The Economic Times

In 1977, Pennsylvania tested an 800-foot road base made with power-plant scrubber sludge; its strength rose from 720 to 1,014 PSI over seven years

A Pennsylvania road base demonstration in 1977 used FGD scrubber material successfully. This material, combined with lime and ash, endured severe weather for seven years. Similar projects followed in Florida, Texas, and Ohio with positive results. These roads showed increased strength and durability over time.