Applying asphalt binder modifier in reducing moisture-induced damage of asphalt mixtures

Abstract

In this study, it has been attempted to use thermodynamics theories and the surface free energy (SFE) method to evaluate the effect of anti-stripping additives on the asphalt binder cohesion and asphalt binder–aggregate adhesion under dry and wet conditions. Two types of aggregate, granite and limestone, AC 60–70 and two additives (a polar copolymer and an ethylene copolymer with mineral asphalt binder) used are among the materials used in this study. The results indicate that the use of both types of polymer has increased the cohesion of the asphalt binder and reduced failure in the asphalt binder film. The results show that the polar copolymer increases the basic components and decreases acidic component of the asphalt binder surface free energy that increases the adhesion with acidic aggregates that are susceptible to moisture-induced damage. Ethylene copolymer material also increased the asphalt binder surface free energy that strengthens the non-polar asphalt binder–aggregate bonds. Both polymer materials have reduced the separated free energy and increased the adhesion free energy that reduces the desire for the stripping process in the asphalt mixture. The results of mechanical tests also show that the use of polymeric additives has improved the asphalt mixtures strength against moisture-induced damage.