Assessment of Materials, Design Parameters and Some Properties of 3D Printing Concrete Mixtures (2021-12)¶

It was understood that 3D printing concrete mixtures (3DPC) have special requirements in terms of rheological properties compared to conventional concrete. It was found that there are no acceptance criteria, standards or guidelines for 3DPC and existing standards do not provide guidance on the mix design. It was observed that the development of mix design is necessary for the wider application of 3DPC. In this article, the effects of materials used in 3DPC mixtures on the printability performance of mixtures, especially rheological properties, were investigated by examining the studies in the literature. It was observed that use of sulfoaluminate-cement, which has advantages of rapid-setting, high strength and low-shrinkage, positively affects the performance of 3DPC. It was determined that use of supplementary- cementitious-materials improves rheological properties, while the addition of nano-clay and viscosity modifying agents increases the structural build-up. In addition, it was stated that the use of geopolymer, recycled aggregates and waste materials in the mix design of 3DPC mixtures can contribute to the improvement of the sustainability of 3DPC and the circular economy. It is necessary to control dimensional-stability parameters that occur due to the high dosage of binder content of 3DPC. It was stated that the type and dosage of fibers used were effective parameters in controlling this negativity.