Long-term field transverse cracking performance of warm-mix asphalt pavement and its significant material property

With the growing awareness of sustainable construction practices and because warm-mix asphalt (WMA) is environmentally friendly, WMA is gaining popularity for pavement construction in the United States. Currently, it is generally believed that rutting and moisture damage are two major concerns for WMA pavements, but because WMA requires less aging, its cracking resistance is expected to be improved. One of the primary cracking distresses of concern is transverse cracking, which could be thermal cracking in asphalt pavement or reflective cracking in asphalt overlay caused by underlying thermal cracking. Thus, transverse cracking is another primary distress. This study investigated the long-term field transverse cracking of 28 pavement projects, including WMA pavements and corresponding hot-mix asphalt (HMA) control pavements across the United States, covering different climate zones, WMA technologies, service years, pavement structures, and traffic volume levels. Two distress surveys were conducted at an interval of 2 years, and the material properties of the asphalt mixtures and binders were determined with field cores and extracted binders. The longterm field performance of the WMA and HMA pavements were compared for transverse cracking. The study found that HMA and WMA pavements exhibited comparable transverse cracking. Fracture work density obtained from indirect tensile testing at 14°F was found to be the significant determinant for transverse cracking. Significant mix design parameters were identified that can affect the resistance of mixtures to transverse cracking and that can be employed to guide the development of a well-performing mix design.