Laboratory Evaluation of Warm Mix Asphalt Mixtures in South Dakota, USA

Abstract

The implementation of warm-mix asphalt (WMA) is becoming more widespread with a growing number of contractors utilizing various WMA technologies. WMA processes were developed to reduce the mixing and compaction temperatures of hot mix asphalt without sacrificing the quality of the resulting pavement. Early research suggests WMA may be more susceptible to moisture damage and rutting than traditional HMA mixtures.The objective of this research was to evaluate various types of WMA paving technologies relative to HMA mixtures to determine their suitability for use in South Dakota in various applications. This objective was met by conducting an extensive laboratory experiment to assess the performance of WMA mixtures produced using South Dakota's aggregate sources. The conclusions of this study are as follow: * Reduced mixing and compaction temperatures were achieved.* Lower production temperature and short-term conditioning had significant effects on the performance tests' results.* Statistical differences were found when comparing indirect tensile strength (ITS) values for laboratory- produced mixtures. None of the WMA additives performed as well as the HMA. However, WMA mixtures exhibited satisfactory moisture damage resistance when comparing their result to HMA mixtures produced at the WMA temperatures and short-term conditioning.* Flow number and APA results showed that WMA mixtures exhibited accepted level of rutting resistance comparing to HMA mixtures produced at the WMA temperatures and short-term conditioning.* Dynamic modulus results showed that, on average, WMA mixtures had significantly lower dynamic modulus values than HMA mixtures, but similar values to HMA mixtures produced at the WMA temperature and short-term conditioning.