Abstract

The growing use of chemical modifiers and additives in asphalt mixtures necessitates a reliable system for their identification and quantification, crucial for quality control, assurance, and forensic investigations. Fourier Transform Infrared (FTIR) spectroscopy offers a cost-effective method by analyzing the interaction of infrared light with chemical groups, producing distinct spectral fingerprints. This study evaluates 44 materials, including binders, warm mix additives (WMAs), rejuvenators, release agents, and concrete admixtures. It also assesses the ability of FTIR testing to identify and quantify chemical changes and aging in asphalt binders with rejuvenator addition. An Attenuated Total Reflectance (ATR) accessory was employed for practical sample preparation. Using the OMNIC™ library search tool, the FTIR-ATR device demonstrated excellent repeatability in fingerprinting asphalt binders. A subtraction method, with PG 46–34 used as a universal reference, was developed to improve modifier identification accuracy. Most asphalt modifiers were distinguishable via spectral subtraction, except for release agents. Broad peaks above 3000 cm−1, associated with amines, were observed in some WMAs, rejuvenators, and release agents, while narrow peaks around 1750–1700 cm−1 indicated carbonyl groups. Concrete admixtures displayed common peaks at 1750–1500 cm−1 and above 3000 cm−1. Dosage quantifications were attempted by calculating peak ratios, dividing the absorbance at 1430 cm−1 by each modifier's characteristic peak. However, the results were inconsistent in blind samples and varied depending on the type of neat binder used. Differences in FTIR peaks between neat and rejuvenated binders showed that rejuvenated binders exhibited additional peaks and maintained stable characteristic peaks with aging.

Department(s)

Civil, Architectural and Environmental Engineering

Publication Status

Full Text Access

Keywords and Phrases

Additives; Asphalt; Chemical fingerprinting; FTIR Spectroscopy; Modifiers; Quality control

International Standard Serial Number (ISSN)

0950-0618

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Elsevier, All rights reserved.

Publication Date

04 Jul 2025

Share

 
COinS