Influence of Supplementary Cementitious Materials on Fresh Properties of 3D Printable Materials

The development of printers and materials for 3D Printing Construction during the last two decades has allowed the construction of increasingly complex projects. Some of them have broken construction speed records due to the simplification of the construction process, particularly in non-standard geometries. However, for performance and security reasons the materials used had considerable amounts of Portland cement (PC), a constituent that increases the cost and environmental impact of 3D Printable Materials (3DPM). Supplementary Cement Materials (SCM), such as fly ash, silica fume and metakaolin, have been considered a good solution to partially replace PC. This work aims to study the inclusion of limestone filler, fly ash and metakaolin as SCM in 3DPM. Firstly, a brief literature review was made to understand how these SCM can improve the materials' 3DP capacity, and which methods are used to evaluate them. Based on the literature review, a laboratory methodology is proposed to assess 3DP properties, where tests such as slump and flow table are suggested. The influence of each SCM is evaluated by performing all tests on mortars with different dosages of each SCM. Finally, a mechanical extruder is used to extrude the developed mortars, which allowed us to compare the results of slump and flow table tests with the quality of extruded samples.