THE EFFECT OF PYROLYSIS TEMPERATURE ON INTERPHASE INTERACTION AND STRUCTURE FORMATION IN ASPHALT MIXTURES MODIFIED WITH BIOCHAR
DOI:
https://doi.org/10.32782/2415-8151.2026.40.4Keywords:
biochar, asphalt concrete mixtures, pyrolysis temperature, interfa- cial interaction, microporosity, aging, wettability, adhesion, moisture resistance, cracking resistance, bituminous binder, road pavements, structure formation, service durabilityAbstract
Purpose. The purpose of the study is to determine the influence of pyrolysis temperature on interfacial interaction in the «biochar – bitumen – mineral aggregate» system and on the structure formation patterns of asphalt mixtures modified with biochar. Particular attention is focused on identifying the temperature range that provides the best combination of adhesion activity, structural stability, and resistance of the mixture to moisture and thermo-oxidative effects. Methodology. The study is based on a theoretical analysis and synthesis of recent research on pyrolytic biochar production and its use in asphalt mixtures. The influence of pyrolysis temperature was assessed through the properties that directly determine the efficiency of biochar in asphalt mixtures, namely specific surface area, microporosity, content of functional groups, wetting energy, adsorption capacity for light bitumen fractions, and the nature of adhesion to mineral aggregate. The methodological basis of the work is the interpretation of structure formation as a consequence of controlled changes in the interfacial properties of biochar depending on the temperature of its thermal treatment. Results. It was established that pyrolysis temperature is the key parameter governing the functional performance of biochar in asphalt mixtures. At temperatures below 550 °C, volatile and oxygen-containing compounds remain in the biochar structure, which weakens the cohesion of the bitumen film, increases moisture susceptibility, and prevents the formation of a continuous contact layer at the phase boundary. At temperatures above 750 °C, biochar becomes excessively inert, which is accompanied by a decrease in the number of functional groups and poorer wetting by bitumen. The most favorable conditions for interfacial interaction and structural stabilization of the mixture are achieved within the range of 600–700 °C, where biochar acquires an optimal balance of microporosity, moderate polarity, and hydrophobicity. This leads to improved adhesion strength, reduced moisture sensitivity, delayed aging of the bituminous binder, and better structural stability of the asphalt mixture. Scientific novelty. The scientific novelty of the study lies in the systematic substantiation of the relationship between biochar pyrolysis temperature and the mechanisms of its action in asphalt mixtures through changes in surface energy, wettability, adsorption capacity, and the nature of contact with bitumen and mineral aggregate. In contrast to generalized assessments of the prospects for biochar application, the present study focuses on the interfacial mechanisms that determine structure formation and durability. Practical relevance. The obtained results can be used to substantiate the parameters of pyrolytic biochar production intended for asphalt mixture modification, as well as to select technological regimes that ensure improved moisture resistance, aging stability, and structural uniformity of the road material. The practical implementation of this approach creates preconditions for increasing pavement durability and rational use of secondary bioresources in road construction.
References
Krayushkina K. V., Bondarchuk V. S. (2025). Analiz mozhlyvosti vykorystannia biovuhillia v asfaltobetoni [Analysis of the possibility of using biochar in asphalt concrete]. Teoriia ta praktyka dyzainu. Arkhitektura ta budivnytstvo - Theory and Practice of Design. Architecture and Construction, 2(36), 54–64. DOI: 10.32782/2415-8151.2025.36.5. [in Ukrainian].
Barszcz, W., Kaźmierczak, B., Szeląg, M., Swat, M., Wystalska, K., & Kwarciak-Kozłowska, A. (2024). Impact of pyrolysis process conditions on the structure of biochar obtained from apple waste. Scientific Reports, 14, Article 11291. https://doi.org/10.1038/s41598-024-61394-8.
Dassanayake, C., & Mashaan, N. S. (2025). Biochar as additive and modifier in bitumen and asphalt mixtures. Eng, 6, 341. https://doi.org/10.3390/eng6120341.
Jahirul, M. I., Rasul, M. G., Chowdhury, A. A., & Ashwath, N. (2012). Biofuels production through biomass pyrolysis – A technological review. Energies, 5(12), 4952–5001. https://doi.org/10.3390/en5124952.
Kumar, A., Choudhary, R., Narzari, R., Kataki, R., & Shukla, S. K. (2018). Evaluation of bioasphalt binders modified with biochar: A pyrolysis byproduct of Mesua ferrea seed cover waste. Cogent Engineering, 5(1), Article 1548534. https://doi.org/10.1080/23311916.2018.1548534.
