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Great American Insurance Building
Project Name: Great American Insurance Building at Queen City Square, Cincinnati, Ohio
Project Description: A 6’ mat foundation slab containing 6,000 cubic yards (cuyds) of concrete for the 40 story insurance building. This will be Cincinnati's tallest Skyscraper. Great American Insurance will occupy about two-thirds of the 800,000 square-foot office space. An 11-level garage will accommodate 1,700 parking spaces. Retail outlets will fill thousands of square feet on the buildings street level along with several restaurants and banks. The construction is expected to inject $715 million into the regional economy.
Slag cement was used because of its ability to reduce the heat-of-hydration. This project had a two month time frame to test and accept an appropriate concrete mix-design for a mass concrete foundation structure. Five different slag cement concrete mixes were evaluated.
The approved designed mix was 7,500 psi @ 91 days.
- 536 lbs/cuyd of a Type I portland cement and 289 lbs/cuyd of slag cement
- Actual tested strength: 5,900 psi @ 7-days, 8,300 psi @ 28-days, 8,800 psi @ 56-days and 12,000 psi @ 91-days
- Average ambient temperature was recorded at 28 degrees and the concrete at 53 degrees
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On January 18, 2009, the concrete suppliers provided the 6,000 cuyds; this was a continuous placement lasting 14 hours without any delays.
Slag Cement Consumption: Approximately 950 tons of an ASTM C989 slag cement was used in the project.
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