Description

A Holistic Solution that Simultaneously Enhances Durability and Promotes Environmental Management: Rubberized-Aerogel

Carlos J. Obando, PhD., Jolina J. Karam, PhD., Jose R. Medina, PhD., Kamil E. Kaloush, PhD.

School of Sustainable Engineering and the Built Environment

Arizona State University

Abstract

Asphalt pavement systems are facing increasing pressure to become more sustainable, resilient, and cost-effective, while also addressing the growing accumulation of industrial waste. Among the most impactful strategies is the incorporation of crumb rubber, a value-added product derived from end-of-life tires, which offers both environmental and performance benefits. With over 280 million tires discarded annually in the U.S., the integration of crumb rubber into infrastructure presents a transformative opportunity to reduce waste and enhance material properties. This study introduces an innovative material solution, RaC (Rubberized-aerogel Composite), which uses crumb rubber as a core component, pre-swelled with recycled lubricating oil to maximize binder compatibility and elasticity. The composite also incorporates aerogels (renowned for their low thermal conductivity) and is encapsulated with asphalt binder, polymers, or latex to form a dry, particulate additive designed for flexible integration into pavement systems. In the context of the U.S.’s massive consumption of 2.47 billion gallons of lubricating oils annually, and the urgent need to reduce greenhouse gas emissions and raw material use, RaC addresses infrastructure challenges with a circular economy approach. Developed at the Advanced Pavement Laboratory at Arizona State University, this patent-pending technology (WO2024173729) improves mechanical performance, thermal resistance, and crack mitigation. Preliminary lab results demonstrate that RaC-modified binders reduce heat absorption, enhance resistance to thermal and fatigue cracking, and extend service life, delivering a more durable and climate-resilient pavement. By making crumb rubber a central actor in this multifunctional material, RaC not only boosts infrastructure performance but also pioneers a scalable pathway for tire waste valorization in modern transportation networks.

Key words: Crumb rubber, Resilient materials, Recycled materials, Aerogel composites