Characterization of the air void content of fine aggregate matrices within asphalt concrete mixtures

Abstract Fine aggregate matrix (FAM) has been regarded as a key constituent of asphalt mixtures. Several attempts focusing on the proper fabrication and characterization of FAM have been pursued in the last decades. However, there are still some limitations that require further investigations. One of those shortcomings is how to define the air void (AV) content to produce isolated FAM testing specimens that are representative of those comprising asphalt concrete (AC) mixtures. This paper suggests a criterion to select the AV content to fabricate isolated FAM testing specimens based on a comprehensive examination of this AC phase using X-ray micro-computed tomography tests and digital image processing with artificial intelligence techniques. The results indicate that the proposed procedure can provide key insights into the volumetric characteristics of FAM mixtures. This may in turn contribute with the improvement of FAM design protocols and result in more accurate characterizations of the behavior of this relevant constituent of asphalt mixtures, where relevant damage phenomena occur.