Influence of ageing conditions on the chemical property changes of asphalt binders

This study examines the influence of different ageing conditions on the commonly interested chemical properties of asphalt binders, including the oxygenated functional groups and Corbett fractions. Three ageing conditions were applied to five types of asphalt binders, which were tested at different time points during the ageing processes. Changes in chemical properties were analysed in order to understand the effects of binder type, time, and ageing conditions. Ageing conditions were found to affect the generated ageing products. This is manifested in both the changes in functional groups and Corbett fractions. Unexpected rise in saturates was found in asphalt binders aged in pressurised pure oxygen. Colloidal instability index indicates that some binders are more resistant to oxidative ageing than others, and sulphur appears to play an important role. Changes in chemical properties per unit increase in log dynamic viscosity are dependent on binder type and ageing conditions. The chemical indicators created by PAV ageing is closer to those created in more natural ageing conditions. However, the difference between PAV ageing and more natural ageing enlarges as PAV ageing time is extended.