Development of a rapid test to determine moisture sensitivity of HMA (Superpave) mixtures

Abstract

Exiting test methods to determine moisture sensitivity in hot mix asphalt are time consuming and inconsistent. This research focused on wheel tracking devices to develop a rapid test method to evaluate moisture sensitivity. The Asphalt Pavement Analyzer (APA) and the Hamburg Wheel Tracking Device (HWTD) were used for this research. Compacted cylindrical samples were fabricated using the Superpave Gyratory Compactor. Results show that although most mixes without any additive show stripping behavior, APA results do not indicate any stripping inflection points. The HWTD results show stripping inflection points. The APA results show wet tests are severe at lower temperatures whereas dry tests show high rut depth at higher temperatures. The HWTD results show improvement in the performance by the use of anti-stripping agents at later stage. Further studies should be carried out using HWTD to relate number of passes for stripping inflection point with severity of striping. Lab results should be correlated with field performance.