Quantifying the influence of lipophilic carbon chain length on adhesion between emulsified asphalt and acidic aggregates

ABSTRACT

Emulsified asphalt technology conserves resources and reduces costs while aligning with the principles of low-carbon and high-quality development. Acidic aggregates demonstrate excellent mechanical properties and are suitable alternatives to alkaline aggregates. This study develops molecular dynamics models and macroscopic experiments to quantify the influence of carbon chain length on the adhesion between emulsified asphalt and acidic aggregate interfaces from a molecular perspective. The results revealed that aromatics and saturates exhibit high sensitivity to variations in carbon chain length. Their adsorption on the SiO₂ interface is directly proportional to the carbon chain length. The diffusion coefficient and adhesion parallelly show an initial increase followed by a decrease with the same factors. The van der Waals forces contributed to more than 67% of the adhesion. Water molecules establish hydrogen bonds with the hydroxyl groups on the SiO₂ interface, thereby decreasing the adhesion between the emulsified asphalt and the SiO₂ interface. The strong hydrogen bonds between free water and asphalt hinder the accumulation of asphalt at the SiO₂ interface. In summary, regulating the emulsifier through the carbon chain length and chloride ions enhances the adhesion between the emulsified asphalt and acidic aggregate interface.

HIGHLIGHTS

• The emulsified asphalt adsorbed on the SiO₂ surface increases with the carbon chain length.

• The van der Waals forces contribute more than 67% to the interfacial adhesion between the emulsified asphalt and SiO₂.

• The demulsification rate of emulsified asphalt on the SiO₂ surface decreases as the carbon chain length increases.

KEYWORDS:

• Emulsified asphalt
• adhesion
• interface
• carbon chain length
• hydrogen bonding

Disclosure statement

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

Data availability statement

Data will be made available on request.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (grant number: 52208425), the Natural Science Foundation of Chongqing, China (grant number: cstc2021jcyj-bshX0113), and the National Natural Science Foundation of China (grant number: 52008264).