Developing critical field permeability and pavement density values for coarse-graded superpave pavements

L Cooley Jr, ER Brown… - Transportation research …, 2001 - journals.sagepub.com
L Cooley Jr, ER Brown, S Maghsoodloo
Transportation research record, 2001journals.sagepub.com
Within the hot-mix asphalt (HMA) community, it is generally accepted that the proper
compaction of HMA is vital for a stable and durable pavement. Low in-place air voids have
been shown to lead to rutting and shoving, whereas high in-place air voids have been
shown to reduce a pavement's durability through moisture damage and excessive oxidation
of the asphalt binder. Recent research has suggested that coarse-graded Superpave-
designed mixes are more permeable than conventionally designed pavements at a given air …
Within the hot-mix asphalt (HMA) community, it is generally accepted that the proper compaction of HMA is vital for a stable and durable pavement. Low in-place air voids have been shown to lead to rutting and shoving, whereas high in-place air voids have been shown to reduce a pavement’s durability through moisture damage and excessive oxidation of the asphalt binder. Recent research has suggested that coarse-graded Superpave-designed mixes are more permeable than conventionally designed pavements at a given air void content. This higher permeability can lead to durability problems. The pavement density at which coarse-graded Superpave mixes become permeable was evaluated by using a field permeability device. On the basis of the data collected, 9.5- and 12.5-mm nominal maximum aggregate size (NMAS) mixtures become excessively permeable at approximately 7.7 percent in-place air voids, which corresponded to a field permeability value of 100 × 10−5 cm/s. Mixtures having a 19.0-mm NMAS became permeable at 5.5 percent in-place air voids, which provided a field permeability value of 120 × 10−5 cm/s. Coarse-graded mixes having an NMAS of 25.0 mm became permeable at 4.4 percent air voids, which corresponded to a field permeability value of 150 • 10−5 cm/s.
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