Evaluation of reclaimed asphalt pavement incorporation in aspha-min modified warm mix asphalt

Abstract

Reclaimed Asphalt Pavement (RAP) can reduce the demand for virgin aggregates and binder in asphalt mixtures, but its performance depends on the behavior of aged binder-coated particles and their interaction with production temperature. This study evaluated RAP incorporation in Aspha-min modified Warm Mix Asphalt (WMA) and compared it with corresponding Hot Mix Asphalt (HMA) mixtures under local material and specification conditions. RAP was incorporated at 20%, 40%, and 60% replacement levels. The mixtures were assessed using volumetric properties, Marshall stability and flow, Indirect Tensile Strength (ITS), and Tensile Strength Ratio (TSR). A practical blending evaluation indicated very low RAP binder activation; therefore, RAP was treated mainly as a stiff coated aggregate, and the 60% RAP mixture was redesigned separately. Results showed that increasing RAP content increased Marshall stability and reduced flow, while air voids generally increased, particularly in WMA. ITS and TSR also improved with RAP content, and all RAP-incorporated mixtures satisfied the relevant wearing course criteria. The simplified environmental assessment showed increasing benefit with RAP content, reaching 54.95 MJ/t total energy saving and 3.98 kg CO2/t reduction for WMA with 60% RAP. The findings confirm that RAP can be incorporated in Aspha-min modified WMA when binder activity and volumetric control are properly considered.