Roads are made of asphalt. Asphalt is a combination of sand, a stone and gravel aggregate; and bitumen. Bitumen is a liquid or semi-solid form of petroleum. Petroleum is also the key ingredient in plastic.
Plastic Roads are made by replacing some of the new bitumen (new petroleum) in asphalt with recycled plastic (recycled petroleum). In the resulting mixture, there is guaranteed to be no more leaching than there is from conventional roads. Indeed, the scientific studies indicate there is far less leaching.
For more information about leaching, you may want to review the following studies. Relevant conclusions are copied below.
| McCartney, T. “Do microplastics from the road get washed off into the environment?” MacRebur, the Plastic Road Company 12 September 2019 from https://www.macrebur.com/pdfs/product/MacRebur_MicroPlastics_Leaflet_v3.pdf
Using waste plastics as plasticisers in roads enhances the asphalt mix making it more durable as a road surface. As long as the asphalt is heated to the correct temperatures and the asphalt manufacturer and the plastic road company adhere to the highest quality control standards, there are no microplastics present in a ‘plastic road’, only a resultant enhanced asphalt.
| Vasudevan, R.”Use of Plastics Waste in the Construction of Tar Road — Excerpts from the paper submitted for Seminar on Integrated Development of Rural and Arterial Road Network for Socioeconomic Growth”, Echo-Ecos Vol 5 Issue 2 April – June 2004 from http://icpe.in/Eco%20Echoes/2004/Apr_June_2004.pdf
Leaching Test: Polymers are not soluble in water or acids and even in most of the organic solvents. The toxicity test solution is 5% acetic acid. The polymer waste is tested with this 5% acetic acid solution (EPT) and it is observed that there is no dissolution of polymer. Therefore it may be concluded that polymer will not leach out of the bitumen layer, even after laying the road using waste plastics-bitumen-aggregate mix.
| White, G. (27 Feb 2019) “EVALUATING RECYCLED WASTE PLASTIC MODIFICATION AND EXTENSION OF BITUMINOUS BINDER FOR ASPHALT” Eighteenth Annual International Conference on Pavement Engineering, Asphalt Technology and Infrastructure, At Liverpool, England, United Kingdom, 27-28 February. 09 Sept 2019 from https://www.researchgate.net/publication/331465864_
and_Extension_of_Bitumous_Binder_for_Asphalt“Three commercially available recycled plastic products for binder extension and modification were evaluated in the same stone mastic asphalt mixture in the laboratory. … No adverse effect was detected with regard to toxic fume generation or hazardous leachate.“