Asphalt fumes released at high temperatures significantly impact human health and the natural environment. This study systematically investigated the microstructure and compositional characteristics of tea stalk biochar (TB) from pyrolysis at different temperatures (300℃, 400℃, 500℃, and 600℃) and its adsorption capacity for asphalt fumes. Scanning electron microscopy and Brunauer-Emmett-Teller analysis indicated that increasing pyrolysis temperatures enhanced the porosity and BET surface area of TB, transitioning its structure from dense and low-porosity to highly porous. Fourier-transform infrared spectroscopy and elemental analysis revealed that higher temperatures promoted biochar graphitization, reduced oxygen-containing functional groups, and increased hydrophobicity and aromaticity. Analysis of asphalt fumes demonstrated that adding 1 % TB significantly reduced asphalt fume emissions, including VOCs, H₂S, SO₂, and NOₓ. TB prepared at 500℃ (500TB) exhibited optimal adsorption, reducing VOCs by 68.6 % and H₂S by 87.5 %. GC-MS analysis further revealed that 1 % 500TB reduced aliphatic hydrocarbons, aromatic compounds, oxygen-containing compounds, and sulfur-containing compounds in asphalt VOCs by 63 %, 69 %, 67.2 %, and 63.3 %, respectively. The superior adsorption performance of 500TB was attributed to its larger surface area, diverse mesoporous structure, and high aromatic carbon content, enhancing its affinity for pollutants. Physical tests indicated that biochar enhances the thermal stability and deformation resistance of asphalt by increasing its softening point, viscosity, and penetration index, while maintaining acceptable ductility. These findings demonstrate the effectiveness of TB for mitigating asphalt fume emissions.

Asphalt fumes released during pavement construction posed a threat to human health and environment. In this study, 9,10-dihydro-9-oxa-10-phosphorophenanthrene-10-oxide (DOPO) was used as a reactive fumes suppressant to reduce the asphalt fumes emission. The volatilization behavior of DOPO modified asphalt (DOPO-Asphalt) was investigated through thermogravimetric analysis, volatility test and thermal destruction gas chromatography mass spectrometry, and effect of DOPO on the chemical structure and composition of asphalt was explored through nuclear magnetic resonance hydrogen spectroscopy, Fourier transform infrared spectroscopy, and asphalt component testing. The results indicated that 1.0 wt% DOPO reduced the fume content of control asphalt by 1.1% from 120 ℃ − 200 ℃ and the H₂S and VOC content by 96.9% and 84.2%, respectively, at 180 ℃. Moreover, 1.0 wt% DOPO reduced the content of aliphatic hydrocarbons, hydrocarbon derivatives, aromatics, and sulfides in control asphalt fumes by 86.8%, 89.7%, 90.7%, and 93.5%, respectively, which may be attributed to electrophilic and nucleophilic reactions between DOPO and volatile substances in asphalt. Chemical structure and composition changing of DOPO-Asphalt confirmed that P-H bond in DOPO was chemically reacted with components in asphalt, generating stable aromatic hydrocarbons and resins. The results provided a novel method for inhibiting the volatilization of harmful substances in asphalt.