ADVANCEMENTS IN ADDITIVELY MANUFACTURED SAFETY MATERIALS: ENERGY-EFFICIENT 3D PRINTING SOLUTIONS FOR CRITICAL INFRASTRUCTURE

3D concrete printing technology offers an ideal solution for resilient infrastructure development in critical and emergency situations, but accessing required materials and energy can be challenging. This study focuses on an integrated renewable energy system with hydrogen storage to support a mobile and autonomous 3D printing system. The system is designed to meet off-grid energy needs, including material synthesis. Two local materials were analyzed: Construction and Demolition Waste (CDW)-based geopolymer concrete and directly printable local materials. Due to the energy-intensive process required for producing geopolymers, direct printing with local materials is more favorable. Under steady-state conditions, the 5.36 kW system can print 2.86 m³ of local material or 0.22 m³ of geopolymer concrete in 24 hours. The feasibility, production capacity, and overall performance of the system were analyzed under varying solar irradiance conditions. The environmental impact analysis identified CDW-based geopolymer materials as a hotspot, mainly due to the alkaline solution and energy required for mechanical processing. Using local materials for direct printing significantly reduced energy consumption and eliminated the need for an alkaline solution, reducing environmental impact by over 95%. The study demonstrates the potential energy and environmental benefits of using local materials, suggesting further exploration is warranted.