A deck repair project administered through the Maryland Transportation Authority (MdTA) at the Baltimore Harbor Tunnel on I-895, was recently completed by Swank Construction Company from New Kensington, PA. A major focus of the job was the restoration of the driving surface slab within the Harbor Tunnel. Both driving lanes through each tube of the tunnel were rehabbed. This was a two-year project that began in 2019 and concluded in 2020. The total amount of improvements was just under 50,000 square yards.
The Northbound lanes were closed in early April 2019, and traffic was diverted into the Southbound tube during the temporary closure, with single head to head traffic in each direction. A 60-day closure was permitted for the work.
Then in April 2020, traffic was closed in the Southbound tube and diverted to the Northbound lanes in similar fashion, with head to head traffic and another 60-day allowable closure period.
The removal depth of the surface was 2” inside the tunnel by a combination of milling and hydrodemolition. The reinforced approach pavement leading into the tunnel included up to 6” of removal, plus a new mat of stainless steel rebar was added. Latex Modified Concrete (LMC) was used to resurface the 9,219 feet x 22 feet of travel lanes in each direction. HTNE Hydrodemolition Services, LLC, performed the hydrodemolition work.
The Northeast Division of Modified Concrete Suppliers, LLC, from New Kensington, PA, produced the LMC. Modified produced over 4,400 cubic yards of High Performance Latex Modified Concrete for the two phases of work. This included 2,155 cubic yards of LMC in the Northbound tube, and 2,283 cubic yards of LMC for the Southbound tube.
A preferred strategy to bridge deck preservation by many agencies is “Fast Track” Hydrodemolition. This includes milling for depth and detailing the last ½” of cut with hydrodemolition. This gives the best possible surface preparation, while selectively removing all deteriorated or weakened concrete in the existing deck. After clean-up and deck washing, a highly bondable High Performance LMC Overlay is placed. This can be placed as thin as 1 ½” in thickness, and even inlayed in order to maintain grade and minimize the removals to only selective removal of the weakened or deteriorated concrete. Hydrodemolition surface preparation allows the LMC to create a long term, monolithic attachment to the remaining deck or surface. This type of construction will provide a long lasting, structural bond that leads to a protective wearing surface and deck protection extending out beyond 25 years in many cases. On brand new decks, installations of Latex Modified Concrete have performed upwards of 40 years. The Maryland Transportation Authority continues to be a leader in the use of LMC Overlays to preserve and protect their tolled facilities. The preservation work is done fast, economical and extends the service life of their bridges and tunnels for over 25 years.