Greener Cement Contributes to a Healthy Hospital, and a Healthier Planet
Dedicated to Patient Health, New Hospital Is Better for the Planet, Too
Faced with the need for more bed space to serve the community of North Liberty, Iowa, the University of Iowa Hospitals opted for a concrete building for occupant safety and the overall long-term benefits of concrete’s durability. The six-story, 469,000-square-foot mid-rise building will provide additional capacity for transfer patients, medical care, and learning and training purposes.
Owners also considered the project schedule in choosing concrete. Construction delays are rarely desirable and generally not acceptable. Given the demand for the extra facility space, adhering to the 24-month-long project schedule was an important consideration.
Modern buildings are divided into three categories. Low-rise is generally one to three stories; mid-rise is four to seven; and high-rise is typically beyond seven stories. Fewer than 1% of buildings are greater than 15 stories. While the vast majority of buildings are still in the low-rise range, mid-rise represents about 6% of all buildings. Mid-rise construction strikes a good balance between low-rise and high-rise buildings. With low-rise, owners don’t get as much density out of their project as might be needed. Even in less populated communities, the cost of land is still a significant consideration. With high-rise, the structural engineering requirements add complexity to design compared to shorter structures.
One Cement, Many Concrete Products
Portland-limestone cement, or PLC, is a general-purpose binder. All 30,000-cubic yards of concrete products used for the UI Hospital are made with the same PLC, an ASTM C595 Type IL cement. PLCs are a proven technology for reducing the carbon footprint of concrete by up to 10%. As climate change unfolds, the cement and concrete industries, like many others, are offering solutions to reduce their carbon footprint, a measure of the impact of greenhouse gases on the environment, expressed as GWP, or global warming potential. Blended cements, like PLCs, are readily available throughout the U.S. to help designers and specifiers meet their sustainability objectives.
On this project, concrete is being used in cast-in-place, precast, and post-tensioned products, in applications ranging from foundations to floor slabs, columns and walls for the building, as well as for its parking lot. In these applications, concrete’s durability aspects were most critical. Exposure conditions include freeze-thaw, deicers, and potentially alkali-silica reaction, or ASR.
At the North Liberty site, concrete is placed by pump and finished by machine. Pump operators demand consistent properties to move material from the hopper to its final place of deposit without interruption. This includes stability to handle the pressure of pumping without segregation. Inconsistent mix properties, like slump, can put a real burden on pump operators and placing crew. It speaks to the viability of PLC mixes that they can meet the in-service needs of the structure as well as the placing criteria. Concrete is being conventionally cured with membrane-forming curing compounds.
General Benefits of Concrete for Hospitals
There are other reasons to choose concrete for healthcare facilities. Concrete is an inert substance and does not off-gas harmful chemicals. Its modulus of elasticity, a measure of its stiffness, is extremely high, so it reduces vibrations in buildings, which can be beneficial where sensitive medical equipment operates.
Project Team
General Contractor: JE Dunn Construction Group
Architect: Neumann Monson Architects
Concrete supplier: Iowa City Ready Mix
Cement supplier: Summit Materials
This case study was provided by Summit Materials. For more information, feel free to send any inquiries to our project contact.