Internal curing is a process in cementitious materials where internal reservoirs of water, typically supplied by saturated porous inclusions like lightweight aggregates, provide moisture for hydration from within the matrix. This method is a critical strategy to mitigate self-desiccation and autogenous shrinkage, significantly enhancing the material's early-age hydration, mechanical performance, and long-term durability, especially in low water-to-binder ratio systems.