Thesis
DEVELOPMENT OF MEASURES TO IMPROVE DESIGN AND PERFORMANCE OF ASPHALT MIXES INCLUDING HIGH AMOUNTS OF RAP AND RAS
Washington State University
Master of Science (MS), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004538
Handle:
https://hdl.handle.net/2376/124818
Abstract
Increasing the amount of recycled asphalt pavement (RAP) and recycled asphalt shingles (RAS) in new asphalt pavements can reduce the pavement cost, as the need for virgin binder would be significantly reduced. Generally, the use of RAP and RAS will increase the mix stiffness, reduce the cracking resistance, but improve the rutting susceptibility. In addition, the inclusion of RAP and RAS further complicates the volumetric adjustment of mix design procedure. Several studies have evaluated the effect of RAP and RAS on the volumetric and performance of asphalt mixes. However, a guidance on how to modify the mix design parameters to improve the volumetric properties and performance of mixes designed with high amounts of RAP and RAS is still needed.This thesis evaluated over 300 mix designs that were designed by contractors for paving jobs, or designed in laboratory on different contractors’ materials, to analyze the effect of various mix design parameters on the cracking, rutting, and volumetric properties of asphalt mixes including high amounts of RAP and RAS. It was found that rejuvenators are ineffective to improve the cracking performance of high RAP/RAS mixes, following the current mix design procedure based on WSDOT specifications. Also, the presence of RAP and RAS was found to adversely affect the cracking performance and improve the rutting resistance, regardless of the amount of RAP and RAS in the mix.
In order to effectively develop a mix that contains RAP/RAS, a new method for measuring the surface area of particles inside the mix were proposed, that will allow calculating the film thickness coating the particles. Two regression models were also developed for targeting the voids in mineral aggregate (VMA) and air void content, using the preliminary volumetric variables of the mix, without the need of producing the mix. The models were verified with K Fold cross validation technique and were capable of predicting the VMA with around 90% accuracy, and the mix air void content with above 87% accuracy.
Metrics
2 File views/ downloads
34 Record Views
Details
- Title
- DEVELOPMENT OF MEASURES TO IMPROVE DESIGN AND PERFORMANCE OF ASPHALT MIXES INCLUDING HIGH AMOUNTS OF RAP AND RAS
- Creators
- Maziar Mivehchi
- Contributors
- Haifang Wen (Advisor)Xianming Shi (Committee Member)Saumya Amarasiri (Committee Member)Emad Kassem (Committee Member)Nathan Bower (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Civil and Environmental Engineering
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 122
- Identifiers
- 99900898136501842
- Language
- English
- Resource Type
- Thesis