Properties of Composite Modified with Limestone Powder for 3D Concrete Printing
The design of proper mixes for 3D concrete printing has been already a subject of many studies. Modification to mixes aim to obtain certain properties (extrudability, workability, flowability, open time or buildability) which allow for proper printing of the material. There are different types of reactive or non-reactive mineral additives that were already used to modify the mixes for 3D concrete printing. Studies have already shown the usefulness of fly ash, silica fume, metakaolin, limestone powder or quartz powder. The properties of the mix can also be changed with different chemical admixtures such as plasticizer, accelerators or retarders and viscosity modifying agents. Use of different admixtures can however significantly increase the cost of designed mixes. The study determined the influence of non-reactive limestone powder on the properties of the mix. The mixes were modified with 10% to 50% of additive, that replaced the fine aggregate. Rheological properties of the mixes were studied in this research. The stiffness and load-bearing capacity of mixes (t ≤ 45 min) were tested. Chosen mixes were printed out to experimentally verify the results. The study has shown that the limestone powder can successfully be used to improve the properties of printing mixes with simultaneous reduction of cement content. The results are promising regarding the sustainable development attitude in modern constructions.