Abstract: A structural element made of a composite material includes a plurality of modular cells disposed within the composite material that have tensile elements that create axially directed tension anchoring elements attached to the tensile elements that create compression with anchoring elements of proximate modular cells. The modular cells may be disposed randomly or in a patterned manner within the composite material. A stackable structural cell facilitates more efficient creation of beams or columns and can include rebar for some of the tension elements that are axially arranged. Additionally, modular cells and/or supported capsules may be added to increase tension and/or decrease mass or weight of the beam or column. The structural cell can further include a boundary layer for containing the composite material prior to hardening.