Field Trials of High-Modulus High-Binder-Content Base Layer Hot-Mix Asphalt Mixtures: Fid-Bau Portal

Field Trials of High-Modulus High-Binder-Content Base Layer Hot-Mix Asphalt Mixtures

B. K. Diefenderfer / G. W. Maupin

The purpose of this study was to document the field experience of the Virginia Department of Transportation (VDOT) in the use of high-modulus high-binder-content (HMHB) base layer hot-mix asphalt (HMA) mixtures. Information was gathered with regard to the construction of HMHB base mixtures at three field trial sites in Virginia, and laboratory tests were conducted on samples that were gathered before and during construction. The three locations were the sites of deep rehabilitation or new construction, and HMA base mixtures were used at designed asphalt content, designed asphalt content plus 0.4 percent additional asphalt, and/or designed asphalt content plus 0.8 percent additional asphalt. Two of the field trial locations had no construction-related issues; difficulties during compaction occurred at the third. Laboratory testing of materials collected from this location showed the mixture to have a low air void content, a high percentage of voids filled with asphalt, and a binder performance grade that was lower than expected. This was also the only location from which materials were collected for fatigue testing, the results of which did not show a clear relationship between binder content and fatigue life. It is thought that the mixture production and construction issues at this location were site specific and not generally indicative of a larger trend when HMHB mixtures are used.