Laboratory evaluation of foamed asphalt mixtures with 100% RAP and rejuvenator

ABSTRACT

This study, conducted in Georgia, analyzes the impact of rejuvenators on foamed asphalt mixtures containing 100% reclaimed asphalt pavement (RAP) and assesses the feasibility of using the mixture as a structural layer in a pavement system. Three laboratory tests, the Marshall stability (MS), indirect tensile strength (ITS), and semi-circular bending (SCB), were conducted for the structural evaluation. Results indicate that the MS and ITS of the mixtures without rejuvenator are sufficiently high for use as a subsurface structural layer. However, dosing the mixture with ≥6% rejuvenator significantly decreases the MS and ITS. SCB tests for fracture resistance at an intermediate temperature indicate that mixtures without rejuvenators are more brittle than conventional hot mix asphalt (HMA). The flexibility index indicates that the mixtures with ≥6% rejuvenator have higher crack resistance than HMA and no-rejuvenator 100% RAP foamed asphalt mixtures. In conclusion, addition of rejuvenators significantly affects the structural integrity of 100% RAP foamed asphalt mixtures by increasing the cracking resistance but considerably decreasing the stability and indirect strength. Therefore, for practical purposes, the use of a rejuvenator in foamed asphalt mixtures is not recommended.

KEYWORDS:

• Rejuvenator
• reclaimed asphalt pavement
• foamed asphalt
• cold recycling
• Marshall stability
• indirect tensile strength

Acknowledgments

The authors are grateful for the financial support of the Georgia Department of Transportation to conduct this research. The authors would also like to thank the asphalt plants and suppliers of other materials for their generosity.

Availability of data

The data that support the findings of this study are available from the corresponding author, M. Jeong, upon reasonable request.

Disclosure statement

In accordance with Taylor & Francis policy and my ethical obligation as a researcher, I am reporting that I have no financial and/or business interests. The primary author, M. Myung Jeong received a research grant from the Georgia Department of Transportation under Grant No. 16-32.

Human/animal rights

This article does not contain any studies with human or animal subjects performed by any of the authors.

Additional information

Funding

This work was supported by the Georgia Department of Transportation under Grant (Research Project) No. 16-32.

Notes on contributors

M. Myung Jeong

M. Myung Jeong, PhD, is an Associate Professor in the Department of Civil Engineering and Construction at Georgia Southern University. His primary research interests include asphalt material characterization and pavement quality assurance. He has been participating on several research projects with Georgia DOT and Arizona DOT related to Warm Mix Asphalt, Cold Mix Asphalt, 100% Reclaimed Asphalt Pavement, and Asphalt Rutting Characterization using the Hamburg Wheel Tracking device.

Sungun Kim

Sungun Kim, PhD, is a senior researcher and lecturer in the department of regional infrastructures Engineering at Kangwon National University in South Korea. He has been involved in numerous asphalt-related research projects in South Korea and the United States. His expertise lies in performance assessment for construction materials using various laboratory evaluation techniques.

Junan Shen

Junan Shen, PhD, is a professor and the director of the Asphalt Research Laboratory in the department of Civil Engineering and Construction at Georgia Southern University. He is also an Associate Editor for the American Society of Civil Engineers (ASCE) Journal of Materials in Civil Engineering, and is a standing member of the ASCE Technical Committee on Asphalt Rubber. He  has completed over $1 million in externally funded research, and has published more than 100 scholarly works related to Transportation Engineering, focusing primarily on Asphalt Paving Materials and Geotechnical Engineering.