Illinois expressway used coal fly ash in 1972; monitoring found no major issues

In 1972, a groundbreaking Illinois expressway project utilized coal fly ash for highway embankment fill, showcasing remarkable structural integrity over time. Vigilant monitoring revealed no concerns with settlement, frost heave, or groundwater. This successful initiative not only prompted other states to adopt fly ash recycling standards but also demonstrated that industrial byproducts can effectively substitute natural aggregates in construction endeavors.