For three quarters of a century, the Hoover Dam has been celebrated as a marvel of American concrete construction and design. On Sunday, World of Concrete attendees got an up-close look at the highway project that's transforming the national landmark.

For the third annual Editorial Tour, participants veered off the paved road to the Hoover Dam Visitors Center and traveled to the Arizona side of the jobsite for a unique view of the bridge being built over the Colorado River. The bypass project—about 1500 feet downstream from the dam—is designed to help alleviate traffic that has for decades snarled around the Hoover Dam and caused headaches for area residents and visitors.

Shortly after arriving at the bypass jobsite, Jeff St. John, deputy project manager with contractor Obayashi/JSM, delivered a project update and answered questions. "We've been able to cast all of the precast column segments," he said. "We're using a self-consolidating concrete mix that is about 800 pounds of cement and 200 pounds of fly ash."

The bypass is expected to cost $114 million, but the extensive auxiliary work will add to the overall price. "With all of the additional paving work, it'll probably end up costing the government $300 million for the entire project," St. John continued.

Completion was pushed back when, in September 2006, 60-mph winds lead to a cableway collapse. The bypass is now expected to wrap up and open for traffic in the summer of 2010. "We've been set back about a year and we're about a week away from having the cable system operational again."

In addition to the exclusive bypass tour, Luke Snell provided a brief history and perspective on the Hoover Dam's groundbreaking construction 75 years ago. "The dam was named after Herbert Hoover, not because he was the president during the time of its construction, but because he represented the federal government under President Warren G. Harding during initial project discussion," he said. "Six companies, who formed alliances, won the bid for the dam project and they were required to place 3.4 million cubic yards of concrete."

Participants also received a guided tour of the power plant that turns the Colorado River into much-needed electricity. After descending 530 feet underneath the structure, attendees walked through the original tunnels from the 1930 construction and deep into Black Canyon. The group was led to one of the 30-foot-diameter pipes that transport 90,000 gallons of water to the hydroelectric generators. Before riding the elevator back to the surface, the tour ended with a peak at the massive generators behind the scenes of the dam.

"This project is the granddaddy of concrete projects," summarized Snell. "It changed the way we do everything today."

Attendees also received commemorative hardhats and reflective visors, courtesy of tour sponsor Sika Corp. (Booth S10107), as well as a boxed lunch.