Road recycling in Phoenix

摘要

That changed when the team at Solterra Materials, a Phoenix-based asphalt mix company, suggested building a trial section of road using RAP to demonstrate the benefits of this material. Based on initial lab results that looked at RAP with Cargill's plant-based rejuvenator, the firm carried out the pilot programme. Asphalt in Arizona is stiff and brittle to cope with high temperatures. To mitigate this, Solterra examined a number of rejuvenator types; fatty acids, vegetable oils, petroleum-based and vegetable oil blends so as to see which would yield the best results. It was determined that Cargill's Anova vegetable oil- base rejuvenator, with a slight asphalt grade bump, was the most effective. Following extensive lab evaluation of RAP properties at 10%, 15% and 25%, a 1.6km test section of the busy Buckeye Road, just west of central Phoenix, was selected for the pilot programme. Solterra worked closely with the Cargill team to establish the optimum Anova dosage. Around 2,075tonnes of hot mix was produced for the surface course containing 20% RAP. The mix with Cargill's Anova rejuvenator performed the best compared to all the other mixes and also was less expensive, according to Solterra Materials. The firm said that modern bio-based chemistries help restore the RAP binder's rheological properties while adding other benefits such as reduced compaction temperatures of 7°C, lower volatile organic compounds (VOCs), low volatile mass loss and better resistance to low temperature cracking.