1370673 - Effect of blending conditions and polymer properties on the performance of polyethylene-modified asphalt binders and mixtures

In the production of polyethylene (PE) modified asphalt, the compatibility between asphalt binder and PE depends on a number of factors including binder source, PE properties, use of other compatibilizers, and blending conditions. However, the major challenge is phase separation due to the non-polar nature of polyethylene. The main objective of this study is to evaluate the performance of asphalt binders and mixtures modified with three PE sources: virgin low-density polyethylene (LDPE) pellets, recycled polyethylene (RPE) pellets, and post-consumer waste (PCW) polyethylene film. The study also evaluates the effect of various compatibilizers and mixing processes on improving the stability (i.e. reducing separation) of the PE-modified binders. The compatibilizers used in this study are elastomer (styrene-butadiene-styrene), reactive terpolymer (elvaloy), and cross-linking agents (CLAs) like sulfur and polyphosphoric acid (PPA). It was found that separation can be reduced to low levels that meet specifications by optimizing the mixing process along with the choice of a compatibilizer. The Hamburg rutting test has shown that PE-modified mixtures have better rutting resistance in comparison with control, unmodified mixtures. However, the IDEAL-CT test showed a reduction in fracture resistance, which can be countered by adjusting the mixture design and proper selection of the location of the mixture within the pavement structure.