Rheological behavior of a low crystallinity polyolefin-modified asphalt binder for flexible pavements

An asphalt binder (PG 64?22) is modified with a crystallizable copolymer of polypropylene (PP) and polyethylene (PE) to enhance its ability resist rutting in flexible pavements during periods warm weather. After cooling binders from the mixing temperature at controlled rate 3 °C/min, their microstructure rheological behavior are characterized. The asphalts exhibit two-phase morphology droplets maltene-rich polymer phase less than 50 ?m size dispersed an asphaltene-rich, continuous phase. X-ray diffraction patterns optical birefringence microscopy indicate that PP/PE segregates matrix cooling, forming network interconnected, crystalline fibrils. At temperatures (50–80) °C, which issue pavements, addition substantially increases factor by 2–6, depending on concentration. (?20 0) 5 wt.% or modifier has minimal impact performance based both s -value m -value. -controlled, ?T c about 6.4 suggesting effective for reducing pavements.