Printing hardware, not the concrete itself, limits how light a bridge can be, as well as energy/ material consumption during construction

https://techxplore.com/news/2026-07-3d-bridge-greener.html

"topology optimization algorithms produce geometries impossible for commercial concrete nozzles to fabricate without days of manual redesign... overcome analyzing hardware constraints (bead thickness, minimum turning radii, continuous toolpath) generating printable designs in minutes on laptop... up to 76% less material consumption narrowing printed bead width from 4 to 1 cm... fabricated 2.3-m-long compression-only concrete bridge that supports >2k lbs with virtually no mechanical bending"