Impact of lime application method on ravelling and moisture sensitivity in HMA mixtures

Abstract

This study is sponsored by the Regional Transportation Commission of Washoe County to assess the impact of lime treatment on the moisture damage of hot-mixture asphalt (HMA) mixtures near Reno, Nevada. This paper presents the laboratory evaluation of lime application in HMA mixtures, mechanistic analyses of those results and an evaluation of plant-produced HMA mixtures to evaluate the variability of moisture susceptibility. The laboratory evaluation based upon resilient modulus testing detected moisture sensitivity benefits with the use of lime over multiple freeze–thaw cycles, but could not distinguish between the marinated and non-marinated laboratory mixtures. The mechanistic analysis based upon laboratory mixtures indicated similar results in terms of the presence of lime and showed slight signs of improvement with the marination process. The field variability based on tensile strength ratios (TSR) indicated that the marination process does reduce the variability of the benefits of lime treatment on moisture sensitivity.

Keywords:

• moisture sensitivity
• hydrated lime
• lime application method
• ravelling
• asphalt mixtures
• mechanistic analysis