Determination of Print Speed Based on the Fresh Mechanical Strength over Time of Additively Constructed Concrete by Unconfined Compression (2024-09)¶

Additive construction is a complex process that is influenced by different factors, such as printing parameters, design and construction, as well as materials properties. Since no formwork is used, a fundamental understanding of shape stability and print stability is required to ensure the successful completion of printed components. Additionally, utilizing additive construction in remote field applications increases the variables associated with printing and requires a quantifiable methodology for both laboratory and on-site to maintain quality control. This study focuses on the use of the unconfined compression test to characterize the buildability of the fresh additively constructed concrete with 9.5 mm aggregates. Mechanical properties, such as load and elastic modulus gain, were evaluated in addition to plate buckling theory to determine the print stability of the printing process based on the two primary failure mechanisms: plastic collapse and elastic buckling. This study identifies a method of determining failure parameters to identify the layer deposition limit and print speed to decrease failure during the printing process.