Cooling Time Requirements for Asphalt Pavement Repairs

In repairing asphalt pavements of busy airports or highways carrying heavy traffic, a common constraint encountered is tight time windows available for the repair work. A consideration is to provide sufficient cooling time before opening to traffic. Opening too soon to traffic with insufficient cooling time may lead to early damage to the repaired pavement. This is due to the relatively high temperatures in the asphalt layer as well as the interfacial bonding layer, resulting in insufficient strength in both layers not strong enough to resist heavy wheel loads. This paper applies a validated finite-element simulation model to analyze the time history of temperature cooling in a newly compacted asphalt pavement layer. The simulation model makes use of the thermodynamics and heat transfer theory to predict the temperature changes with time after a newly paved pavement section has been compacted. This information will enable the maintenance team to determine the appropriate time that the repaired pavement section can be opened to traffic. This paper analyzes two common thicknesses of pavement repairs, predicts time variations of temperature within the newly paved asphalt pavement materials for different weather conditions. A summary of the cooling time needed for each case of pavement repair under different weather conditions is presented. The results highlights that the commonly adopted practice of relying on the top surface temperature to open a newly repaired pavement section to traffic is inappropriate and may lead to early damages to the repaired section.