Session: Research Posters

Paper Number: 173427

Influence of Micro-Scale Recycled Plastic Texture and Size on the Rheological Performance of Ldpe-Modified Asphalt Binders 

With increasing pressure to reduce plastic waste and improve pavement sustainability, the use of recycled plastic, particularly low-density polyethylene (LDPE), as a modifier for asphalt binder has gained considerable interest. While several studies have demonstrated the benefits of plastic-modified binders, limited attention has been given to how the physical characteristics of the plastic, such as particle size and surface texture at the micro-scale, influence binder performance. This study aims to investigate how variations in LDPE texture and particle size affect the rheological and mechanical performance of asphalt binders, with the goal of optimizing recycled plastic usage in road construction.

Recycled LDPE samples were processed using three different preparation methods to produce varied surface textures: shredded, cut, and palletized. Each texture type was further classified into three size ranges: 2.36-4.75 mm, 1.18-2.36 mm, and below 1.18 mm. All LDPE textures and sizes were incorporated into a PG 67-22 asphalt binder at a uniform dosage of 2% by weight. The chemical composition and thermal transitions of the plastics were first analyzed using Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC), respectively, to establish baseline material properties.

Rheological and performance testing of the modified binders included rotational viscosity, Dynamic Shear Rheometer (DSR) testing to evaluate complex modulus and phase angle, Multiple Stress Creep Recovery (MSCR) for rutting resistance, Linear Amplitude Sweep (LAS) for fatigue life prediction and the Binder Yield Energy Test (BYET) to assess energy dissipation under strain.

Results showed that all LDPE-modified binders exhibited higher viscosity than the base PG 67-22 binder, with values that were comparable to or slightly lower than those of a PG 76-22 binder. Additionally, the modified binders demonstrated improved rutting performance, characterized by higher failure temperatures, increased elastic recovery (R%), and lower non-recoverable creep compliance (Jnr) than the base binder. Despite these overall improvements, no clear or consistent trend emerged when comparing binders across different plastic sizes or textures. Specifically, the effect of texture varied depending on the size range considered, and vice versa, the effect of size differed depending on the texture. This suggests that binder performance is influenced by a complex interaction of factors beyond particle size alone, including surface morphology and the binder-plastic compatibility.

Overall, the study highlights the potential of recycled LDPE as a functional asphalt binder modifier, while also emphasizing the importance of understanding microstructural variables in material design. These findings support the advancement of sustainable, circular solutions in pavement engineering and offer practical guidance for optimizing polymer modification strategies using recycled plastics.

Presenting Author: Abeeb Oyelere University of South Alabama

Presenting Author Biography: Abeeb Oyelere is a PhD candidate at the University of South Alabama. With a solid background in both materials and transportation engineering, he is committed to developing resilient, sustainable, and innovative construction solutions in the pavement industry through research that emphasizes life cycle assessments and environmental impacts. Abeeb is also an advocate for environmental equity, striving to ensure that sustainable initiatives benefit all communities while promoting social and ecological responsibility.

Authors:

Abeeb Oyelere University of South Alabama
Tyler Saxon Auburn University
Micah Lee Florida Agricultural & Mechanical University
Shenghua Wu University of South Alabama