Published in 2004
Because of the importance of having a good drainage mechanism built into a pavement structure to prevent premature failure, the Virginia Department of Transportation (VDOT) has used drainage layers under both portland cement concrete and asphalt concrete since the early 1990s. Unfortunately, these mixes have been rather difficult to place and durability has been a possible issue of concern. The purpose of this study was to design an improved asphalt drainage layer for one of the VDOT districts that eliminated the deficiencies of previous drainage layers. A 50-50 blend of No. 68 and No. 8 aggregates was chosen based on laboratory testing, and the mix was installed in a newly constructed flexible pavement with good results. The mix was easy to place and contained thick asphalt films that should contribute to a long service life. Based upon this success, a specification was drafted, and the mix was used in an additional project in the fall of 2003.
Last updated: November 28, 2023