Microscale interface mechanism of the improved high and low-temperature performance of modified bamboo fibres-reinforced asphalt mixture

ABSTRACT

Using plant fibres to reinforce asphalt mixture and improve its road performance has attracted growing interest. To improve the interfacial adhesion between bamboo fibres (BFs) and asphalt matrix, BFs were treated with acrylate epoxidized soybean oil (AESO) and 4,4'-diphenyl methane diisocyanate (MDI). The high-temperature stability and low-temperature cracking resistance of the modified BFs-reinforced asphalt mixture were evaluated by the rutting and bending experiments, respectively. The dynamic stability at 60°C and the flexural strength at −10°C of the mixture with modified BFs were improved by 21.67% and 22.84%, respectively. Then, molecular dynamic simulations were implemented to investigate the effect of fiber modification on the interface properties. Simulation results showed that as the grafting density increased from 0 to 2.21 × 10^–7 mol/m², the binding energy increased by 277.2% and 159.3% at 65°C and −15°C, respectively, and the diffusion coefficient decreased by 50.8% and 27.7% at 65°C and −15°C, respectively. As the grafting density further increased to 4.43 × 10⁻⁷ mol/m², the interface performance deteriorated because the dense grafted molecular chains inhibited the diffusion of asphalt to BF surfaces. This work provides an understanding of the interfacial mechanism for optimising the BF-reinforced asphalt mixtures.

KEYWORDS:

• Bamboo fibres
• asphalt mixture
• fibre modification
• interface micro-mechanical mechanism
• molecular dynamics simulation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supporting information

Properties of the asphalt. Properties of BFs. Properties of AESO. Information of chemical reagents. FTIR spectra of asphalt, grafting molecule, and mixture of asphalt and grafting molecule. Contact angle of asphalt on BFs at high and low temperatures. Comparison between 70# asphalt and asphalt molecular model.

Additional information

Funding

This work was supported by China Postdoctoral Science Foundation: [grant no 2021M690636]; National Natural Science Foundation of China: [grant no 12002087]; Fujian Provincial Demonstration Project for Communications and Transportation Science and Technology, China: [grant no 2022-1]; the Fujian Provincial Department of Science and Technology, China: [grant nos 2022H6022, 2021J01103]; Fujian Agriculture and Forestry University, China: [grant no Kxjq21018].