Qualitative and quantitative analysis of bio-oil/biochar in asphalt using a novel method based on infrared spectroscopy and microstructure

Zhou, Xinxing, Zhang, Ziyang, Yang, Chunping, Wang, Haopeng ORCID: 0000-0002-5008-7322 and Li, Linglin (2025) Qualitative and quantitative analysis of bio-oil/biochar in asphalt using a novel method based on infrared spectroscopy and microstructure Construction and Building Materials, 501. p. 144280. ISSN 0950-0618, 1879-0526

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Abstract

Detecting and quantifying bio-oil and biochar in asphalt pose significant analytical challenges due to their chemical complexity. This work aims to develop a novel method based on Fourier transform infrared spectroscopy micro-spectroscopy (FT-IRM), fluorescence microscope (FM) and atomic force microscopy (AFM) to qualitatively and quantitatively analyze the bio-oil and biochar in asphalt. The carbonyl index and carboxylic acid index of 2 % BBMA are 0.148 and 0.019, respectively. This study demonstrates that attenuated total reflection (ATR)-FTIR is a superior technique for characterizing the functional groups of bio-oil/biochar-modified asphalt (BBMA), while microscopic techniques such as AFM and FM are more suitable for analyzing its micro-morphology. For biochar characterization, reflection-mode FTIR was found to be the most effective configuration. FT-IRM results indicate that the optimal incorporation amounts of bio-oil and biochar are 15 % and 2 %, respectively. The addition of bio-oil increases the content of C C double bonds, C O double bonds, and N-H groups in the asphalt, while reducing the content of -CH3 groups. Biochar promotes the condensation and dehydrogenation of aromatic rings in bio-oil-modified asphalt, thereby enhancing its degree of unsaturation. While bio-oil is relatively sensitive to ultraviolet (UV) aging, biochar exhibits high resistance to UV degradation and can effectively mitigate the UV aging of asphalt. This study presents a novel multi-modal methodology that provides a promising framework for the qualitative and quantitative analysis of bio-oil and biochar in asphalt.

Item Type:	Article
Uncontrolled Keywords:	Asphalt, Bio-oil, Biochar, Quantitative analysis, Fourier transform infrared spectroscopy micro, spectroscopy
Divisions:	Faculty of Science & Engineering Faculty of Science & Engineering > School of Engineering Faculty of Science & Engineering > School of Engineering > Civil and Environmental Engineering
Depositing User:	Symplectic Admin
Date Deposited:	14 Nov 2025 09:06
Last Modified:	10 Apr 2026 19:55
DOI:	10.1016/j.conbuildmat.2025.144280
Related Websites:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3195389
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