Using Silane Coupling Agent Coating on Acidic Aggregate Surfaces to Enhance the Adhesion between Asphalt and...

Granite aggregates are known for their durability and resistance to wear. However, their weak bonding with asphalt limits their use in road construction. Basalt and limestone are more commonly used due to better adhesion. Prior research has shown that chemical treatments can alter surface properties. No prior work had resolved the issue of poor adhesion with acidic aggregates. This gap motivated the investigation into silane coupling agents. Researchers propose these agents might improve bonding by modifying surface chemistry. Molecular dynamics simulations offer a way to study such interactions. This paper contributes by testing both experimental and computational approaches.

The aim of this study was to evaluate if silane coupling agents could improve adhesion between asphalt and acidic aggregates. Granite was selected as the primary material due to its poor bonding with asphalt. The researchers sought to compare modified and unmodified aggregates. They used boiling, immersion, and freeze-thaw tests to assess adhesion. Molecular dynamics simulations were added to understand the mechanism. This approach allowed for both macro and micro-level analysis. The goal was to determine if silane treatment could match the performance of alkaline aggregates. The study aimed to provide a scientific basis for using acidic aggregates in pavement construction.

The researchers treated granite surfaces with the silane coupling agent KH-560. They prepared asphalt mixtures with both modified and unmodified aggregates. Basalt and limestone were also tested for comparison. Three adhesion tests were conducted: boiling, immersion, and freeze-thaw splitting. These tests measured the strength of the asphalt-aggregate bond. A molecular dynamics simulation was performed to examine the interface at the atomic level. The radius distribution function and interaction energy were the main metrics. These tools helped quantify the spatial and energetic interactions between molecules.

The silane treatment significantly improved adhesion between asphalt and granite. The modified granite performed similarly to alkaline aggregates in adhesion tests. The boiling and immersion tests showed reduced stripping of asphalt from treated surfaces. The freeze-thaw test confirmed the durability of the modified bond. Molecular simulations revealed higher asphalt molecule concentration on treated surfaces. The radius distribution function showed closer molecular packing near the interface. Interaction energy increased due to stronger non-bonded forces. These findings suggest the silane agent enhances both physical and chemical bonding.

The study demonstrated that silane coupling agents can improve adhesion between asphalt and acidic aggregates. The treated granite matched the performance of alkaline aggregates in adhesion tests. Molecular simulations supported the experimental results by showing increased interaction energy. The researchers propose that silane treatment alters surface chemistry to favor asphalt bonding. This approach may expand the use of acidic aggregates in pavement construction. The findings suggest a practical method for enhancing road material performance. The study does not claim to address all adhesion challenges in pavement engineering. It provides a basis for further investigation into chemical treatments for construction materials.