Chemical and mechanical changes in asphalt binder due to moisture conditioning

This study evaluates the effects of moisture conditioning on changes in chemical composition and mechanical properties of asphalt binder. Moisture conditioning is conducted using the AASHTO T 283 procedure and the recently developed moisture-induced sensitivity testing (MIST) device. Chemical analysis is performed using the Fourier transform infrared device and the mechanical testing is performed by a dynamic shear rheometer. Results show that ageing as well as other chemical changes occurred during moisture conditioning. Changes in binder fatigue life and damaged modulus are observed. Undamaged modulus and cohesive damage due to moisture conditioning were synthesised from this damaged modulus. It is found that undamaged moduli for both MIST- and T283-conditioned samples are almost the same; however more damage occurs in MIST-conditioned samples. Two regression models were developed to correlate physical properties with chemical changes.