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Short answer
3D-printed concrete is a form of additive manufacturing in which a computer-controlled system extrudes cement-based mortar layer by layer to form building components or in-situ walls. It is not a single standard mix or product: results depend on print settings and material behaviour, and the governing standards and committees are still being developed.
Definition and scope
Buswell and co-authors, in their research roadmap in Cement and Concrete Research (October 2018, doi:10.1016/j.cemconres.2018.05.006), describe large-scale construction additive manufacturing as the computer-controlled placement of extruded cement-based mortar in layers. Applications they list include manufacturing components and printing walls in place on site. The topic sits inside civil engineering and, for building design questions, architecture. It is cementitious additive manufacturing, so it is a different field from metal additive manufacturing.
How it is used in practice: printability
Review literature on the subject frames printability as three linked properties: pumpability (the material can be moved to the nozzle), extrudability (it can be pushed out as a continuous filament) and buildability (the lower layers carry the weight of the layers above before they harden). Chang, Chen, Schlangen and Savija, in a 2023 review in Developments in the Built Environment on quantifying buildability, describe buildability in terms of the critical height at which a printed structure fails, with elastic buckling and plastic collapse of the lower layers as the failure modes.
An experimental study in Materials 2020, 13(21), 4919 (doi:10.3390/ma13214919, open access) shows which settings matter. It varied nozzle speed, interlayer interval time, the rotation speed (RPM) of the screw in the printing device, and the presence of lateral supports. Its reported findings:
- Buildability improved with a longer interlayer interval, tested up to 300 seconds.
- Printing was interrupted by tearing of the concrete filaments, which the authors related to excessive screw RPM.
- A lateral support with a wide contact surface improved resistance to buckling failure.
- Compressive, splitting tensile and flexural tensile strengths depended significantly on the bonding between printed layers.
- Metal laths, expected to raise tensile strength, reduced tensile performance because of weak bonding between the reinforcement and the concrete filaments.
These are results of one study with its own equipment and mix, not general rules.
Standards and committees: what is and is not covered
Two bodies define the governance picture. The table below compares them using only what each publishes about its own scope.
| Body | What it covers | What it states it does not cover or has not yet published |
|---|---|---|
| ISO/ASTM 52939:2023, Additive manufacturing for construction: Qualification principles: Structural and infrastructure elements (1st edition, December 2023, ISO/TC 261) | Quality assurance requirements for additive construction on building and construction projects; criteria for the process, quality-relevant characteristics, and the activities and sequences within an additive construction cell (site) and project | Design approvals; characterization and testing of material properties; environmental, health and safety for printer setup, material handling and robot operation; metals |
| ACI Committee 564, 3-D Printing with Cementitious Materials | Develops and reports information on 3-D printing (additive manufacturing) with inorganic cementitious materials; goals include two publications (broad impacts and challenges, and construction applications) and guidelines for evaluating materials and technology, coordinated with RILEM, ASTM, PCI, ISO and ASCE/SEI/EMI | The committee page lists no published committee documents as of 2026-11-08 |
ACI 564 works through five subcommittees: Emerging Technology Report, Structural Design and Testing, Material Testing and Formulation, Modeling and Performance Prediction, and Codes and Standard Review. The gap is informative. ISO/ASTM 52939 addresses process qualification, and explicitly leaves material property testing and design approval to other documents, while the ACI subcommittees on material testing and structural design show where that work is being organised.
Where it matters for labs
Because the qualification standard excludes material characterization, a laboratory or test report on printed concrete is where material evidence has to be stated. The checklist below is limited to the variables the sourced 2020 study identified as affecting results. A report that omits them cannot be compared with another report.
- Nozzle speed.
- Interlayer interval time.
- Screw RPM of the printing device.
- Whether lateral supports were used and their contact surface.
- Specimen orientation relative to the printed layers, since strengths in that study depended on interlayer bonding.
- Whether reinforcement such as metal laths was present, given its reported effect on bonding.
Common misunderstandings
- It is one standard material. No. The sources describe cement-based mortar extruded under adjustable machine settings, and results shifted with those settings.
- A published standard certifies the concrete. ISO/ASTM 52939:2023 is a qualification-principles standard that excludes material property characterization and testing.
- ACI has issued a guide. The ACI 564 committee page lists goals for publications but no published documents as of 2026-11-08.
- It is the same as 3D printing in metal. The ISO/ASTM scope excludes metals, and ACI 564 covers inorganic cementitious materials.
- Reinforcement always strengthens it. In the 2020 study metal laths reduced tensile performance because of weak bonding.
FAQ
What is 3D-printed concrete?
Cement-based mortar extruded layer by layer under computer control to make components or walls in place, a form of additive manufacturing for construction.
What does buildability mean?
The ability of freshly printed lower layers to support those above. Reviews quantify it as the critical height to failure.
Is there a standard for it?
ISO/ASTM 52939:2023 covers qualification principles for additive construction; it excludes material property testing and design approval. See also ASTM Compass and how to cite ASTM standards.
Sources
- ACI Committee 564 page, concrete.org (read 2026-11-08): 3-D Printing with Cementitious Materials.
- ISO/ASTM 52939:2023 catalogue record, ISO (read 2026-11-08): iso.org/standard/81177.html; scope only, full text not reviewed.
- Buswell, Leal de Silva, Jones, Dirrenberger (2018), Cement and Concrete Research, doi:10.1016/j.cemconres.2018.05.006.
- Materials 2020, 13(21), 4919, doi:10.3390/ma13214919 (Crossref record read 2026-11-08).
- Chang, Chen, Schlangen, Savija (2023), Developments in the Built Environment, review of buildability quantification.
