Low temperature performance of laboratory produced asphalt rubber (AR) mixes containing polyoctenamer

Abstract

The use of the additive polyoctenamer (PO) in asphalt rubber (AR) binders helps to improve their storage stability and to reduce their stickiness and tackiness, while not affecting the low temperature performance of the AR binders and mixes. The objective of this paper was to determine if the use of PO had any impact over the low temperature performance of laboratory mixes produced with AR binders that were also laboratory produced. The low temperature performance of the laboratory produced asphalt rubber (AR) mixes were evaluated by means of the semicircular bend geometry test, utilizing two types of ground tire rubber (ambient and cryogenic) at two different percentages of polyoctenamer (PO). Stiffness, fracture toughness and fracture energy for the mixes were obtained in order to statistically evaluate how the variables influence their low temperature performance. Overall, the laboratory test results indicate that the use of PO at the dosage utilized and the rubber types at the percentage employed will not adversely impact the low temperature performance of AR mixes; furthermore the use of PO can increase the fracture toughness of AR mixes, making the pavements less brittle at lower temperatures.