Published in 1996
One of the most commonly used dense-graded aggregate mixes in Virginia is designated as Type 2lB. In an effort to improve drainage characteristics of the 21B material it was proposed to decrease the maximum allowable percentage of fines from 7% to 5% while retaining the existing percentage ranges for course particles. Prior to implementing this modification, the Virginia Department of Transportation (VDOT) conducted a series of laboratory tests to assess the potential impact of the revised material specifications. Samples of 21B aggregates produced by 19 quarries located throughout Virginia and North Carolina were analyzed. The results showed no statistically significant relationship between the percentage of times and the coefficient of permeability. It can be concluded that the proposed decrease in the maximum allowable percentage of fines from 7% to 5% would not result in a significant improvement in roadway drainage.
Last updated: December 17, 2023