Is Seal Coating Counterproductive or Not?

SPONSOR:  MINNESOTA DEPARTMENT OF TRANSPORTATION

PI:  Zhanping You

While seal coating has been widely used as a cost effective strategy in asphalt pavement preservation, many cities in Minnesota have reported their concerns of the premature stripping of street pavements under seal coating. As a result, there is a growing number of local agencies that are choosing not to use seal coating. The Minnesota Department of Transportation (MnDOT) wants to know if this premature stripping is caused by seal coating. If yes, then what is the mechanism for this? Is seal coating counterproductive in cities in Minnesota? A hypothesis proposed that premature stripping is caused by the high air void pavement, which allows water to intrude and spread, and the low surface breathability, which traps water in the asphalt pavement.

This research will investigate this problem through literature review, field data collection and lab testing. The lab tests include permeability and surface breathability tests, effect of air voids on moisture susceptibility, and effect of seal coating on moisture susceptibility.

The objectives of this research are to: 1) find out the causes of premature stripping of street asphalt pavement under seal coats; 2) investigate possible solutions to address pavement stripping under seal coats; 3) provide recommendations for the preservative strategies of street pavements in Minnesota.

Zhanping You
Zhanping You