Particle bed 3D printing by selective cement activation - Applications, material and process technology

The present work addresses particle bed binding by selective cement activation as an additive manufacturing process for cement-based materials in construction industry. Its focus is the effect of material and process on the microstructure and macroscopic properties of the hardened material. As macroscopic properties, strength and dimensional accuracy are characterized. The structure of the printed material is investigated on the micro scale by quantifying porosity and homogeneity of the layers. It is shown that material and process parameters such as the w/c-ratio, particle size distribution of the aggregates, addition of methylcellulose as well as the method of water application (spraying or jetting) have a significant effect on the properties of the additively manufactured specimens. Furthermore, the results clearly demonstrate the importance of a thorough analysis of the underlying mechanisms at the micro level for a comprehensive understanding of the material and process-related influences.