the use of reclaimed asphalt in the production of hot mix asphalt, and the use of crushed cement concrete for the cement treated layers. All of these recycling methods allow the saving of the virgin aggregates, and a reduction in materials transportation and pollutant emissions coming from both the production plant and the means of transport.