by Stacey Epps
In the realm of modern infrastructure, bridges serve as lifelines, connecting communities and fostering economic growth. As the world faces increasing environmental challenges, the construction industry is under pressure to adopt sustainable practices without compromising on performance and resilience. In this context, Ultra-High-Performance Concrete (UHPC) emerges as a game-changer, offering unparalleled durability and sustainability in bridge applications.
One recent project exemplifying the practical application of UHPC in bridge construction involved a successful collaboration between M&J Engineering; Mohawk Northeast, Inc.; Close, Jensen, & Miller, P.C. (CJM); and the Connecticut Department of Transportation (CTDOT). Stretching an impressive 876 feet over the Housatonic River, the Devon Bridge required comprehensive rehabilitation. This project scope presented the opportunity to use UHPC as a roadway wearing surface, a first in the state of Connecticut. Typically, UHPC on bridge decks is covered by hot mix asphalt, so the workability and final appearance are not prioritized. However, for this project, the flow of material and aesthetics were of vital importance.
UHPC application
Collaboratively, the team revised the mix design to enhance field installation, focusing on increasing viscosity and reducing steel micro-fibers by 1%. Following the finalization of the optimized mix design, a series of trial batches were formulated and tested at Mohawk’s facility. These trials ensured not only the viability but also the exceptional quality of the revised mix for seamless field installation.
“The contractor performed the concrete work locally in their shop, and experienced issues with the initial trial mix,” said John H. Miller II, P.E. L.S. from CJM. “They experimented with unique constructability techniques and worked closely with their vendor to modify the working drawing design mix. A more thixotropic mix was developed, and together, the team was able to successfully achieve a partially filled UHPC, partially-filled steel grid deck with low permeability and anticipated exceptional long-term durability, consistent with the goals for this project.”
The project’s success showcases how UHPC can make a big difference in bridge construction. Here’s why it matters:
- UHPC boasts exceptional resilience against corrosion, abrasion, and seismic events, with compressive strengths exceeding 21,000 psi and tensile strengths surpassing 1,700 psi.
- Its durability leads to extended service life and reduced maintenance requirements, conserving resources through efficient design and longevity.
- UHPC’s reduced carbon footprint, due to less cement usage, contributes to lower greenhouse gas emissions and energy consumption.
- Its high strength-to-weight ratio enables the fabrication of precast components, minimizing construction waste and facilitating off-site manufacturing.
- UHPC supports innovative bridge designs, allowing for longer spans, slimmer profiles, and compatibility with advanced construction techniques, ultimately enhancing resilience and sustainability while offering community benefits such as reduced noise pollution.
As the demand for resilient infrastructure grows in the face of climate change and urbanization, UHPC emerges as a cornerstone of bridge engineering, paving the way for a more sustainable and resilient future.
Stacey Epps
Stacey Epps, vice president of the New England Bridge & Highway Division, leads M&J Engineering’s CE&I teams through bridge, heavy highway, and civil construction projects.
