3D Printing Concrete with Byproducts (2024-06)¶

The use of 3D printing concrete is a promising technique that may change the construction field and the way to build. One of the most important issues to get an optimal 3D printing concrete is the suitable mix design and the specific requirements in terms of extrudability, buildability and pumpability. The mixes for 3D printable concrete usually incorporate high binder content and a great volume of fine aggregates. The use of industrial byproducts in 3D printing technology is a promising option to move this field towards sustainability. In this regard, some authors have analysed the use of alternative raw materials with low environmental impact replacing aggregates and supplementary cementitious materials (SCMs). This study focuses on the analysis of using alternative aggregates replacing conventional ones and the substitution of cement by SCMs derived from industrial byproducts for 3D printing concrete. Based on the literature, the advantages and limitations of using these wastes have been determined in relation to rheological properties, hardened properties and durability of concrete. Finally, the implementation of nonconventional wastes as SCMs for 3D printing was also analysed. As a result, these studies have proved that the incorporation of alternative aggregates in 3D printing applications is possible if the replacement percentage is limited to the specific values previously analysed. Regarding the conventional SCMs, it has been found that their use provides numerous opportunities to control the printability of 3D concrete. Finally, the use of alternative wastes as SCMs and aggregates is still in its early stages, but promising studies are beginning to be conducted. However, a more in-depth study of their characteristics is still necessary as well as the exploration of further alternatives.