Bridge deck paving on the Chesapeake Bay
Sep 15, 2020
“The team at Advanced Materials Services, LLC, makes mix designs that work,” said Rob Schwear, area operations manager at Allan Myers Paving based in the Mid-Atlantic. “They’ve worked on some of the most well-known racetracks in the nation and we were excited to pave one of their designs when it came time to work on the bridge deck of the Chesapeake Bay Bridge and Tunnel.”
Bridge deck paving can be challenging
Bridge-deck paving can be difficult for various reasons. Temperature is important because bridge-deck mixtures are usually a high-polymer, dense-graded 9.5mm mix over concrete and the temperature spread between the ambient temperature and bridge’s surface temperature can be upwards of 20 degrees Fahrenheit (F). In addition, there are many expansion joints and the mix must usually be static rolled since no vibratory rollers are permitted.
The famed bridge-tunnel
The CBBT is a 17.6-mile engineering marvel that carries travelers across the Chesapeake Bay and connects Virginia’s eastern shore with the mainland in Virginia Beach. When a portion of the bridge-tunnel needed repaving, the Chesapeake Bay Bridge & Tunnel Commission managed the project.
The safety of the Commission’s customers, the traveling public, is paramount and the desired project outcome was simple: a flexible, smooth ride. Since one pothole can lead to traffic delays, The Commission called on the best to design the asphalt mixture that would be used.
Mix design is essential
For many in the race car world, Brian Prowell, Ph.D., P.E., of Advanced Materials Services is known for making mix designs that perform on race tracks across the U.S. The company also has successful experience with highway mix designs, which have a similar need for smoothness, durability, uniform texture and the high-quality materials to help ensure compaction and performance.
The Commission worked with Advanced Materials Services to create a mix design well-suited for the CBBT bridge-deck. While warm mix wasn’t explicitly part of the specification, using a compaction aid and antistrip was required.
The only thing left to do was pave with the right team and the right product. Enter the Allan Myers paving team, who wields a strong reputation of quality in their region, has experience with bridge-decks and knew how to get the compaction and antistripping properties needed.
“When we were awarded the project, we had experience with Evotherm® and knew of the effectiveness of warm-mix additives to serve as both the compaction aid and antistrip,” said Schwear. “We trusted the Ingevity team and their product to help us build a bridge deck that met The Commissions specification.”
The Allan Myers team
Allan Myers has an 80-year history as the largest self-performing civil contractor and materials supplier in the Mid-Atlantic. Their team is well known throughout Pennsylvania, Maryland, Delaware and Virginia, producing around 3.6 million mix tons annually. The paving responsibility on the project was led by senior project manager, Chris Selph, and Schwear, a 24-year veteran of the company. The team had used Evotherm in multiple locations across the states where they operate previous to the CBBT project and leaned on Ingevity’s trusted product and team to get the job done.
Paving of the bridge-deck was completed in multiple sections. The first section of approximately 24,000 tons began in the fall of 2019, the second was paved in the spring of 2020, and the final section completed in the summer of 2020. Temperatures behind the screed began around 300 F, a significantly lower-temperature environment compared to those using Rosphalt® additives or other highly heated polymer or rubberized alternatives that occur at upwards of 400 F.
“Evotherm played a role in allowing us to continue to work into the fall season of 2019 to complete a significant portion of the project,” explained Schwear. “We finished up earlier this spring and everyone – the CBBT, our crew, drivers – is pleased with the outcome.”
Thanks to the Commission, Advanced Materials Services, Allan Myers and Ingevity, the experience for travelers crossing the CBBT above is the same as the boats, vessels and watercraft below: smooth sailing.