A method of manufacturing a concrete filled structure comprises coupling a plurality of wall segments together to form a wall structure; disposing a first plurality of rebar within the wall structure; and filling a cavity of the wall structure with concrete to form the concrete filled structure.

Systems and methods for providing an insulated, in-ground pool are disclosed. In some cases, the pool includes one or more basin floors or one or more basin walls. In some implementations, at least one of the basin floor and one or more basin walls include one or more layers of concrete, such as a first outer layer of concrete and a second outer layer of concrete. In some implementations, the pool includes an inner insulating core. In some cases, the inner insulating core is positioned generally between the first outer layer of concrete and the second outer layer of concrete such that the first outer layer of concrete, second outer layer of concrete, and inner insulating core form a unitary whole.