I-P cement is a blended cement. Blended cements are used in all aspects of concrete construction in the same manner as portland cements (such as Type II/V or Type III). They can be used as the only cementitious material in concrete or in combination with other supplementary cementitious materials added at a concrete plant.
Blended hydraulic cements are produced by intimately and uniformly intergrinding or blending two or more cementitious materials. The primary materials used in Permanente I-P(25)(MS) cement are portland cement and 25 weight-percent of natural pozzolan (a naturally occurring siliceous material that reacts with cement during hydration, enhancing strength and durability). The (MS) designation indicates that the cement provides moderate resistance to sulfate attack as defined by the ASTM specification.