Performance grading of extracted and recovered asphalt cements

Binder extracted and recovered from pavement core samples at two different locations from 18 contracts showed small differences within contracts, well within the minor borderline acceptance criteria. Serious discrepancies were found between original tank sampled asphalt binder and material recovered from pavement cores. Regular BBR grades for recovered materials were on average 2.7 °C in deficit, which is considered high for 3-5 years of service. EBBR grades were on average 7.6 °C in deficit (range 3 °C to 17.3 °C). Equilibrium grades, after 72 h of conditioning, correlated well with temperatures where the phase angle reached 30° after minimal conditioning, suggesting that a limit on phase angle may provide a practical quality assurance measure.