Performance of Modified WMA Mixtures Prepared Using the Same Class PG Binders of HMA Mixtures

摘要

When the same class performance graded (PG) binders are used, the asphalt mixtures using the same aggregate and gradation are expected to perform similarly whether they are the hot-mix asphalt (HMA) or warm-mix asphalt (WMA). In this study, HMA and WMA mixtures with the same class PG binders were used to compare their performance. Two high-temperature (60℃) rut-related properties were evaluated, the wheel tracking (WT) and the strength against deformation (S_D). One ambient-temperature (25℃) property, the indirect tensile strength (S_t), was also evaluated. The performance grades of normal (unmodified) and modified binders for all WMA and HMA mixtures were 64-22 and 76-22, respectively. According to study results, the modified WMA mixtures, which were short-term aged at 135℃, did not show high enough S_D and WT resistance at 60℃ than the HMA mixtures prepared using the same class PG binders, 76-22. However, the same WMA mixtures were found to be similar to or better than HMA mixtures in S_t. Therefore, it was found that tensile strength of WMA mixtures was not inferior to HMA at ambient temperature. However, rut-related properties of modified WMA mixtures were observed to be inferior to the same PG HMA mixtures at high service temperature.