US 181 Harbor Bridge Replacement Project

Location: Corpus Christi, Texas

Award: Innovative Applications

Project Team

Owner: TxDOT

Contractor: Flatiron/Dragados LLC

Concrete: Texas Concrete Co

Slag Cement: Texas Lehigh Cement Company and Skyway Cement Company

Located in Corpus Christi, Texas, the US 181 Harbor Bridge Replacement Project is a massive 1.3 billion dollar coastal infrastructure undertaking. This project is designed for ultimate resilience, engineered to withstand the harsh marine environment of the Gulf Coast, including constant exposure to sulfates, chlorides, and cyclic wetting and drying.

To meet these extreme demands, the team utilized over 42,000 cubic yards of high performance concrete. Slag cement was a strategic necessity for this build, integrated at replacement levels between 35 and 50 percent for paving, structural elements, and massive pylon foundations.

The use of slag cement was vital for managing the intense heat generated during the curing of these massive structural pours. In the sweltering Texas summer heat, slag provided cooler hydration temperatures and extended the working time for crews, while significantly improving the pumpability and finishability of the mix.

The results of this specialized blend are staggering. While meeting strength requirements up to 7,000 psi, the inclusion of slag cement helped reduce the permeability of the concrete and is projected to extend the service life of the bridge by an estimated 30 to 50 years compared to straight cement mixes. In fact, the total service life for this structure is estimated at an incredible 170 years.

Beyond the mechanical benefits, the use of slag cement reduced the embodied carbon of the core concrete by up to 40 percent. Combined with high tech features like embedded geo sensors to monitor curing in real time, the Harbor Bridge project proves that slag cement is the backbone of durable, sustainable, and long lasting coastal infrastructure.

Application Type

Application Type	Roadway paving, coastal retaining structures, flatwork, soil stabilization, utility trench backfill CLSM.
% Slag Cement Replacement	35–50%
% Portland Cement	50–65%
% Portland Limestone Cement
% Other SCM (if applicable)
Aggregate	Texas Gulf Coast blend – river gravel + manufactured sand
Water/cement ratio	0.38–0.45 depending on placement category
7-day strengths	3,500–4,800 psi
28-day strengths	4,500–7,000 psi