01684194

Component

http://www.trb.org/Main/Blurbs/178080.aspx

This study focused on developing laboratory aging protocols to simulate asphalt aging and aggregate asphalt absorption of asphalt mixtures as produced in a plant and throughout the initial period of pavement performance (i.e., approximately 1 to 2 years after construction). The research efforts also identified the effects of the following factors on the aging characteristics of asphalt mixtures: warm mix asphalt (WMA) technology, aggregate asphalt absorption, plant temperature, plant type, presence of recycled materials, and asphalt source. In this project, the effects of both short-term and long-term aging on asphalt mixtures were primarily evaluated using the resilient modulus test per ASTM D7369 at 77°F (25°C) and the Hamburg Wheel-Tracking Test (HWTT) per AASHTO T 324 at 122°F (50°C). A limited amount of dynamic modulus (E*) testing was conducted in accordance with AASHTO TP 79-13. This project was successful in validating the proposed short-term oven aging (STOA) protocols of 2 h at 275°F (135°C) and 240°F (116°C) for preparing hot mix asphalt (HMA) and WMA mixtures, respectively, in the laboratory that were comparable to those produced at the asphalt plant. Desirable correlations between laboratory mixed, laboratory compacted (LMLC) specimens versus plant mixed, plant compacted (PMPC) specimens and field cores at construction in terms of mixture volumetric, stiffness, and rutting resistance were achieved by asphalt mixtures with a wide range of mixture components and production parameters. In addition, the cumulative degree days (CDD) concept was proposed as a novel metric to quantify field aging of asphalt mixtures, which was able to account for the differences in construction dates and climates for various field sites. Research efforts were also devoted to identify the correlation of field aging with laboratory long-term oven aging (LTOA) protocols based on mixture property ratio results. The two protocols of 2 weeks at 140°F (60°C) and 5 days at 185°F (85°C) were representative of field aging at approximately 9,600 and 17,500 CDD values, respectively. Field aging at 9,600 CDD values was equivalent to approximately 7 months in-service in warmer climates and 12 months in-service in colder climates. As for the field aging at 17,500 CDD values, approximately 12 and 23 months in-service were required for warmer climates and colder climates, respectively. Finally, the effects of various factors in terms of mixture components and production parameters on the aging characteristics of asphalt mixtures were identified. WMA technology, recycled materials, aggregate asphalt absorption, and binder source showed a significant effect; while the effect from production temperature and plant type was insignificant.

01684114

English

pp 21-33

2018-8

Transportation Research Circular

Digital/other

Figures; References; Tables

Aging (Materials); Asphalt mixtures; Laboratory tests; Mix design

Highways; Materials; Pavements

TRIS, TRB, ATRI

Oct 22 2018 3:43PM

• Characterization of Pavement Performance Based on Field Validation Test Site Data Interpreted by an Asphalt Composition Model of Binder Oxidation
• Evaluation of Two Comparative Test Projects in Minnesota and the Relationship Between Binder Composition, Binder Aging, and In-Service Mixture Performance
• How Mixture, Fabrication, and Plant Production Parameters Affect Mixture Properties