Hot Mix Asphalt Mix Design Evaluation Using the Corelok Vacuum-Sealing Device

The bulk specific gravity $\left({\mathrm{G}}_{\mathrm{mb}}\right)$ of compacted hot-mix asphalt (HMA) specimens is the basis for volumetric property calculations during mix design and quality control and assurance. For many years, ${\mathrm{G}}_{\mathrm{mb}}$ measurement has been accomplished by water-displacement procedures. Water displacement yields accurate ${\mathrm{G}}_{\mathrm{mb}}$ for most conventional dense-graded mixes, but ${\mathrm{G}}_{\mathrm{mb}}$ measurement errors using water displacement have been observed for coarser-graded mixes. Recently, vacuum-sealing technology, using the Corelok vacuum-sealing device has been shown to yield more accurate ${\mathrm{G}}_{\mathrm{mb}}$ values. This study’s objectives were to illustrate ${\mathrm{G}}_{\mathrm{mb}}$ differences between water-displacement and Corelok procedures and resulting changes in volumetric properties and design asphalt contents. Results indicate significant ${\mathrm{G}}_{\mathrm{mb}}$ differences between Corelok and water-displacement procedures, with the Corelok procedure yielding slightly higher ${\mathrm{G}}_{\mathrm{mb}}$ values, resulting in an average increase in design asphalt content and voids in the mineral aggregate of 0.29 and 0.64%, respectively, relative to water-displacement procedures.