72 HOURS ‘TIL DEPARTURE: PAVING YEAGER AIRPORT Project Specifications The CRW project followed the Federal Aviation Administration (FAA) P-401 specifications, utilizing Superpave 19-mm mixtures with coarse and fine limestone aggregates and a small fraction of natural sands. The mixtures were designed at 75 gyrations with a PG 64H-22 (PG 70-22). To meet the tight 72-hour time frame for the final paving, WV Paving utilized two local plants located in Dunbar and Poca, roughly 15 and 20 miles, respectively, from the airport. Each plant was dedicated to its own paving crew, which consisted of a materials transfer vehicle followed by a paver setup for 26 feet and three rollers performing compaction. WV Paving employed 85 trucks, 35 of which were dedicated to milling operations and the remainder dispersed between the two asphalt plants to ensure smooth operation during both day and night shifts. In front of the two pavers, WV Paving utilized four milling crews equipped with GPS and laser leveling systems to complete the roughly 123,000 square yards required to complete the two-inch mill and fill section and the other areas and tie-ins. All milling operations were completed in 16 hours. After the milling, WV Paving used an echelon paving operation to place roughly 23,000 tons of asphalt materials in just 54 hours. This helped WV Paving meet the strict time restraints and reduced the number of longitudinal joints that had to be saw-cut, improving the overall joint quality and appearance. After paving was complete, the asphalt was required to cure before being grooved and permanently striped. The final project stage required rigorous quality control checks throughout the production process, notwithstanding the time constraints. This required 13 lots consisting of 59 materials samples, and over 5,000 survey points to verify the elevation of the runway during the milling and paving processes. After completion of the overlay, a final survey confirmed that the entire runway was within the specified half-inch elevation tolerance. While profilograph roughness was not required, quality control data revealed that the runway had exceptional smoothness, with an overall average International Roughness Index reading of 66.5 inches per mile. While Percent within Limits (PWL) can be a challenging specification, WV Paving came to this project well prepared, as the WV Division of Highways utilizes a similar specification on all its National Highway System routes. The FAA required that each lot’s pay factor be determined by taking the lowest computed pay factor (based on either laboratory air voids and in-place density), all while meeting strict government specifications. Pay Factors for each lab air voids, and in-place density (mat and joint) were based on the statistical percentage of material within their given tolerances, which is calculated with the sample mean and standard deviation of the property. Air voids tolerances were between 2–5%, with the in-place mat density lower threshold being 92.8% △ continued from page 19 20 SPRING/SUMMER 2024
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