Evaluation of Anisotropy and Statistical Parameters of Compressive Strength for 3D Printed Concrete (2024-07)¶

The compressive strength data of 3D printed concrete (3DPC) in X (Print direction), Y (Adjacent stripes), and Z (Stacked stripes) were collected and analyzed to evaluate its anisotropic behavior and statistical parameters. Similar to conventional cast concrete, there is a linear relationship between the compressive strength of 3DPC and the binder-to-water ratio (B/W). For the normalized strength data, the average ratios of X/C, Y/C, and Z/C at 28 days are 0.87, 0.80, and 0.82 respectively, indicating a decrease in the compressive strength and anisotropy compared to cast concrete. Compared to the coefficient of variation (COV) of cast specimens mentioned in the specifications, there is an increase of 4.3–69 %. The weak interfaces and unique pore shapes in 3DPC interact to cause stress concentration and redistribution of internal stresses, resulting in decreased compressive strength, anisotropy, and variability. This investigation can provide material parameters for studying the structural performance of 3DPC components.