Investigation of recycled asphalt mixtures in Missouri: laboratory, field, and ILLI-TC modelling

This study investigates the lab and field performance of four asphalt mixtures placed in Missouri, USA, containing reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS). Laboratory tests including disk-shaped compact tension fracture (DC(T)), indirect tension (IDT) creep and strength, Illinois flexibility index (I-FIT), indirect tensile cracking test (IDEAL-CT), and the Hamburg wheel tracking test (HWTT) were conducted on field cores and plant-produced, lab-compacted (PPLC) samples. The DC(T), I-FIT, and IDEAL-CT tests showed that all of the mixtures exhibit brittle behaviour and have high cracking potential, while the HWTT indicated that rutting does not appear to be a concern with these mixes. Statistical analysis was performed to examine the capability of the performance tests investigated to distinguish between mixes. The DC(T) exhibited the best ability to distinguish between mixtures, while IDT strength displayed the least ability. Simulations using the ILLI-TC software were conducted to further explore the low temperature cracking behaviour of the mixes. Finally, field data collected using an automatic road analyzer (ARAN) was analyzed to further assess the laboratory performance tests.