Design, Construction, and Early Performance of Virginia’s Hot-Mix Asphalt Stabilizer and Modifier Test Sections

Abstract

Three modifiers and two types of fibers (stabilizers) for hot-mix asphalt commonly available in Virginia were evaluated. Ten test sections were built on I-66, west of Manassas, Virginia. The modified asphalts complied with the specifications for performance grade 76-22 and were placed in dense-graded Marshall and coarse-graded Superpave mixes. The fibers were placed only in the dense-graded Marshall mixes. During design the dense-graded Marshall mix complied with all of the Superpave requirements except for the gradation, which passed through the restricted zone. Samples from the sections were tested for asphalt content, gradation, and Superpave and Marshall volumetrics and were rut studied using both the Georgia loaded-wheel tester and the asphalt pavement analyzer. Field samples generally passed Marshall volumetrics and generally failed Superpave volumetrics. Neither laboratory compaction method correlated with the ultimate field densities. Both tests indicated that the sections were rut resistant. All of the sections have been rut resistant and have performed well in the field after 45 months of service.