Chryso, GCP admixtures propel UHPC Solutions’ Ductal record

Crews from New Jersey-based UHPC Solutions North America closed out 2023 placing Holcim Ductal ultra-high performance concrete on the third and final phase of a 14-month, 5,000-yd. deck rehabilitation for the two-mile Delaware Memorial Bridge. In partnership with UHPC Solutions and Ductal US officials, a technical team from Saint-Gobain Construction Chemicals’ Chryso and GCP brands helped identify high-range water reducers and other admixtures best suiting fiber-rich concrete mixes developing compressive strengths in excess of 18,000 psi—three times the design strengths typical of bridge deck concretes. Along with HRWR agents contributing to strength factors, the Chryso and GCP agents yielded a mix consistency enabling UHPC Solutions crews to place and finish in a downhill direction, unusual for a concrete paving train.

“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.”

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 Delaware Memorial Bridge 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 future of UHPC in construction is bright,” affirms Saint-Gobain Construction Chemicals North America President Steve Williams. “Greater strength, with less material needed and longer service life of more than 50 years, makes UHPC a key component in the sustainability goals of the construction industry. The use of UHPC on the Delaware Memorial Bridge deck rehabilitation project was the perfect fit, offering speed and light-weight durability. 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.”

“Holcim US and Ductal are excited to bring our innovative UHPC solution to this signature bridge project,” adds Ductal US Technical Manager Greg Nault. “Chryso and GCP’s specialty admixtures continue to work exceptionally well in our ultra-high performance concrete products and allow us to cultivate new innovations for the construction industry.” — Saint-Gobain Construction Chemicals, Alpharetta, Ga.,,


The Interstate 295/Delaware Memorial Bridge’s twin suspension structures link Wilmington, Del. and Salem County, N.J. over the Delaware River, carrying daily traffic upwards of 100,000 vehicles. New UHPC deck work could only be performed during lower traffic volume intervals. Contractor UHPC Solutions North America deployed portable Mixer Systems batch equipment for Ductal materials delivered in 1-yd. supersacks, dosing Chryso and GCP admixtures from totes.
Mixer Systems customized a batch plant to pace the Ductal mix production rate that UHPC Solutions crews required.