Design and Development of an Eco-Friendly 3D Concrete Extrusion Nozzle with In-Nozzle Admixture Dosing and Continuous Mixing

Velarde J.; Huaricapcha G.; Lara M.; Sulen C. · Proceedings - 2026 11th International Conference on Automation, Control and Robotics Engineering, CACRE 2026 (2026) · DOI: 10.1109/cacre70248.2026.11672941

Resumen

Extrusion-based 3D concrete printing (3DCP) has demonstrated significant potential for automated and material-efficient construction; however, achieving both high resolution and structural reliability remains a major challenge. Limitations such as inconsistent extrusion flow, uncontrolled setting kinetics, and filament deformation continue to restrict applications requiring precision and durability. To address these issues, this paper presents the conceptual design of an extrusion nozzle incorporating in-nozzle admixture injection and continuous mixing. The proposed system enables the introduction of a rapid-setting accelerator directly into the mortar stream near the outlet, where an internal mixing element promotes homogeneous blending immediately prior to deposition. This approach aims to enhance buildability and surface quality by controlling setting behavior at the point of extrusion, without compromising pumpability. In addition, the system is conceived to be compatible with eco-friendly cementitious mixtures, including formulations incorporating 10% eggshell ash as a partial replacement of Portland cement. This contributes to reduced environmental impact and aligns with sustainable development goals related to industry innovation and responsible consumption (SDG 9 and SDG 12). The study integrates CAD modeling, analytical formulations, and computational fluid dynamics (CFD) simulations to evaluate internal flow behavior and mixing performance. The proposed framework establishes a foundation for future experimental validation and the development of adaptive 3D concrete printing systems capable of producing high-quality and structurally reliable components using sustainable materials.

Instituciones: Universidad Peruana de Ciencias Aplicadas