WWW.ACPA.ORG 19 FALL // 2024 COVER STORY Concrete is not typically used on non-interstate projects in Kentucky, but the engineering firm Gresham Smith opted to use concrete because it would eliminate the seam that would otherwise have been required between asphalt lanes and concrete in the gutter pan and bike lanes. In the concrete-paved roundabout lanes, joint lines follow the travel lanes, improving safety. Another safety enhancement associated with concrete is its reflectivity, which improves visibility at night. Concrete offered a durable option, since asphalt would have required resurfacing every 5–10 years, while concrete pavement can be treated with minor preservation techniques much less frequently. Given the complex elevation transitions of the roundabouts, reducing the need for repair was vital. Less maintenance also means fewer disruptions to traffic, lowering the emissions associated with traffic delays. Another sustainability advantage associated with concrete is carbonation; the chemical reaction between CO2 in the air and calcium compounds in the concrete forms carbonates and sequesters the carbon. The KY 9 project was completed in 2018, won a 2019 American Concrete Paving Association Excellence in Concrete Paving Award and won the 2021 ACEC Kentucky Grand Conceptor Award. Photos courtesy of Gresham Smith.
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