This specification covers slag cement for use as a cementitious material in concrete and mortar. The material described in this specification may be used for blending with portland cement to produce a cement meeting the requirements of AASHTO M 240M/M 240 or as a separate ingredient in concrete or mortar mixtures. The material may also be useful in a variety of special grouts and mortars and, when used with an appropriate activator, as the principal cementitious material in some applications.