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

Abstract

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.