Comparison of Performance Properties of Asphalt Mixtures Modified Using Polymerized Pellets and Polymer Modified Bitumen

Polymer modified asphalt binders have been used for years to produce asphalt mixes with improved resistance to rutting, fatigue cracking, and thermal cracking. Special equipment and technique, which may not be always available, are required to produce polymer modified binders with desired engineering properties. Recently, a new approach is introduced to facilitate the use of polymers in asphalt mixtures. Polymer-binder additive, with 40% Styrene Butadiene Styrene [SBS], produced in pellet form can be directly incorporated to the mix during production in asphalt plant without the need for any special equipment. Logistically, this new form of mix additive simplifies and expands the use of polymers even for small paving projects. However, due to the novelty of technology more research is required to assess its efficacy. In this paper stiffness, rutting, fatigue, and thermal cracking resistance properties of asphalt mixes modified with polymerized pellet are compared to the mixes containing unmodified and polymer modified binders. The effects of long-term oxidative aging on stiffness and strength of mixes were also evaluated. Result of this study showed that the polymerized pellet mix additive had similar effects as the SBS polymer modified binder in improving asphalt mix performance-related properties.