Total Solar Reflectance (TSR) was done according to ASTM C 1549. Three readings were taken on each sample along a diagonal line of the face of the concrete block (5" x 5" x 1" thick). The non-glossy side was tested by BASF Construction Chemicals. (Test specimens no longer exist.)
The Emissometer measurements were performed in accordance with ASTM C 1371. Samples were tested at room temperature and took at least 10 minutes for the probe to come to an equilibrium reading because it actually heats up the sample by ten degrees or so.
The Solar Reflectance Index (SRI) is a mathematical calculation based on the TSR value and Emissometer value. The mathematics are outlined in ASTM E 1980. TSR readings averaged 67.8%; Emissometer readings ranged from .88 to .90. Therefore the SRI is 82.
The High-SRI precast mix design is a variant of one of High Concrete Group's seven standard precast mixes, and was checked for SRI due to its brightness. The white cement is from Lehigh White Cement, the slag is LaFarge Grade 120. The rule of thumb on set times is 3-1/2 to 4 hours on white cement, up to six hours with slag; exact test times were not measured.