Graduation Semester and Year
Fall 2025
Language
English
Document Type
Thesis
Degree Name
Master of Science in Civil Engineering
Department
Civil Engineering
First Advisor
Dr. MD Sahadat Hossain
Abstract
EVALUATE THE FEASIBILITY OF THE RECYCLABILITY OF PLASTIC MODIFIED RAP IN HOT MIX ASPHALT
Aashish Acharya
The University of Texas at Arlington, 2025
Supervising Professor: Dr. MD Sahadat Hossain
Recyclability is the primary concern regarding the implementation of plastic-modified asphalt. Conventional Reclaimed Asphalt Pavement (RAP) is commonly reused; however, there are limited studies on RAP from plastic-modified mixes because field-aged material is not yet available. The use of recycled plastics in asphalt is mainly at the research stage and not widely used in practice. This creates a practical concern: if Plastic-RAP cannot be recycled, or if adding Plastic-RAP lowers the quality of new mixes compared with conventional RAP, plastic roads could create a new waste stream. This thesis examines whether RAP sourced from high-density polyethylene (HDPE)-modified mixes can be reintegrated into new hot-mix asphalt without compromising quality.
A laboratory protocol was developed to produce a representative Plastic-RAP. HDPE-modified loose and compacted mixtures for a surface course were prepared, conditioned to reflect short- and long-term aging, and mechanically crushed to create Plastic-RAP in the laboratory. Two plastic modified mixes were prepared with Plastic-RAP, using binder grades PG 64-22 and PG 70-22; each was compared with conventional mix without plastic and with a conventional RAP mix from Dallas. The evaluation covered volumetrics and compatibility (Gmm, Gmb, air voids), moisture susceptibility (TSR), tensile resistance (IDT), rutting performance (Hamburg wheel tracking), and fatigue behavior (Overlay test).
Results show that Plastic-RAP mixtures with 8% HDPE, as well as the mix without additional plastic, compacted within the Superpave target air-void range of 3-5% met volumetric requirements. When Plastic-RAP replaced conventional RAP at the same recycling level, the mixtures maintained or improved rutting and moisture performance while meeting design criteria. Although mixtures with Plastic-RAP showed a slight reduction in indirect tensile strength, overlay testing indicated better crack tolerance and greater resistance to reflective cracking. Overall, hot-mix asphalt produced with Plastic-RAP is practically recyclable, and this work provides a lab-scalable protocol and supporting evidence for closed-loop reuse within standard mix design.
Keywords
Recyclability, Plastic-RAP, Aging, Rutting, Cracking
Disciplines
Civil and Environmental Engineering | Geotechnical Engineering
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Acharya, Aashish, "EVALUATE THE FEASIBILITY OF RECYCLABILITY OF THE PLASTIC MODIFIED RAP IN HOT MIX ASPHALT" (2025). Civil Engineering Theses. 467.
https://mavmatrix.uta.edu/civilengineering_theses/467