Sheet silicates, also known as phyllosilicates, include minerals like micas, clays, and chlorites, characterized by their layered structures. These minerals can influence the properties of cement and concrete due to their fine particle size and high surface area. In concrete, sheet silicates are primarily used as additives or fillers, where they can participate in pozzolanic reactions with calcium hydroxide to form additional calcium silicate hydrate (C-S-H), enhancing the strength and durability of the concrete. The unique layered structure of sheet silicates facilitates water retention and can impact the rheological properties of cement pastes, making them important in the formulation of specialty concretes.