Conserving existing road pavements against aging: A new assessment method and evaluation of different techniques

Asphalt pavement is an important type of transport asset. Driven by traffic loading and aging-induced material deterioration, asphalt pavements are in bad condition in many places. Severely degraded pavements are often demolished and sometimes recycled. Alternatively, preventive maintenance can be applied to conserve the asphalt pavements. This would result in savings on costs, energy, resources and help mitigate negative environmental impacts. However, effective methods to evaluate the anti-aging performance of the preventative maintenance techniques are currently lacking. This study evaluated the feasibility of using the oxygen diffusion coefficient (Ds) of asphalt mixtures to quantitatively assess the oxygen-retarding efficiency of preventive maintenance techniques by examining the relationship between Ds and aging in surface-treated asphalt mixtures. Ds is found to be a very useful indicator to quantitatively represent the anti-aging performance of the preventive maintenance techniques. It is recommended to be used in future asphalt pavement conservation practices.