Optimal Timing of Preventive Maintenance for Addressing Environmental Aging in Hot-Mix Asphalt Pavements Status: CompleteReport Date: 12/15/2014 Summary: Researchers investigated the proper timing of preventive maintenance by evaluating the relationship between asphalt material properties and aging in two roadway test sections: at the MnROAD pavement research facility and on Minnesota's Trunk Highway 56. TH 56 results suggested that to mitigate damage from environmental aging, sealing should occur within the first two years of the pavement's life. After that time, while some benefits may still be obtained from treatment, the damage from environmental aging may have already substantially occurred. The MnROAD test section did not confirm this finding, possibly because it had not yet aged enough to illustrate the benefit of early preventive maintenance. Final Deliverables: Report #2014-45 Technical Summary Related Materials: Related Research: