In Maine, engineers turn about 1 million scrap tires a year into lightweight highway fill; the shredded rubber stabilizes embankments built on weak marine clay

In Maine, shredded tyres have been repurposed as construction material. Tyres that have been shredded to produce tyre-derived aggregate (TDA), also referred to as tyre chips, have been used as a fill material in highway embankments in areas with weak foundations, according to U.S. Federal Highway Administration guidance on civil engineering applications of scrap tyres. The largest use of tyres was in the construction of the Portland Jetport Interchange. Approximately 1.2 million passenger‑tyre equivalents from an abandoned stockpile were converted into tyre‑derived aggregate used as lightweight fill in highway approach embankments. The tyre aggregate was used in weak marine clay to reduce the load from the embankment on the foundation. This project shows how used tyres can be applied in civil engineering. Used tyres have a low unit weight, making it possible to build embankments without the loads created by conventional soil fills. The Maine Turnpike Authority saved approximately $250,000.

Shredded tyres reduce the load imposed on weak foundations