A Performance-Related Approach to the Utilization of Reclaimed Asphalt Shingles (RAS) in Asphalt Mixtures

摘要

Over the past decade processed asphah shingles from manufacturer's waste has been added to the suite of recycled materials used in asphalt mixtures. More recently the use of post-consumer Reclaimed (or Recycled) Asphalt Shingles (RAS) has been introduced to the industry. In 2012, a program was initiated to assess the utilization of RAS in Hot Mix Asphalt (HMA). This program assessed the processes for post-consumer RAS production, RAS consistency, rheological properties, and RAS dosage evaluation. Based on this work, RAS at a relatively modest proportion was accepted by the City of Calgary for use in a standard City mix type. In 2013, a second stage of evaluation focused on assessment of asphalt mixtures incorporating a range of RAS addition. A control mix without RAS was included in the assessment program. The mixture testing program was developed to consider volumetric mix properties, moisture susceptibility, low temperature cracking resistance, fatigue resistance and instability rutting resistance. Generally, the results supported the concept of partial contribution of RAS binder. The indicated acceptable rate of RAS addition was about double what would be considered appropriate when total (or 100 percent) contribution is assumed. This could justify higher rates of RAS addition, without compromising pavement performance.