In 2005, The Citadel Military College began reconstructing the Law Barracks, a 1939 historical landmark. In 2004, industry experts had developed a mixture using self-consolidating concrete (SCC) to successfully restore the Padgett-Thomas Barracks. Moving on to the Law Barracks, The Citadel again chose SCC to alleviate difficult placement issues. The mixture uses Master Builders' Glenium high-range water-reducing admixture, Rheomac 358 viscosity modifying admixture, and Pozzolith water-reducing admixture. More than 3600 of the 6400-plus cubic yards of structural concrete will be SCC.
As part of this project, a research team is attempting to develop practical SCC field tests to guide contractors in how to construct formwork when using SCC. This effort is focusing on the effects of coarse aggregate to total aggregate ratio, the effect of supplementary cementitious materials (such as silica fume and fly ash), the paste content of the mix, and the water-cement ratio. Laboratory testing on fresh and rheological properties at different times began in May. Technicians measured slump flow diameter, flow time (T70 time—the time it takes the mix to spread to a diameter of 70 cm), and rheological characteristics of SCC. The team began field-testing on two mixes with different aggregate ratios on a 6-inch wall equipped with three sets of four pressure cells. Test results indicated distinct differences between the T70 times for the two mixtures. The team also made an effort to determine the rate of dissipation—the rate at which formwork pressure decreased—and surface finish. The formwork pressure testing continues through May 2006.