ABSTRACT
Moisture sensitivity is one of the common distresses in flexible pavements due to the deteriorating effect of water on adhesion of bitumen-aggregate and cohesion of mastic. In the present study, the effect of the styrene–ethylene–butylene–styrene as bitumen modifier was examined on the moisture damage potential of control and modified asphalt mixtures using thermodynamic and mechanical methods. The results of this study indicated that the modified asphalt mixtures have significantly better resistance than the control samples. In addition, the results of the thermodynamic parameters showed that changes in the surface-free energy components of the modified bitumen have improved the adhesion of these bitumens to high silica aggregates that are susceptible to moisture. Moreover, the use of styrene–ethylene–butylene–styrene increases the surface-free energy of mastic film, which also increases the resistance to cohesion failure. Furthermore, the results of the amount of energy released during the stripping event show that the use of bitumen modifying polymer additive has reduced the amount of de-bonding energy. This indicates that the tendency for bitumen to detach from the aggregate surface in the presence of water has decreased from the thermodynamics view.
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Disclosure statement
The authors declare that they have no conflict of interest.