Graduation Semester and Year

Fall 2024

Language

English

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering

Department

Civil Engineering

First Advisor

Dr. MD Sahadat Hossain

Second Advisor

Dr. Xinbao Yu

Third Advisor

Dr. Laureano Hoyos

Abstract

Reflective cracking in flexible pavements, especially when overlays are applied over existing cracked or jointed pavements, is a significant challenge that compromises roads' longevity and structural integrity. Plastics have emerged as promising modifiers for asphalt to address these issues. The addition of recycled plastics has shown a positive result in enhancing the mechanical properties of pavements, thereby mitigating reflective cracking. Recycling and reusing plastics in asphalt pavement construction presents an innovative and sustainable solution for managing plastic waste. With the world facing mounting challenges due to the excessive accumulation of non-biodegradable plastic waste, integrating these materials into road construction can provide dual benefits: improving the quality of overlays to mitigate reflective cracking, and reducing landfill waste contributing to effective waste management. This study critically reviews the history and methodologies for reusing plastic waste in asphalt. The study involved extensive laboratory testing including volumetric and performance tests to determine the optimum plastic content. The experimental program was conducted using Superpave Type-C mix and PG 64-22 asphalt binder, with plastics replacing 8%, 10%, and 12% of the bitumen by weight. A total of 82 tests were performed, ensuring comprehensive evaluation and repeatability. Results revealed that the asphalt mixes modified with 8% plastic content, particularly combinations of HDPE and LDPE or LDPE and PP, exhibited improved resistance to crack initiation and propagation, outperforming the control sample. However, higher plastic content (10% and 12%) showed a decline in performance, emphasizing the need for an optimal balance. The findings supported using recycled plastic as sustainable additives in asphalt overlays. This provides an environmentally friendly solution that reduces plastic waste while improving pavement performance.

Keywords

Reflective cracking, overlays, recycling, plastic.

Disciplines

Civil Engineering | Geotechnical Engineering | Transportation Engineering

License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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Available for download on Sunday, December 20, 2026

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