Cold Asphalt Recycling Technologies using Rejuvenating Asphalt Emulsion: Impact, Implementation, Specification
Status: Contract Development
The objectives of this study are:
- Evaluate the efficacy of rejuvenating asphalt emulsions in the CIR and/or CCPR process in terms of potential performance benefits relative to existing stabilization options (e.g., foamed asphalt, engineered emulsion) using concepts of balanced mixture design;
- Provide preliminary usage and design guidelines for the use of rejuvenating asphalt emulsion in CIR and/or CCPR processes;
- Develop a “roadmap” for rapid implementation of a test section utilizing rejuvenating asphalt emulsion stabilization.
The proposed research study will result in a better understanding of the key RA and recycled asphalt properties that influence performance. The unique composition and experience of the proposed research team with RAs and cold recycling processes will aid in successfully completing the proposed objectives.
Task 1: Literature Review and Material Selection
In the first stage RAP, rejuvenator, and bitumen materials will be selected from relevant sources of use within NRRA states. Furthermore, a thorough review of literature will be carried out, the results of which will be a synthesis of prior and ongoing research including but not limited to the NCHRP 09-58 and MnDOT studies on CIR/CCPR. Based on the literature review the test plan will be refined and finalized at the end of this task.
Task 2: Material Collection, Preparation, and Characterization
In this task the material will be collected, prepared (2a), and analyzed using analytical and rheological measures (2b) to determine critical properties of potential importance to final product performance. The following tables provides an overview of the proposed characterization tests to be conducted on the base asphalt, selected RAs, and RAP binder (which will be extracted and recovered from the selected RAP sources):
Task 3: CIR Mix Design and Performance
In the next stage existing CIR mix designs from NRRA states will be leveraged as control materials. Performance testing will then be carried out to identify impact of rejuvenation on the performance and properties of the CIR mix in support of validating or disproving the hypothesis. Design variables will be considered by the research team. The study will utilize the findings of Task 1 to create a smart and efficient partial factorial design based on these parameters.
Note that all asphalt emulsion materials used in this study will be produced in the research team’s laboratory using a controlled source of base asphalt, emulsification, and additive package. The experience of the research team in production of CIR and CCPR emulsions will aid in this endeavor.
Since the overarching objective of this research is to attempt to demonstrate the performance benefits of using a rejuvenating asphalt emulsion for CIR/CCPR, it is anticipated that the mixture performance testing selected will be sourced from both existing CIR design procedure (MnDOT, for example) as well as the Hot Mix Asphalt industry. It is envisioned that two general distresses will be targeted during this study: high temperature deformation resistance (rutting) and cracking. Deformation tests are used principally to place an effective maximum limit of asphalt binder in a mixture while the cracking tests ensure adequate quantity and quality of asphalt binder in the mixture. Final selection will be based upon Task 1 and NRRA feedback.
Task 4 & 5: Draft and Final Deliverables and Communication of Results
- Final Report, documenting findings, conclusions, and detailed results. This will include a proposed method for design and incorporation of rejuvenators in CIR, along with documentation of expected impact. This can include suggested items that may be incorporated into specifications to address such technology.
- Presentation summarizing the research and findings.
- A detailed plan and proposal for construction of innovative rejuvenated CIR test sections at MnROAD or other locations as determined by NRRA members. Although the construction of the test sections is outside the scope of the current proposal, the research team and partners have declared their interest in participating in such a project if it were to be pursued by NRRA.
- Andrew Cascione, Flint Hills Resources
- Mohammad Sabouri, Braun Intertec
- Dan Schellhammer, Midstate Reclamation and Trucking
- Jo E. Sias, University of New Hampshire
- Project Proposal (pdf), 11/24/2019