Florida Study Tested Ash In Road Construction

Researchers monitored groundwater near a test roadway built with incinerator bottom ash over ten years.

Updated on Oct. 4, 2026 in Construction

Isometric editorial illustration showing a multi-layered road sub-base built of aggregate, glass, and ceramic fragments with a clean groundwater monitoring pipe. — Florida researchers concluded a decade-long study confirming that using municipal solid waste incinerator bottom ash in road construction does not harm groundwater quality. AI Illustration. Upload story photo >

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Would you support using recycled incinerator ash in road construction projects in your area?

Florida researchers concluded a ten-year study in 2024 evaluating the use of municipal solid waste incinerator bottom ash in road construction. The project found that utilizing the ash in road structures does not negatively impact underlying groundwater quality.

Why it matters

The study aimed to provide real-world field data to determine if incinerator ash can safely serve as a construction material, supplementing existing laboratory tests and predictive models.

Municipal solid waste incinerators in the United States burn over 30 million tonnes of waste annually, reducing total volume by approximately 90 percent. Groundwater samples from the ten-year Florida study showed no consistent increase in aluminum levels.

The details

The project team utilized computer modeling to predict metal leaching through soil before receiving an environmental permit for the site. The pilot roadway successfully incorporated bottom ash, which consists of slag, glass, concrete, and ceramic fragments, into its base layer, asphalt, and concrete components.

Researchers began the ten-year groundwater monitoring project in 2014.
Groundwater monitoring occurred at the test roadway site from 2014 to 2024.
The ten-year groundwater monitoring study concluded in 2024.

Market Landscape

This research aligns with global efforts to repurpose waste by-products, following a pattern set by the European and Asian regulatory standards for ash reuse. By verifying safety through field testing, the project helps position recycled incinerator ash as a viable alternative to virgin aggregates in the construction sector.

Residents in the area can expect continued safety as the study confirms that utilizing incinerator bottom ash in road structures does not affect local water quality. This finding potentially opens the door for more sustainable and cost-effective road building materials in future infrastructure projects.

The takeaway

The successful integration of bottom ash into road components demonstrates that recycling waste streams can offer environmental benefits without compromising public water safety. These results provide a necessary foundation for state agencies looking to update their approved construction materials.