Evaluation of Aspha-min® Zeolite for Use in Warm Mix Asphalt
The report, authored by Graham C. Hurley and Brian D. Prowell from the National Center for Asphalt Technology, evaluates the effectiveness of Aspha-min® zeolite, a synthetic sodium aluminum silicate, in reducing the mixing and compaction temperatures of hot mix asphalt (HMA) without compromising performance. The study aims to assess the applicability of Aspha-min® under typical U.S. paving conditions, focusing on its impact on compactability, moisture sensitivity, and overall mix performance.
Key findings include:
- The addition of Aspha-min® zeolite improved the compactability of asphalt mixtures, resulting in an average reduction of air voids by 0.65% and allowing effective compaction at temperatures as low as 190°F.
- The zeolite did not significantly affect the resilient modulus or increase the rutting potential of the asphalt mix, although lower mixing and compaction temperatures correlated with increased rutting potential due to reduced binder aging.
- There was no evidence of differing strength gain over time between zeolite-containing mixes and control mixes, suggesting that no cure period is necessary before opening to traffic.
- However, the lower compaction temperatures raised concerns about moisture damage, which was mitigated by the addition of hydrated lime.
- A field demonstration in Orlando, Florida, confirmed that the warm mix produced with Aspha-min® had comparable performance to the control mix, with reduced production temperatures and no signs of moisture damage after one year.
The report concludes that Aspha-min® zeolite is a viable option for producing warm mix asphalt, offering potential benefits in terms of reduced fuel costs and emissions.
This report is significant in the field of asphalt technology as it addresses the growing need for sustainable practices in road construction. By demonstrating that Aspha-min® zeolite can effectively lower production temperatures while maintaining performance, the study contributes to ongoing discussions about environmentally friendly materials and methods in the asphalt industry. The findings are beneficial for engineers, contractors, and policymakers looking to implement warm mix asphalt technologies that reduce energy consumption and emissions, ultimately leading to more sustainable infrastructure development.
