Cementitious materials for construction-scale 3D printing: Laboratory testing of fresh printing mixture

In this study, a framework for performance-based laboratory testing of cementitious mixtures for construction-scale 3D printing is developed, where workability of a fresh “printing mixture” is studied in terms of print quality, shape stability, and printability window. Print quality is described using measures of surface quality and dimensions of printed layers. Details of two proposed test methods for evaluation of shape stability, namely, “layer settlement” and “cylinder stability” are also provided. Experimental study of four different mixtures revealed that inclusion of silica fume and Nano-clay significantly enhance shape stability. The results of five conventional test methods, as well as four proposed tests are used to discuss the performance of mixtures.