Evaluating the Effect of Zycosoil on Moisture Damage of Hot-Mix Asphalt Using the Surface Energy Method

摘要

There are several approaches for improving adhesion and moisture sensitivity in asphalt mixtures, one of which is to coat the aggregate surface with a suitable agent to change the predominant electrical charges at the surface and reduce the surface energy of the aggregate. In this study, the effects of using Zycosoil as an antistripping additive on moisture susceptibility of asphalt mixtures has been evaluated by determining the mechanism that affects the adhesive bond between the aggregate and asphalt binder using the surface free energy (SFE) method and laboratory dynamic modulus test. The percentage of the aggregate surface exposed to water (P index) has also been calculated by using the measured SFE and dynamic modulus results, and evaluated as an index for the moisture susceptibility of mixtures. The results of the SFE method show that Zycosoil decrease the difference between the free energy of the adhesion of aggregate-asphalt binder in dry and wet conditions, and this difference is equal to the amount of energy released when stripping occurs. Coating of the aggregate surface with Zycosoil decreases this difference, and subsequently causes the mixture to be more resistant to moisture damage.