Atomistic-scale investigation of self-healing mechanism in Nano-silica modified asphalt through molecular dynamics simulation

Abstract

As one of the most widely used nanomaterials in asphalt modification, the nano-silica (nano-SiO2) can significantly improve the self-healing behavior of asphalt eco-friendly. However, understanding of the self-healing mechanism of nano-SiO2 in asphalt is still limited. The objective of the study is to reveal the self-healing mechanism of nano-SiO2 in asphalt by using molecular dynamics (MD) simulations from the nanoscale. A 10 Å (Å) vacuum pad was added between the two same stable asphalt models to represent the micro-cracks inside the asphalt. The self-healing process of virgin asphalt, oxidation aging asphalt, and nano-SiO2 modified asphalt was studied using density evolution, relative concentration, diffusion coefficient, activation energy, and pre-exponential factor. The simulation results conclude that nano-SiO2 improves the self-healing ability of asphalt by increasing the diffusion rate of molecules with aromatic structures without alkyl side chains and molecules with structures with longer alkyl chains. The self-healing capability of asphalt may be principally determined by the diffusion of light components such as saturate, while nano-SiO2 only plays an inducing role. The research findings could provide insights to understand the self-healing mechanism of nano-SiO2 in asphalt for promoting the sustainability of bitumen pavements while increasing their durability. Graphical abstract

Study on Rheological Properties and Modification Mechanism of Budun Rock Asphalt/Nano-Silica Composite Modified Asphalt

“…Henglong, Z et al [30] discovered enhanced compatibility between asphalt and surface-modified nano-SiO 2 through physical properties testing of asphalt and high-temperature storage stability testing under ultraviolet aging conditions. Meanwhile, Long, Z. et al [31,32] unveiled the compatibility principle between nano-SiO 2 and asphalt using molecular dynamics (MD). The compatibility of nano-SiO 2 with saturates surpasses that with asphaltenes.…”

Experimental Study on Durability Degradation of Geopolymer-Stabilized Soil under Sulfate Erosion

“…However, the environmental pollution caused by cement utilization has not been completely solved. So far, the research work is mainly concentrated on understanding the inherent mechanisms of polymers through molecular dynamics simulations and micro-characterization technology [ 28 , 29 , 30 ]. There is still a lack of systematic research on the durability and microscopic mechanism of alkali-excited all-solid waste-based stabilized soils under sulfate erosion.…”