Lehmann, J. (2009). Biochar for environmental management: An introduction. In J. Lehmann & S. Joseph (Eds.), Biochar for environmental management: Science, technology and implementation (pp. 1–12). Earthscan.
Li, Q., Xu, L., Chen, X., Li, W., Li, Y., Wang, H., & Liu, K. (2024). Study on the adhesion performance of biochar-modified asphalt based on surface free energy and atomic force microscopy. Coatings, 14(11), Article 1390. https://doi.org/10.3390/coatings14111390.
Lin, Y., Ma, X., Peng, X., Yu, Z., Fang, S., Lin, Y., & Fan, Y. (2016). Combustion, pyrolysis and char CO₂-gasification characteristics of hydrothermal carbonization solid fuel from municipal solid wastes. Fuel, 181, 905–915. https://doi.org/10.1016/j.fuel.2016.05.031.
Loise, V., Calandra, P., Policicchio, A., Madeo, L., Oliviero Rossi, C., Porto, M., Abe, A., Agostino, R. G., & Caputo, P. (2024). The efficiency of bio-char as bitumen modifier. Heliyon, 10(1), Article e23192. https://doi.org/10.1016/j.heliyon.2023.e23192.
Ma, F., Dai, J., Fu, Z., Li, C., Wen, Y., Jia, M., Wang, Y., & Shi, K. (2022). Biochar for asphalt modification: A case of high-temperature properties improvement. Science of the Total Environment, 804, Article 150194. https://doi.org/10.1016/j.scitotenv.2021.150194.
Martinez-Toledo, C., Valdes-Vidal, G., Calabi-Floody, A., Gonzalez, M. E., & Reyes-Ortiz, O. (2024). Evaluation of rheological properties of asphalt binder modified with biochar from oat hulls. Materials, 17(17), Article 4312. https://doi.org/10.3390/ma17174312.
Remisova, E., & Briliak, D. (2023). Evaluation of the effect of thermo-oxidative aging and UV radiation on asphalt stiffness. Materials, 16(10), Article 3716. https://doi.org/10.3390/ma16103716.
Rondón-Quintana, H. A., Reyes-Lizcano, F. A., Chaves-Pabón, S. B., Bastidas-Martínez, J. G., & Zafra-Mejía, C. A. (2022). Use of biochar in asphalts: Review. Sustainability, 14(8), Article 4745. https://doi.org/10.3390/su14084745.
Sharma, A., Pareek, V., & Zhang, D. (2015). Biomass pyrolysis – A review of modelling, process parameters and catalytic studies. Renewable and Sustainable Energy Reviews, 50, 1081–1096. https://doi.org/10.1016/j.rser.2015.04.193.
Sohi, S. P., Krull, E., Lopez-Capel, E., & Bol, R. (2010). A review of biochar and its use and function in soil. Advances in Agronomy, 105, 47–82. https://doi.org/10.1016/S0065-2113(10)05002-9.
Wei, J., Tu, C., Yuan, G., Liu, Y., Bi, D., Xiao, L., et al. (2019). Assessing the effect of pyrolysis temperature on the molecular properties and copper sorption capacity of a halophyte biochar. Environmental Pollution, 251, 56–65. https://doi.org/10.1016/j.envpol.2019.04.069.
Wu, Y., Cao, P., Shi, F., Liu, K., Wang, X., Leng, Z., Tan, Z., & Zhou, C. (2020). Modeling of the complex modulus of asphalt mastic with biochar filler based on the homogenization and random aggregate distribution methods. Advances in Materials Science and Engineering, 2020, Article 2317420. https://doi.org/10.1155/2020/2317420.
Yaro, N. S. A., Sutanto, M. H., Habib, N. Z., Usman, A., Kaura, J. M., Murana, A. A., Birniwa, A. H., & Jagaba, A. H. (2023). A comprehensive review of biochar utilization for low-carbon flexible asphalt pavements. Sustainability, 15(8), Article 6729. https://doi.org/10.3390/su15086729
Zhang, R., Dai, Q., You, Z., Wang, H., & Peng, C. (2018). Rheological performance of bio-char modified asphalt with different particle sizes. Applied Sciences, 8(9), Article 1665. https://doi.org/10.3390/app8091665.
Zhao, S., Huang, B., Shu, X., & Ye, P. (2014). Laboratory investigation of biochar-modified asphalt mixture. Transportation Research Record, 2445(1), 56–63. https://doi.org/10.3141/2445-07.
Zhao, S., Huang, B., Ye, X. P., Shu, X., & Jia, X. (2014). Utilizing bio-char as a bio-modifier for asphalt cement: A sustainable application of bio-fuel byproduct. Fuel, 133, 52–62. https://doi.org/10.1016/j.fuel.2014.05.002
