Gateway Expressway Cuts CO2 Through Material Selection and Reduced Congestion
According to the Texas A&M Transportation Institute, 2021 Urban Mobility Report, June 2021, prior to 2020, nearly 3.5 billion gallons of fuel was wasted annually due to traffic congestion in the U.S., with 20% of that attributed to heavy trucks. In Clearwater/St. Petersburg, Florida, the new Gateway Expressway will help to lower CO2 in two ways: through the use of innovative concrete mix designs and by reducing traffic congestion.
Portland-limestone cement (PLC) and supplementary cementitious materials (SCMs) are being used for most of the concrete mix designs other than precast elements. PLC can have up to 10% lower CO2 associated with its production while providing the same performance as ordinary portland cement (OPC). And SCMs like fly ash and slag also significantly reduce the CO2 footprint of mixtures, often while improving fresh or hardened properties of the concrete. Structures for the Gateway Expressway are owned by FDOT, which encourages the use of PLC in all their projects for the sustainability benefits. The cement must undergo rigorous testing and be approved prior to use. The ready mix concrete supplier provided mix submittals to contractors and convinced them to use PLC for both the sustainable and performance aspects of the material. In total, the Gateway Expressway will require more than 79,119 cu yd of concrete and be exposed to both normal and aggressive environments.
As a result of this project, comprising several pieces, traffic congestion will be reduced, saving fuel and improving air quality, which drivers and residents alike can appreciate:
Two new 2-lane elevated tolled roadways are being built to provide direct connections between US 19 and I-275, and the Bayside Bridge and I-275. The new bridges and pavement are part of SR 690, a new 4-lane tolled expressway connection, which will be built in an existing median. Because space is limited, SR 690 will be elevated over portions of streets below it.
SR 686A, a new 4-lane elevated tolled expressway from the Bayside Bridge to just west of I-275. It will be primarily built in the median of Roosevelt Boulevard and includes interchange upgrades, too. The new roadway will continue south through the old Sunshine Speedway property until it merges with SR 690.
A portion of I-275 will be widened to add a toll lane in each direction along the median next to the existing lanes.
Work on the nearly $600 million project is expected to be completed in early 2023.