Behavior of 3D Printed Concrete Walls Exposed to High Temperatures

Fire accidents can occur in all types of buildings, even three-dimensional (3D) printed concrete structures. The 3D printed concrete exhibits increased susceptibility to interlayer delamination under high temperatures, a critical vulnerability that can undermine structural integrity. The behavior of 3D printed concrete walls under such conditions, however, has not yet been thoroughly investigated. Therefore, in this study, two patterns of large-scale wall specimens were constructed and exposed to temperatures of approximately 1,200°C for 4 h to monitor their behavior and determine the most effective pattern of a 3D printed wall in a fire scenario. All wall specimens remained standing without failure, collapse, or fire penetration through cracks after heating. The inner truss of the wall mitigated the temperature gradient to the unexposed surface, where temperature reached 100°C. Finite-element analysis results revealed that vertical and horizontal cracking occurred due to thermal tensile stress exceeding the tensile strength of material. However, horizontal cracking was primarily due to delamination between interlayers in certain areas of the unexposed surface. This partial detachment facilitated the vaporization of internal moisture and prevented spalling and explosion of the surface during heating.