Froedtert Hospital Blue Parking Structure

Location: Milwaukee, Wisconsin

Award: High Performance

Project Team

Owner: Froedtert Hospital

Contractor: CG Schmidt

Architect: EUA – Milwaukee

Engineer: Graef

Concrete: Riv/Crete Ready Mix

Slag Cement: St Marys Cement

 Located in Milwaukee, Wisconsin, the Froedtert Hospital Blue Parking Structure is a five-story facility providing 2,400 parking spaces designed to enhance the experience for patients, visitors, and staff. This thoughtful design includes a climate-controlled pedestrian bridge, accessible parking near elevators, and critical safety and sustainability features.

For a massive post-tensioned structure like this, the construction schedule lived and died by early strength gain. The team utilized a slag cement replacement rate that was specifically optimized to hit 3,000 psi in just 20 hours. This allowed for a rapid and consistent post-tensioning sequence, ensuring the project stayed on track while still comfortably exceeding the 28-day requirement of 6,000 psi.

Slag cement was the clear choice over other supplementary materials because of its remarkable consistency. Even with a complex chemical cocktail of admixtures, including corrosion inhibitors and viscosity modifiers, the slag-based mix remained stable and predictable. This reliability was crucial for the team as they used maturity meters to time their post-tensioning across variable weather conditions over the multi-year build.

The thixotropic properties of the slag mix also improved pumpability, which was essential for a project that occasionally required multiple pump stages to reach the upper levels. By reducing permeability and ensuring consistent air entrainment, slag cement has provided the foundation for a structure designed with a 75-year service life. The Froedtert Blue Parking structure stands as a premier example of how slag cement delivers the precision and durability required for high-stakes healthcare infrastructure.

Application Type

Application Type	Slab mix	Exterior Columns & Shear Walls
% Slag Cement Replacement	15	10
% Portland Cement
% Portland Limestone Cement	85	80
% Other SCM (if applicable)	Carbon Cure; VMA, CI, Super, Mid-Range, AE, Hyd. Stab.	Fly Ash (10)
Aggregate	Combined Aggregate: ¾ gravel, 3/8 pea stone & sand; for pumpability & workability	Combined Aggregate: ¾ gravel, 3/8 pea stone & sand; for pumpability
Water/cement ratio	0.38 typ (max 0.4 per ACI F3)	0.40
7-day strengths	5700 psi, 3000 psi @ 20hr for PT	5200 psi
28-day strengths	6000 psi required, 7300 psi typical	5000 psi required, 6500 typical