A study on eco-friendly materials for 3D printing – focused on Korean Hwangto(Loess)

Of the 37% of carbon dioxide emissions generated by the construction industry, 5–7% comes from cement processing. In response to this problem, ways to utilize soil, a material with low energy consumption, are being explored as an eco-friendly option. In particular, eco-friendly design is being emphasized in the construction field through 3D printing technology. The research method proceeds in two stages. The first measures the changes in drying shrinkage, volume mass, compressive strength, and flexural strength over 7 days for a test specimen created by mixing coffee, charcoal, and rice bran with Hwangto. In the second step, slaked lime, a solidifying material, is mixed and tested under the same test specimen conditions as in the first. As a result of the experiment, the higher the mixing ratio of Hwangto, the greater the compressive strength and flexural strength. In particular, coffee exhibited the highest compressive strength at 1.50MPa, while charcoal demonstrated the highest flexural strength at 0.51MPa. However, when solidifying materials were mixed, the overall strength decreased, especially in the case of coffee (1.50MPa for the first time/0.87MPa for the second time), which showed a 42% decrease. Overall, charcoal was the most suitable mixing material and exhibited consistent and stable strength values in all experiments. Based on these experimental results, a 1/50 scale pavilion was produced through 3D printing. The stable shape and appropriate strength of the result were confirmed, making it suitable for educational or practical purposes. It suggests the possibility of use across industries.