Date of Graduation

5-2024

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering (MSCE)

Degree Level

Graduate

Department

Civil Engineering

Advisor/Mentor

Andrew F. Braham

Committee Member

Suman K. Mitra

Second Committee Member

Jingyi Chen

Third Committee Member

Sundaram Logaraj

Keywords

Asphalt Emulsion; Emulsifiers; FTIR; Soap Solution; TGA

Abstract

Asphalt emulsion finds widespread application in mixtures like Cold Mix Asphalt (CMA) and Warm Mix Asphalt (WMA) due to its capacity to operate at ambient temperatures, thus mitigating environmental impact and fostering sustainability. However, research on the chemical and thermal traits of asphalt emulsion still needs to be completed. Hence, there's a pressing need to develop new formulations of asphalt emulsion to deepen our understanding of its chemical and thermal attributes. This study aims to thoroughly assess chemically and thermally asphaltic materials to uncover insights into their composition and behavior. This investigation scrutinized two asphalt binders, two emulsifiers, two soap solutions, two soap solution residues, four asphalt emulsions, and four emulsion residues. Asphalt binders PG 64-22 and PG 64-10 were sourced from the Middle East and California, respectively, while CMS and CQS emulsifiers were utilized for asphalt emulsion preparation. The recirculating mill method was employed for asphalt emulsion preparation, with FTIR and TGA used to identify functional groups and weight decomposition for each material. The findings revealed that PG 64-22, with higher asphaltene content (12.6%), was classified as the sol-gel type, while PG 64-10 (6% asphaltene) was categorized as the sol type. TGA analysis divided asphalt binder, asphalt emulsion, and emulsion residue into six regions based on the decomposition of various materials such as water, soap solution, soap solution residue, and asphalt binder components. The decomposition was significant, particularly in Region 5, primarily due to resin and asphaltene breakdown. Additionally, adding soap solution increased mass loss by decomposing resin and asphaltene content in the asphalt binder across all four emulsions and residues, resulting in a highly flexible and less dense solution. Despite this, no significant chemical changes were observed. However, the breakdown of asphaltene components into alkane (C-H) groups resulted in a higher (C-H) peak ratio in asphalt emulsion compared to asphalt binder, contributing to lower viscosity. Oxidation of asphalt emulsion residue led to heteroatoms (O) forming, influencing asphaltene association and making the residue stiffer than asphalt emulsion. Therefore, FTIR and TGA analysis are practical tools for characterizing the chemical and thermal behavior of asphalt emulsion.

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