EPS blocks are typically stacked as exterior walls. Rebar is placed in the cores vertically and horizontally. The cores are poured full of concrete from the top. Specify that the foam is protected from insects. Insects will not eat the foam but will nest in it.
Borate treatment is preferable.
Urethane block wall-form products are also available. Fiber-cement wall forms. Approximately R-12 ratings in 9 inch block. Hollow cores are filled with steel reinforced concrete. Foam Plastics 15 Thurber Blvd.