Abstract

Toxic fumes emitted during the construction and maintenance of hot-mix asphalt mixtures represent a significant challenge for both the environment and construction workers. To reduce the generation of these toxic fumes, nano-sepiolite (NSEP, a natural mineral) powder was incorporated into base asphalt (BA), styrene-butadiene-styrene (SBS) -modified asphalt (SBSA), and crumb rubber-modified asphalt (CRA) to formulate sepiolite-modified asphalt binders. The rheological properties of these NSEP-modified asphalts were evaluated using dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests. Subsequently, smoke density tests and gas chromatography-mass spectrometry (GC-MS) were utilized to analyze the quantity and composition of the volatile organic compounds (VOCs) released in the fumes. Finally, Fourier transform infrared spectroscopy (FTIR), fluorescence microscopy (FM), and gel permeation chromatography (GPC) were employed to investigate the physical and chemical changes induced by the addition of NSEP. The results indicate that incorporating 4%, 4%, and 3% of NSEP into BA, SBSA, and CRA, respectively, significantly improves the high-temperature performance of asphalt. At these concentrations, the smoke density rate of BA, SBSA, and CRA decreased by 5.48%, 9.84%, and 7.82%, respectively. The suppression effect on the highly toxic component (2-butenal, 2-methyl-) in SBSA fumes and the highly carcinogenic component (benzo[c]thiophene) in CRA fumes was 61.7% and 80%, respectively. Furthermore, NSEP did not undergo any chemical reactions with asphalt, SBS, or rubber powder. However, it formed three-dimensional spatial networks with these materials and promoted the transformation of small asphalt molecules into large molecules. This is the primary reason for the reduced emission of toxic gases during the thermal decomposition of asphalt and organic modifiers. This research provides a new reference for the development and widespread application of environmentally friendly asphalt.

Department(s)

Civil, Architectural and Environmental Engineering

Publication Status

Full Text Access

Keywords and Phrases

Asphalt smoke; Green construction; Modified asphalt; Sepiolite; Smoke suppression mechanism

International Standard Serial Number (ISSN)

0950-0618

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 Elsevier, All rights reserved.

Publication Date

27 Jun 2026

Download

Full Text Link

Share

 
COinS