HBP Pilot Void Acceptance Projects Completed in 1993-1996

摘要

In 1993, CDOT recognized that specifying HBP volumetric properties would likelyprovide superior pavements. A long range goal was set for acceptance to be based on voids properties (VA). Beginning in 1993, a series of VA pilot projects were let to contract; by the end of 1996, nine had been completed. Six had conventional mix designs. The last three were designed using Superpave technology. The data for the nine VA projects is summarized and compared with data from concurrent CDOT projects under Quality Level Analysis (QLA). The quality levels and pay factors for VA projects are somewhat to considerably less than for the concurrent QLA projects. This is attributed to (1) changes in specifications, test methods, and test equipment made during the pilot program, (2) large sampling and testing variability associated with voids testing, and (3) contractor unfamiliarity with the new concepts and parameter interactions. The VA projects are expected to perform as well as the OLA projects. Implementation: The long range goal should not change, but VA implementation should be slowed while test methods are refined. During this time, implement Superpave technology. As soon as practical the QLA and VA technologies should be merged into a single specification.