UHPC Solutions sets new Holcim Ductal watermark on Delaware crossing

Sources: Saint-Gobain Construction Chemicals, Alpharetta, Ga.; CP staff

Crews from New Jersey-based UHPC Solutions North America closed out 2023 placing and finishing Holcim Ductal ultra-high performance concrete on the third and final phase of a 14-month deck rehabilitation for the 13,500-ft. Delaware Memorial Bridge, whose twin suspension structures link Wilmington, Del. and Salem County, N.J. over the Delaware River. In partnership with UHPC Solutions and Ductal US, a technical team representing Saint-Gobain Construction Chemicals’ Chryso and GCP brands helped identify the high-range water reducers and other admixtures best suiting fiber-rich concrete mixes developing compressive strengths above 18,000 psi—three times the design strengths typical of bridge deck concretes. The Ductal schedule for the three phases totaled 5,000 cubic yards. 

“This project is the first of its kind in the United States. It is the first suspension bridge to have a UHPC overlay, the largest UHPC project, and broke records for UHPC placed in a single day,” says UHPC Solutions NA Director Gil Brindley. “Its success is due to the partnership of all involved. From the owner and designer, material suppliers and subcontractors, to the workforce, everyone played an important role and worked collaboratively to make this project a reality.” 

Along with contributing to strength development and binder optimization, the Chryso and GCP admixtures yielded a mix consistency enabling UHPC Solutions crews to place and finish in a downhill direction, unusual for a concrete paving train. Construction schedules were confined to low traffic windows.

The Ductal specification stemmed from a life cycle cost analysis the Delaware River & Bay Authority performed as it weighed existing bridge deck repair or replacement options. The LCA pegged savings of $65 million over a 50-year service life for the Ductal solution. The UHPC mixes were to form a new 2- to 3-in. overlay system along the length of the twin crossings to both protect and structurally strengthen their existing concrete decks. The specification likewise offered significant construction time and cost reduction potential for a structure whose daily traffic load approaches 100,000 vehicles.   

“The use of UHPC on the Delaware Memorial Bridge deck rehabilitation project was the perfect fit, offering speed and light-weight durability,” affirms Saint-Gobain Construction Chemicals North America President Steve Williams. “We were pleased to apply our admixture technologies to customize the UHPC, so that it met all performance needs and ensure that it will stand the test of time.”