What are the current capabilities and challenges of 3D-printed concrete construction?

3D-printed concrete (additive construction) capabilities include: layer-by-layer deposition without formwork, complex geometries, rapid construction, reduced labor, and customization. Challenges include: rheology requirements (extrudability, buildability, open time window), layer bond quality (interlayer strength 60-90% of cast), reinforcement integration (mesh, fibers, post-tensioning, or robotic insertion), surface finish (layer lines), code compliance (no specific standards yet), scale-up for large structures, and cost competitiveness. Current applications: walls, small buildings, and architectural elements.