built faster than the law can read

Problem statement

As of the 2024 International Building Code (IBC), there are zero provisions for 3D printed concrete (3DCP) construction. The IBC and IRC — the basis for state building codes across the United States — do not recognize additively constructed concrete as a construction method. The only pathway for permitting is IBC Section 104.11 (alternative materials/methods), which requires expensive case-by-case evaluation by local officials who typically have no expertise in 3DCP. Three separate organizations — ICC, ACI, and ASTM — are developing standards in parallel with limited coordination, and NIST has flagged the risk of inconsistent guidance.

Why this matters

3DCP promises 30-50% reductions in construction time, significant labor cost savings, and the ability to create complex geometries impossible with traditional formwork. In a housing crisis where construction labor shortages are acute, this technology could meaningfully expand housing supply. But every 3DCP project in the U.S. requires jurisdiction-specific alternative materials approval. Structural performance is currently limited to one-story, Risk Category I/II structures in Seismic Design Categories A and B only — excluding most of California, the Pacific Northwest, and the Southeast. The next IBC update cycle is 2027, and state adoption typically lags 2-5 years beyond that.

What’s been tried and why it hasn’t worked

ICC published the first draft of ICC 1150 in November 2024, but it remains in public comment and covers only 3D concrete walls. ASTM F42.07.07 is developing test methods for cementitious AM materials. ACI Committee 564 and ITG-12 are developing code requirements targeting incorporation into ACI 332 by 2026. NIST and U.S. Army ERDC co-hosted a 2025 workshop to coordinate these parallel efforts. However, the three standards tracks are structurally uncoordinated: ICC writes building codes, ACI writes concrete design standards, and ASTM writes test methods — and none reference each other's drafts. Existing ASTM C09 concrete test methods do not directly apply because 3DCP processes fundamentally alter how specimens are sampled, consolidated, and extracted. ICON (the leading U.S. 3DCP company) must obtain individual ICC-ES evaluation reports for each wall system variant, an expensive and slow process.

What would unlock progress

A validated, consensus-based set of mechanical property test methods specifically designed for 3DCP specimens (addressing anisotropy from layer-by-layer deposition), plus a prescriptive code pathway for at least simple residential structures. The test methods need to account for the fact that 3DCP creates directionally-dependent material properties — compressive strength parallel to layers differs from perpendicular — which traditional cylinder compression tests don't capture. An integration standard that bridges ICC, ACI, and ASTM work products would prevent years of rework.

Entry points for student teams

A team could extrude cementitious specimens in stacked layers — with a small gantry or robot-arm concrete printer where one exists, or a syringe- or caulk-gun-scale analogue on a moving bed where it does not, since what governs the anisotropy is layer orientation, interlayer cycle time, and cold-joint bond rather than print volume — then test compressive and flexural strength parallel and perpendicular to the layers against cast controls from the same batch. This would directly contribute data to the test method development ASTM F42.07.07 needs, and the bench-scale version needs only a mixer, moulds, and a university materials lab's testing frame. A complementary approach needs no lab at all: surveying local building officials and plan reviewers on how they would evaluate a 3DCP permit application today — what evidence they would ask for, which alternative-materials pathway they would route it through, what would make them refuse — generates data on the adoption bottleneck the code committees are currently working blind on. Relevant disciplines: civil/structural engineering, materials science, construction management, policy.