"K.C. Missouri put down on a heavy traffic street [poured] fly ash 30+ years ago. Was still in great shape, but city tore it up this summer. My next house will be fly ash. If any humans are left in 4000, my house will probably still be standing... "Lasts so much longer, than asphalt, that needs replacing every 2-3 years in heavy traffic. I figured if the did this on rural Kansas roads, then it would create a road or bridge that would last for 20+ years, so money could go for high traffic city areas, that need fly ash even more."