Q1 2018

Concrete Pavement Progress www.acpa.org 6 F R O N T C O V E R IN 1947, A 10-MILE SECTION OF HIGHWAY, originally designated US 70-99, was built as a rural four-lane highway fromOntario to Colton, California Seventy years later, the highway sec- tion, now part of the bustling Interstate 10, plays a vital role in California’s Inland Empire, the state, and the nation. That would be a remarkable feat for any pavement, but considering this highway section is only ap- proximately 8 in. thick, the story becomes even more intriguing. “It is amazing that the road has survived this long, especially with the volume of heavy truck traffic that it handles,” says Michael Ristic, P.E., Senior Transportation Engineer, District 8, California Department of Transportation. In 1993, the stretch of I-10 in Ontario, California carried 90,000 vehicles per day—today, the volume is more than 280,000 vehicles per day, which in- cludes a much higher percentage of large trucks. “For a comparable road today, we expect a 12- to 14-in. concrete pavement to last 40 years.” Steel tie-bars were used to prevent the lanes from separating and to reduce cracking. “While there was some use of tie-bars in the 1940s, [the technology] was not used from the 1950s to 1970s, but now it has become standard practice again,” says Ristic. He also believes that the quality of material and the likelihood that the concrete could cure in place for roughly five months before it opened for traffic has contributed to the pavement’s long life. The pavement also holds the distinction of being the first highway section to be diamond ground, whichwas a revolutionary processwhen it was first treated in 1967. “This was the first site of diamond grinding in the nation,” Ristic said, adding, “It was repeated on the same pavement sections in the 1980s, in 2000 and in 2016,” he explains. “Actually, the 8 in. of concrete pavement is really now only 7.5 in.” Even with the thinner concrete layer, only about 25 percent of the original pave- ment has been replaced over the years, he adds. The Highway Pavement That Beat the Odds By Sheryl S. Jackson CAL I FORN I A I -1 0 continues on page 8 »