Term of Award

Summer 2025

Degree Name

Master of Science, Civil Engineering

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Copyright Statement / License for Reuse

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

Department

Department of Civil Engineering and Construction

Committee Chair

Junan Shen

Committee Member 1

Xiaoming Yang

Committee Member 2

Soonkie Nam

Abstract

This study investigates three experimental pretreatment methods for ground tire rubber (GTR) for the modification of properties of the resulting modified asphalt binders. Focusing on workability, durability, and chemical changes throughout the aging process for the binders. These three experimental pretreatment methods were termed the Air Dried, Hand Dried, and Oven Dried methods, referring to their respective treatment processes. All three pretreatments utilize waste engine oil (WEO) as the pretreatment soak; the differing procedure involves heat processing for the mixture. The resulting pretreated GTR-modified binders were compared to the control sample, which contained 10% GTR with no pretreatment. All modified binders for this study used unmodified PG 64-22 for the base. The rotational viscosity (RV) measurements revealed that the pretreatments reduced the viscosity in unaged samples compared to untreated GTR-modified binders, thereby improving workability and pumpability for industrial usage. Dynamic Shear Rheometer (DSR) results indicated that the pretreatment of the GTR influenced both rutting resistance and fatigue cracking; the Hand-Dried samples exhibited the best overall performance after aging. Fourier transform infrared spectroscopy (FTIR) indicated that aging increases the carbonyl index for untreated GTR modified binders but reduces it after aging via the Rolling Thin Film Oven Test (RTFO) and Pressurized Aging Vessel (PAV) for the pretreated GTR modified binders. This reduction suggests that both the addition of GTR and the pretreatment of the ground tire rubber have enabled the binder to resist the formation of carbonyl groups typical of oxidation. Bending Beam Rheometer (BBR) results showed that the Creep Stiffness (S) was lower for pretreated GTR modified asphalt binders versus GTR modified asphalt binders. This reveals that the pretreatments made the binder more flexible in cold climates. Overall, the results demonstrate that GTR pretreatment methods can optimize specific GTR properties within the binder. While also complying with industry standards, enhancing particular properties, and advancing sustainable asphalt production.

OCLC Number

1528852704

Research Data and Supplementary Material

No

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