Aggregate properties affecting adhesive quality in asphalt mixtures

Asphalt-aggregate adhesion is a complex phenomenon influenced by properties from both materials. This work aims at stablishing the influence of aggregate’s chemistry, mixing temperature and surface texture over the quality of the asphalt-aggregate interface. To accomplish this goal, different asphalt-aggregates combinations were tested with a pull-off debonding test in which these properties of aggregates were changed accordingly. It was found out that SiO₂ content within aggregates promote moisture damage, whereas Fe₂O₃ and CaO contents seems to inhibit it. Low mixing temperatures when performing the initial asphalt-aggregate bonding were also related to low adhesive performance. Finally, aggregate surface texture did not seem to have an effect over the dry quality of the asphalt-aggregate interface but does seem to have a positive effect over its performance under moisture conditions.