Evaluation of Effectiveness of Cleaning on In Situ Permeability Restoration of Open-Graded Friction Course

Abstract

The open-graded friction course (OGFC) with a high air void has been used due to its provided benefits; however, the clogging issue becomes a challenge for in-service pavement with an OGFC overlay. This study relied on an airport expressway that has been in service for 9 years and evaluated the long-term permeability performance of the OGFC layer. A cleaning vehicle equipped with a high-pressure water and vacuum system was used to clean the OGFC pavement, and the effect of cleaning on the permeability restoration of OGFC pavement was evaluated for different traffic lanes and locations. One-way ANOVA statistical analysis was further conducted. The test results showed that the emergency lane on the bridge exhibited the worst permeability and the most severe clogging, whereas the traffic lane with higher vehicle speed showed better permeability than that with lower vehicle speed. No significant difference in permeability was found between the nonwheel path and wheel path. A cleaning vehicle with a capacity for flushing and vacuuming can effectively clear out the clogged materials in an OGFC overlay and thus improves permeability. However, the permeability restoration after cleaning is different at different locations. Overall, the permeability restoration at the nonwheel path is higher than that at the wheel path. Three or four rounds of cleaning at the emergency traffic lane where the most severe clogging occurs are suggested.