Can Rocks and String Replace Concrete?

Have researchers found an alternative to concrete? Gramazio Kohler Research (GKR) has created a process using a 3D printing extruder, rocks, string and a smart design that it thinks is a step towards a concrete alternative. The process jams rocks together with algorithmically placed string.

The technique is similar to powder-based printing but uses a string as the binder between layers.

But GKR claims this process can one-up concrete because the structures can be disassembled and reassembled without any material losses.

(more on the testing of a "reversible concrete" process...)