The Davis Wade Stadium (DWS) expansion and renovation project was announced in the spring of 2012. It included expansion of the stadium north end zone, along with a new concession concourse below west side seating. The end zone expansion added 6255 seats, increasing total seating capacity to 61,337 and making DWS the largest football stadium in Mississippi. The project was by far the most extensive upgrade investment made in the stadium’s 100 year history.
Mississippi State University (MSU) is home to the state’s largest College of Engineering as well as the state’s only Construction and Materials Research Center (CMRC), a partnership of the university with agencies and materials industries that are focused on research, development and education. As such, construction leadership and innovation are important elements in campus infrastructure projects, especially for highly visible facilities such as DWS.
The university and project designers were from the beginning committed to incorporating exemplary levels of sustainability in DWS construction. Concrete being a significant portion of the project, sustainable materials and mix designs were critical. Since much of the concrete was to be on-grade and structural flatwork, constructability concerns soon emerged over highly sustainable concrete mix designs. These typically use higher levels of cement replacement with supplementary cementitious materials (SCMs), known to delay setting and strength gain, which can impact finishing and cracking potential. To help explore these challenges and develop sustainable mixtures with optimum performance, MMC Materials and the CMRC began a collaborative effort of testing, evaluation, and coordination with the entire project team.
DWS project timing coincided with the initiation of a CMRC effort to investigate performance synergies of portland limestone cement (PLC) with SCMs in concrete. Considering the sustainability focus, the use of PLC in the project became a key objective, and was the perfect opportunity for field evaluation of the laboratory-proven PLC benefits relating to performance and sustainability. The developed flatwork mix design called for 50% total cement replacement with two SCMs (30% slag cement and 20% Class C fly ash). Since a new silo for PLC at the MMC plant was not operational until the project was well underway, concrete of this mix design was initially made with Type I/II ordinary portland cement (OPC), then later on with PLC, a fortunate coincidence that served research interests well, providing high-quality, comparative data.
The use of PLC in the sustainable concrete mix design was successful from every vantage point. Comparative field-sampled concrete data clearly showed strength benefits of PLC (as compared with OPC) at all ages (consistent with laboratory data), including increases of approximately 400, 800, and 1100 psi at 1, 3, and 7 days on average, respectively. There were also notable improvements in setting. These results translated to early concrete performance much like that of “traditional” flatwork mix designs not designed for sustainability. Project managers began to prefer and request the PLC mix in place of OPC mixes whenever possible. The project was completed without significant issues, and the stadium has seen record attendance for fall 2014 football games.