An experimental procedure to determine the surface area of fine aggregate particles in fine aggregate matrix mixtures: Development and validation

•Laser granulometer can be used to obtain fine aggregate specific surface area.•Fillers can present a high variability of the specific surface area.•The asphalt binder film thickness of FAM is mainly from 0.5 μm to 30 μm.•The aggregate specific surface area procedure was validated using images acquired in a scanning electron microscope. The specific surface area (SA) of aggregates is a key parameter required to properly design fine aggregate matrices (FAM) based on the volumetric characteristics of corresponding asphalt concrete mixtures. However, SA is often determined based on procedures that adopt simplifying assumptions which may compromise the accuracy of this parameter. This study presents an experimental protocol to determine the SA of FAMs employing the laser diffraction technique. The aggregate SAs were combined with binder film thickness measurements determined with a digital analysis of images obtained in a scanning electron microscope and used to predict the binder content of the FAMs. The comparison between the predicted and the binder content actually adopted in the laboratory demonstrated that the proposed protocol provided reliable results to be incorporated into volumetric-based FAM design procedures.