Q2 2018

www.acpa.org Quarter 2, 2018 11 I O W A Innovations in the 1920s Result in Long-Lasting Roadways Historic US 20 in Iowa Boasts Long Life and Quality By Sheryl S. Jackson ACCORDING TO THE HISTORIC ROUTE 20 ASSOCIATION, US 20 is the longest route in the US—3,365 miles from Boston, Mass., to Newport, Ore. In 1926, 333 miles of roadway was designated as US 20 in Iowa. There were, however, a few sections of this “superhighway” built before it was officially known as US 20, and two sections of concrete pavement have served the traveling public since their construction in the early 1920s. A 14-mile stretch of old US 20 from Sioux City to Moville was paved in 1921 by C.F. Lytle. The 8-in. thick concrete pavement handled traffic in the area with no major reconstruction or repairs until 2017, when it was overlaid with asphalt. “The original pavement may be covered, but it did not fail and is still there as a foundation for the overlay—supporting traf- fic as it has since 1921,” says Todd Hanson, P.E., engineer with the Iowa Department of Transportation. Another stretch of old US 20—nearly one mile in the city of Moville—still has concrete as the driving surface. The concrete pavement was originally built in 1922 and is an 18-ft wide road constructed of 8-in. thick concrete. There are a number of theories about the long life of both pavements, says Hanson. This was new construction, so the contractor began by scraping the ground to form the roadbed and then laid concrete directly on the » continues on page 12 Photo Credit: Iowa DOT