Dissertation
EVALUATION OF LONG-TERM PERFORMANCE OF HIGH RECYCLED ASPHALT PAVEMENT (RAP) MIXES AND DEVELOPMENT OF MODELS FOR RAP BINDER CONTRIBUTION AND AGING
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004366
Handle:
https://hdl.handle.net/2376/123991
Abstract
Recycled asphalt pavement (RAP) is one of the most recycled materials in the United States. It provides many environmental and economic benefits, but RAP usage has stagnated recently. The advancement in rejuvenators and performance testing renews the ability to increase RAP levels and address cracking concerns. This study investigated the use of RAP in asphalt concrete and if it could be increased beyond current limits without adversely affecting long-term performance. These results provide evidence and tools for increasing RAP both in the mix design and production stages. Additionally, the models developed can make implementing performance testing in production much more feasible. Field constructability and performance were first evaluated to ensure current high RAP (HR) mixes are performing adequately. This systematic approach found that HR mixes performed equal or better than low RAP (LR) typical mixes with lower density deviation and less longitudinal cracking. Then, super high RAP (SHR) mixes, with RAP levels up to 100%, were designed using current WSDOT volumetric design standards. SHR mixes were statistically similar in rutting and cracking performance to typical 20% RAP mixes except for polymer modified binder mixes with RAP levels above 80% due to an overall reduction in polymer and degradation of polymer cross-linking. Cracking performance could be improved with the slight addition of a virgin binder.
With SHR mixes showing potential, models based on mix mechanics were developed to aid in implementation. First, a model to predict RAP binder contribution (PRBC) was developed based on mix performance testing. Lab results showed that the mix with a neat virgin binder with softer RAP contributed more than the modified virgin binder with stiffer RAP. The model was then adjusted for use with plant mixes and showed HR mixes, and V binders with more PRBC than LR mixes and H binders. An aging model was then developed to predict cracking performance as a mix aged. Next, a logarithmic-based model was chosen to predict aged CTIndex results, which characterizes both oxidative aging and polymer degradation. Finally, a 3D model was created to predict the effects of both RAP addition and aging on CTIndex samples.
Metrics
Details
- Title
- EVALUATION OF LONG-TERM PERFORMANCE OF HIGH RECYCLED ASPHALT PAVEMENT (RAP) MIXES AND DEVELOPMENT OF MODELS FOR RAP BINDER CONTRIBUTION AND AGING
- Creators
- Logan Cantrell
- Contributors
- Haifang Wen (Advisor)Saumya Amarasiri (Committee Member)Xianming Shi (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Civil and Environmental Engineering, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 169
- Identifiers
- OCLC#: 1365273233; 99900883038901842
- Language
- English
- Resource Type
- Dissertation