The effect of prolonged storage time on asphalt rubber binder properties

This study wants to provide fundamental understanding of prolonged storage time on asphalt rubber bin- der properties by performing an investigation on the variation of conventional properties, rheology and morphology of four asphalt rubbers maintained at 180 C in low shear for different digestion/storage times up to 48 h. The analysed asphalt rubbers were manufactured by combining two different asphalt binder grades, pen 35/50 and pen 50/70, with both cryogenic and ambient crumb rubber. Results have shown that keeping asphalt rubber agitated at the above mentioned processing conditions, up to 48 h, is significantly detrimental when an ambient crumb rubber is used, while it seems not to negatively affect the asphalt rubber produced with cryogenic rubber crumbs. Instead, no remarkable change is recorded when asphalt rubbers are produced with the same rubber type and by changing the base asphalt binders, namely pen 35/50 and pen 50/70.