Feasibility of Using Selected and Mixed Recycled Aggregates from Construction and Demolition Waste in Unbound Pavement Layers

The proper use of the natural resources is one of the fundamental pillars for the sustainable development required to current society. Construction and demolition (C&D) wastes have been considered as a priority stream because of the large amounts that are generated and their high potential for reuse and recycling. Despite their high potential, reuse and recycling rates vary widely across countries. Recycled C&D materials have been increasingly used as recycled aggregates in pavement base and subbase layers and other road construction applications. However, most of the research studies were carried out on selected recycled aggregates (recycled concrete aggregate, crushed brick or reclaimed asphalt pavement) not always available in quantities for full-scale use. This paper presents the laboratory characterization of two recycled aggregates coming from C&D waste (a non-selected (mixed) recycled aggregate and a selected recycled aggregate) to evaluate whether they meet the technical requirements established in Portuguese specifications, which would enable their application in unpaved rural and forest roads and embankments and capping layers of other transport infrastructures. A series of relevant physical, mechanical and chemical properties are evaluated, and the fulfilment of the requirements is subsequently discussed.