Laboratory investigation and in-plant production validation of dense-graded warm mixtures with reclaimed asphalt

Nowadays, many researchers are focused on finding performance-effective and sustaina-ble alternatives to traditional hot mix asphalt (HMA) for paving applications. An eco-friendly and promising solution seems to be the warm mix asphalt (WMA) technology ap-plied to mixtures containing high reclaimed asphalt (RA) percentages due to the well-proven environmental and economic advantages, in addition to healthier working condi-tions. However, increasing RA percentages in WMAs could cause some disadvantages in workability and in-service performance, especially on roads with high volume of heavy traffic. To this regard, this research describes a laboratory investigation for the optimiza-tion of WMAs with 45% RA for base course and subsequent large-scale production vali-dation, to verify their possible use on the Italian motorway network. The experimental in-vestigation on both laboratory and in-plant WMA highlights successful volumetric and mechanical properties according to the current Italian motorway technical specification. Moreover, the qualification of in-plant mixture demonstrates the technical feasibility of production on a large scale by WMA technology without penalizing mixture performance.