Estimation of the surface free energy and moisture susceptibility of asphalt mastic and aggregate system containing salt storage additive

The moisture susceptibility of asphalt mixtures containing salt storage additive is a focus. The objective of this study was to characterize adhesion characteristic of asphalt-aggregate system containing salt storage additive. The contact angle test and boiling water test were carried out to obtain the contact characteristics and stripping behaviour of them. The results indicate that the contact angle values of asphalt mastic increased with the increment of salt storage additive resulting in poor wettability. And the surface free energy values of asphalt mastic slightly reduced with increased salt storage additive, and were remarkably less than that of water leading to bad affinity with stone under moisture condition. The adhesion works under moisture condition mainly depended on stone lithology, and had good negative correlation with the stripping area ratio values from boiling water test.