Development of EPS Light‐weight Concrete for 3D Printing (2025-05)¶

This study investigates the feasibility of 3D printing lightweight concrete (LWC) incorporating expanded polystyrene (EPS) beads, with a focus on optimizing mechanical properties and flowability for 3D concrete printing (3DCP). The research addresses the need for printable, structurally viable lightweight materials by developing and testing LWC mixtures modified with EPS beads, evaluated through ASTM standard tests for compressive strength, flexural strength, flowability, and printability. Hardened densities ranging from 2213 to 752 kg/m3 were achieved, and results showed that while EPS reduces flowability, the addition of superplasticizers allows for improved printability. Variations in EPS volume replacement revealed critical insights: replacements above 60% led to substantial declines in paste cohesion and flowability, with higher EPS volumes (60%–70%) causing a lumpy, rubbery texture and resulting in densities lower than water, making samples float. Mixtures with higher EPS volumes demonstrated more ductile behavior and steady energy absorption without sudden failure, though at the expense of compressive strength, which dropped to 4.2 MPa for 50% EPS—a significant reduction from 23.6 MPa in standard concrete. Although printable up to 50% EPS, these mixtures require further optimization for general structural applications, positioning EPS-based LWC as a promising material for specific 3DCP uses.