ACPA Quarter 3 2018

Concrete Pavement Progress www.acpa.org 12 H I S T O R I C A R K A N S A S R O A D Today, Hwy 296 primarily carries local traffic such as passenger vehicles and trucks from local farms, says Steve Frisbee, PE, district engineer, Arkansas Department of Transportation. “The average traffic count for the road is 1,300 per day,” he says. “It has required little maintenance throughout the years.” Recent assessment of the road and pavement core samples yielded some surprising results. “The pavement thickness was found to vary with distance from the edge,” says AlanMeadors, P.E., Arkansas promotional director for the Oklahoma/ Arkansas Chapter-ACPA. “The cores and field inspection loosely verify that the original typical section called for 18-ft-wide pavement with 9-ft lanes and with 9 in. depth at each edge, then sloping to 6 in. in the middle. The joint spacings were 50 ft, which is much more than current designs that are typically 15 ft. in Arkansas,” he says. “Most of the slabs were cracked in the middle because of the spacing, but maintenance efforts to seal the cracks years ago helped extend the life of the pavement.” “One of the core samples broke at an incredible 13,300 psi,” says Meadors. “The surprising part of the cores was the size of the aggregate.” Gravel ag- gregates that exceed 2 in. in diameter were used in the concrete, and the cores showed no signs of any durability issues after 89 years, he adds. “It amazes me that concrete produced 89 years ago—when there was little knowledge of aggregate grading, air entrainment or quality control test- ing—could still be in service today.” According to documents submitted for nomination to the National Register of Historic Places, the original contractor for the 1929 section of the high- way was McGuire & Cavender of Texarkana, Texas. It was constructed as a Bates Type pavement, which includes welded wire reinforcement in the concrete. Some parts of the wire are visible in some of the pavement surface. “Newer” Section Still Serves Area In 1954, when upgrades to US 67 were necessary, rather than renovate the 1929 pavement, the state highway department built a new section of the highway adjacent to the Old US 67 section.This allowed contractors to take advantage of new engineering practices that allowed for more expedient avenues to be built. Much of the current Highway 67 follows the original route and has been upgraded over time. This newer, 64-year-old concrete pavement is also original pavement that has only required routine maintenance, says Frisbee. Although the road routinely handles 3,300 vehicles per day, including 250 large trucks, a number of rehabilitation projects for nearby I-30 were going to close lanes and so, US 67 was identified as an alternate route to avoid traffic congestion. US 67 maintenance efforts have involved replacing asphalt shoulders and patching and sealing concrete pavement joints to prepare for temporary increases in traffic was performed. Prior to preparing the pavement for additional traffic, the pavement required little attention, Frisbee says. Beyond serving as a critical highway for traffic diverted during I-30 con- struction, Frisbee says the 12-in. pavement is critical to the area. “Some of our I-30 bridges are low, so trucks that are over 16 ft high must use US 67. This means that trucks that weigh 100,000 lbs. or more travel the road,” he says. “This 1954 concrete pavement is a real workhorse for us.” » continued from page 11