Asphalt Permeability Testing Between Laboratories

About the report:

Problems with water penetrating into pavement were observed with the early coarse asphalt Superpave mixtures. There was justified concern that water would cause early deterioration; therefore, an effort was made to investigate the permeability problem and correct it. After an initial investigation revealed excessive permeability in many newly constructed Superpave pavements, the Virginia Department of Transportation's (VDOT) Materials Division decided that the potential permeability of mixtures should be determined during the mixture design phase prior to the start of construction. A technique of performing regressions of air voids and permeability with specimens prepared and tested in the laboratory was developed and refined at the Virginia Transportation Research Council. This investigation examined how well different labs agreed in two phases: one in which two VDOT laboratories participated and one in which contractors and VDOT laboratories participated. There was general agreement between laboratories in determining the acceptability of field samples of mixtures with regard to permeability. Potential difficulties and solutions in specimen preparation and regression analysis were discussed. The technique is currently being implemented by VDOT as a mixture design tool. It is estimated that the elimination of permeable mixtures that are not durable will save VDOT as much as $350,000 annually.

Authors