The Federal highway program started in September 1956 with construction of an 8-mile section of U.S. Route 40 in Kansas, the beginning of a 13-year, 41,000-mile program. That same month Concrete Construction publishes its first issue. It's no small wonder that developments in concrete paving drew such considerable attention in the magazine's formative years.
An article about a quarter of a century later looked back on those years: “In the 1950s and 1960s the industry was concerned with the immensity of the Interstate system ... Production and high speed became the order of the day. The once coveted and often difficult mile-a-day paving became standard. Automation became the key word. Not only did the industry and its hardware grow in physical size, but more importantly, it grew into a sophisticated, technical industry.” (March 1982)
The July 1957 issue heralded an experimental 400-foot stretch of pavement that promised “a revolutionary effect” on highway construction methods: one of the first full-scale efforts to determine the adaptability of pre-stressing techniques to roads.
Connecting wire strands were anchored at opposite ends of the roadway and passed through flexible steel conduits embedded in the concrete. When the concrete was poured, a 6-foot gap was left in the middle of the section. When the concrete had set, the gap was jacked apart to a width of 8 feet to produce the required tension in the wire strands and compression in the concrete. Then concrete was poured into the gap. The slab was 5 inches thick.
A February 1958 article reported on a “traveling form paver” that operated on crawler tracks and could place a 24-foot-wide slab up to 10 inches thick. “So far used on a few projects in the Midwest, it permits rapid construction with a small paving crew to fairly accurate surface tolerances,” said the report.
According to a follow-up in December 1964, “factors such as lower manpower requirements and the impetus provided by the Interstate Highway System” helped advance slipform paving, which by then had been used in 25 states. The article said inventiveness and industry cooperation overcame early stumbling blocks, including limitation of the technology to nonreinforced slabs and questionable ability to conform to surface conformations and tolerances.
Early research to devise a practical way to top damaged or worn pavements with a thin layer (½ to 2 inches) of concrete had been frustrated by the difficulty of establishing a good bond between the old and new concrete. A July 1958 article presented a ray of hope: The success of thin-bonded concrete resurfacing on a badly scaled section of the Pennsylvania Turnpike had opened the door for other large-scale jobs.
However, progress was slow and a March 1974 report stated, “Until recently, no effective and practical means of resurfacing concrete slabs with a thin concrete overlay has been available.” The latest promise for the technique was fibrous concrete, then being tested in a full-scale, three-mile paving overlay test project in Iowa.
The second 25 years
A March 1982 article looked ahead to coming technologies such as computerized batching and laser controls. “Computers are becoming the brains of the concrete plant,” said the report. “Lasers are being used to control fine grading and paving machines. ... While still not ready for everyday use this technology will expand in the future.”
By the mid-1980s, most of the Interstate network was in place and fewer new highways were being built. Not to worry, said a May 1986 article. “The big news has come [in the Federal Highway Administration's] 4-R program—restoration, rehabilitation, resurfacing and reconstruction. This has now grown to be as big as the new construction program in both federal and local funds.”