Assay methods for hydratable cementitious compositions

A novel methodology for rapid, cost-efficient discovery, identification, or improvement of additives and/or admixtures for hydratable cementitious compositions. Multiple formulations comprising hydratable cementitious compositions are deposited into a plurality of receptacles. A first assay output is obtained, such as through x-ray diffraction, which is then correlated to provide a second assay output value corresponding to physical or chemical properties of the cementitious compositions.