Scrap tire generation continues to outpace end-market development. According to the Washington-based U.S. Tire Manufacturers Association’s (USTMA’s) “2021 Scrap Tire Management Report,” which was published Oct. 25, end markets consumed 71 percent of annually generated scrap tires in 2021, compared with 76 percent in 2019 when the USTMA released a similar report.
Over the past decade, the consumption of scrap tires has not kept pace as scrap tire generation has increased. In 2013, about 96 percent of scrap tires generated were consumed by end markets, but in 2015, that figure decreased to 88 percent, and in 2017, that figure was down to 81 percent.
USTMA says this latest slump is due to a 13 percent increase in scrap tire generation, while markets that consume scrap tires only increased by 6 percent.
“Generation is increasing faster than the markets that are able to accept that, and what we need is more recycling markets that can accept scrap tires that are being generated,” says John Sheerin, director of end-of-life tire programs at USTMA.
Sheerin adds that he does not think the generation of scrap tires will slow down in the near term, increasing the need for more end markets for scrap tires.
“Over time, we’re going to see more scrap tires being generated as the automotive market electrifies and as we continue to get more and more vehicles on the road and drive them further every year, so we expect that the generation trend will continue,” he says.
However, USTMA reports that it sees opportunities for scrap tire end-use markets to grow.
“On the recycling side, we saw some real nice increases in the ground rubber market [in 2021],” Sheerin says. “We expect those will continue from what I’m hearing in the marketplace. The rubber-modified asphalt market is growing very solidly, and it will continue to in 2023, hopefully into 2024. The mulch market had a huge increase in 2021. So, these ground rubber markets should tend to increase, and we need them to increase at a greater pace so we can bring our actual beneficial use rate back up toward our objective, which is 100 percent of scrap tires going into sustainable and circular U.S. markets.”
USTMA says it also sees the following opportunities in the near term, including:
Infrastructure opportunities: With the passage of the Bipartisan Infrastructure Law, USTMA wants to grow scrap tire markets that offer sustainable infrastructure solutions. USTMA says it has worked with congressional leaders to identify provisions in the Bipartisan Infrastructure Law that support scrap tire recycling and the use of scrap tires in rubber-modified asphalt and tire-derived aggregate in civil engineering projects. USTMA says it also identified six specific policy proposals, ranging from tax incentives to research dollars and procurement commitments, that support the implementation of scrap tire infrastructure technologies.
Scrap tire management programs: USTMA says it’s important for states to offer robust scrap tire management programs that generate revenue streams to fund research that develops and assesses existing and emerging markets and addresses scrap tire abatement.
Scrap tire partnerships: USTMA has been working with stakeholders to encourage the growth of circular, sustainable scrap tire markets. In 2021, USTMA collaborated with The Ray, a philanthropic organization dedicated to the discovery and implementation of sustainable transportation technologies, and researchers at the University of Missouri-Columbia to produce a State of Knowledge report on rubber-modified asphalt. USTMA says it plans to release similar research about tire-derived aggregate in partnership with the Tire and Rubber Association of Canada, Liberty Tire Recycling, First State Tire Recycling, and the University of Wisconsin. USTMA says it also is planning a scrap tire conference in 2024 to expand collaborative networks and partnerships.
End-use market outlook
For many years, tire-derived fuel (TDF) served as the largest end market for scrap tires. According to USTMA’s 2021 Scrap Tire Management Report, TDF had been the largest end market from 2013 to 2019. USTMA reports that cement kilns, pulp and paper mills, electric and industrial utility boilers and electric arc furnaces are some main areas that have used TDF.
Scrap tire consumption has been declining in the TDF end market for the past decade, though. Consumption of scrap tires decreased 15 percent in this end market between 2019 and 2021, according to USTMA.
Sheerin says some TDF users, such as electric utility boilers, are switching from using TDF to natural gas. “There are less opportunities for tire-derived fuel to be used in the electric and utility sector.”
He says the use of TDF by cement kilns and pulp and paper mills remained steady between 2019 and 2021.
In 2021, ground rubber took over as the largest end market for scrap tires. According to the 2021 Scrap Tire Management Report, ground rubber market increased by 29 percent in 2021 compared with 2019, and the market consumed about 28 percent of all scrap tires.
In the ground rubber end market, the use of scrap tires for molded and extruded products, such as rubber mats and flooring, increased use by 25 percent in 2021 compared with 2019, consuming 485,000 tons of scrap tires.
Rubber mulch increased use by 54 percent in 2021 compared with 2019, consuming 391,000 tons of scrap tires. USTMA estimates that home improvement activities during COVID-19-related shutdowns helped to increase use in this area.
“There was a boom in home improvement projects, and one type of home improvement projects is to put up a new playground for your kids or put mulch around the house,” Sheerin says. “So, we saw a very large increase in ground rubber for mulch. We think that will continue maybe not at the same rate as we saw in the last two-year period, but that mulch market is growing very, very steadily.”
Rubber-modified asphalt consumed slightly fewer scrap tires in 2021 compared with 2019, consuming 141,000 tons of scrap tires that year. Additionally, fine ground rubber consumed 79,000 tons of scrap tires in 2021.
USTMA says several other end markets reported increased consumption of scrap tires in its latest report. In 2021, civil engineering applications consumed about 6 percent of all scrap tires primarily for tire-derived aggregate.
According to Sarah Amick, senior vice president of EHS&S and senior counsel at USTMA, the organization currently is researching opportunities for tire-derived aggregate as well as insights on the economic and environmental performance of tire-derived aggregate. She says USTMA plans to release findings from its research on tire-derived aggregate in 2023.
Additionally, USTMA reports that the amount of illegally stockpiled scrap tires is down to about 50 million across the U.S. as of 2021. USTMA says it estimates more than 1 billion scrap tires were illegally stockpiled in 1990. There were about 56 million stockpiled scrap tires in the U.S. in 2019.
“This substantial reduction of over 95 percent is the result of decades of progress developing the scrap tire recycling industry and remediating stockpile sites,” USTMA says of this decrease.
According to USTMA, Texas stockpiles account for almost 24 percent of the total scrap tire stockpile inventory. Additionally, USTMA says about 11.5 million stockpiled scrap tires are spread across the country with four states—Washington, New Mexico, Virginia and New Jersey—exceeding 1 million stockpiled scrap tires.
“We’ve been very pleased that the states have continued working down those stockpiles, enforcing against people who are storing illegally,” Sheerin says.