Farmington Hills, Mich., April 5, 2023 – The Slag Cement Association (SCA) is proud to announce the winners of its 2022 Slag Cement in Sustainable Concrete Awards program. The winning projects were unveiled and celebrated on April 5, 2023, during the spring ACI Concrete Convention in San Francisco, California.
“It is great to see such a diverse selection of concrete projects be nominated and gain recognition this year.” stated SCA Marketing Director Nick Brimley. “All of the winners have illustrated how important slag cement is in improving the strength and durability of concrete, while also lowering the embodied carbon associated with concrete construction.”
Eighteen construction projects from across the United States were chosen to showcase the broad applications of slag cement and its impact on creating more durable and sustainable concrete. These construction projects were awarded in six categories. The categories include: infrastructure, high performance, architectural, durability, innovative applications, and lower carbon concrete. Two research projects on slag cement use were also honored in this year’s program.
The 2022 Slag Cement in Sustainable Concrete Construction Award Winners:
Infrastructure
Argentine Main Pump Station, in Kansas City, Kansas
E7R15 – US 301/SR 45, SR 676A at Bloomingdale & I75 DB, in Tampa, Florida
LA 1 Port Allen Bridge Replacement, in Port Allen, Louisiana
High Performance
Hunts Point Interstate Access Improvement Project, in New York City, New York
Metropolitan Park Phase 7 and 8, in Arlington, Virginia
ONE 22 ONE, in Nashville, Tennessee
Architectural
Aston Martin Residences, in Miami, Florida
Boston University Center for Computing & Data Sciences, in Boston, Massachusetts
The Reed at Southbank, in Chicago, Illinois
Durability
Ford Homes Historic District – Pavement Restoration, in Dearborn, Michigan· PTC Southern Beltway Interchange SR0576 55C2-1, in Canonsburg, Pennsylvania
SOFIE Interior Alteration for PETtrace Cyclotron Bunker, in Haverhill, Massachusetts
Innovative Applications
Big Sandy Dam Reservoir Enlargement, in Farson, Wyoming
FDOT T7468 – US 41 / SR 45 / Broad St, in Brooksville, Florida
Meta Data Center, in DeKalb, Illinois
Lower Carbon Concrete
55H Street – Georgetown Graduate Student Hall, in Washington, DC
Salesforce Tower Chicago, in Chicago Illinois
Red Barn Wind Farm, in Montfort, Wisconsin
The 2022 Slag Cement in Sustainable Concrete Awards Research Award Winners:
Reuse of Mine Wastes (Mine Tailings and Mine Waste Rocks) to Produce Geopolymer Building Materials
Arash Nikvar-Hassani, University of Arizona
To achieve sustainable construction and respond to the ever-increasing demand for construction materials, it is an urgent need to use innovative technologies, like geopolymerization, to produce green and sustainable construction materials. Therefore, this project investigates the utilization of low-reactive copper mine tailings (MT) with slag (SG) as a supplemental cementitious material to
produce green bricks based on geopolymerization technology. To this end, the effects of several parameters including NaOH molarity, Na2SiO3/NaOH ratio, SG content, forming pressure, water-to-solid ratio, and curing temperature on the physical and mechanical performance of geopolymer brick specimens are investigated through unconfined compression and water absorption tests. In
addition, the environmental and durability aspects of the produced geopolymer brick have been studied through static leaching tests and exposing the bricks to wet-dry and freeze-thaw cycles, respectively.
The results show that with the incorporation of SG as a supplementary cementitious material, geopolymer bricks that satisfy the ASTM requirements can be produced. Leaching analysis shows that the contaminants in the MT are successfully stabilized within the geopolymer framework. Durability analysis showed that the bricks passed 50 freeze-thaw cycles successfully and the weight loss during wet-dry cycles is less than 8% which is much lower compared to conventional cementitious material.
Effect of pH Reduction on Desorption of Bound Chlorides in Cement Pastes Containing Ground Granulated Blast Furnace Slag Exposed to De-icing and Anti-icing Salts
Mohammad Teymouri, Colorado State University
Concrete structure exposed to coastal environments suffers from severe chloride corrosion because seawater contains a high concentration of chloride ions. Another source of chloride is chloride-bearing de-icing and anti-icing salts solutions [1]. Chloride ions can be physically absorbed and chemically combined with cement hydration products [2]. Chloride binding is considered to have a beneficial influence on durability owing to the reduction of free chloride concentration in the pore solution [3, 4], thus substantially reducing the chance of corrosion in reinforced concrete.
The inclusion of slag enhances the durability of concrete [4] in terms of carbonation, acid attack, and sulfate attack [5]. Chen et al. [3] pointed out an increase in chloride binding capacity after including 20% slag in mixture proportions when samples were exposed to NaCl solution. Geng et al. [5] reported that replacing 30% of cement with slag improved chloride binding capacity. Thomas et al. [6] exposed a binder containing 25% slag to NaCl solution and reported higher chloride binding capacity than cement specimens. The primary reason for higher chloride binding contents in slag-containing binders is high aluminum contents in its chemical composition compared to cement, resulting in the formation of higher content of Friedel’s salt, which is the primary form of chemically bound chlorides.
In terms of durability and lower risk of corrosion, slag-containing pastes are preferable due to their higher binding capacity and lower released bound chloride contents. Replacing OPC with 25% and 50% slag enhanced chloride binding in NaCl, CaCl2, and MgCl2 solutions. In addition, the findings suggest that increasing the slag replacement level increases the system’s resistance against chloride desorption in concrete structures exposed to low-pH environments.
More information on the winning construction and research projects can be found at www.slagcement.org/awards.
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