Evaluation of Permeability of Superpave Mixes in Maine

摘要

This study was carried out to evaluate the permeability of Superpave mixes used211u001eby the Maine Department of Transportation, and determine the effect of voids, 211u001egradation and lift thickness on permeability. A field parameter was developed on 211u001ethe basis of the National Center for Asphalt Technology field permeameter, and 211u001ewas used for testing projects with 9.5 mm, fine and coarse, 12.5 mm coarse, 19 mm 211u001ecoarse, and 25 mm coarse graded mixes. Testing of cores taken from location of 211u001efield testing were also conducted in the laboratory according to Florida 211u001eDepartment of Transportation method. Samples of loose mix obtained during 211u001econstruction were also compacted to different thickness in the laboratory, prior 211u001eto permeability testing. Results from permeability tests indicated that mixes 211u001ewith different gradations and nominal maximum aggregate size have significant 211u001eincrease in permeability at different voids in total mix content. All of the 211u001emixes tested in this project showed permeability below critical permeability at 211u001eor below 5 percent in place construction voids. Hence, the average specified 5 211u001epercent construction voids in total mix or 95 percent of theoretical maximum 211u001edensity seems to be justified for Superpave coarse graded mixes used by the Maine 211u001eDepartment of Transportation.