Nanoclay application to asphalt concrete: Characterization of polymer and linear nanocomposite-modified asphalt binder and mixture

• Virgin binder was modified with a linear-SBS polymer and OMMT.
• Nanoclay enhances physical and rheological properties of a SBS-modified binder as well as its storage stability.
• Nanocomposite modified asphalt improves performances of asphalt mixture at medium to high temperatures.
• Polymer and nanocomposite modified-asphalt mixtures are more resistant to moisture damage than conventional asphalt mixture.
• Nanocomposite asphalt mixture has less rut depth and is less susceptible to temperature changes than unmodified mixture.

This paper presents and discusses benefits of nano engineering in asphalt binder and asphalt mixture; mainly the performances of polymer, nanoclay and nanocomposite-engineered asphalt mixtures were evaluated. A 58-10 performance grade conventional asphalt (CA), a base binder, was modified separately with a linear SBS polymer and nanoclay at different proportions. As a result, three modified binders: nano modified asphalt (NMA), polymer modified asphalt (PMA), and nanocomposite modified asphalt (NCMA) were made. These modified binders were used to prepare asphalt mixtures. A laboratory study included characterization of physical, mechanical, and rheological properties and behaviors of the modified binders and the asphalt mixtures were performed. Asphalt binder tests were used for the modified binders while performance tests such as tensile strength, resilient modulus and rutting tests were employed for the asphalt mixtures. Test results have shown that nanoclay can enhance physical and rheological properties of the PMA binder as well as its storage stability. With these enhanced binder characteristics, the asphalt concrete specimens showed an increase of tensile strength and resilient modulus and also improved rutting resistance over conventional asphalt concrete.