EXPERIMENTAL INVESTIGATION OF THE INFLUENCE OF CHEMICAL ADMIXTURES ON THE BASIC PROPERTIES OF 3D PRINTED CONCRETE

This study analyzes the impact of chemical admixtures on the basic properties of 3D printed concrete. The investigation was carried out using two commercial chemical admixtures, the superplasticizer SikaViscoCrete®-5500 Iron and the hydration controller SikaTard®-930, both manufactured by Sika. The experimental program included the testing of concrete properties in fresh and hardened states, using four different mixtures (named A, B, C, and D), which were prepared by varying the dosages of the used admixtures. The open time and extrudability were determined in the fresh state for all mixtures, and the extrudability test was used as an indicator of the printability of the concrete mixture. For selected mixtures (A and D), the bulk density and compressive strength was tested at various ages on mold cast and 3D printed samples. Based on the obtained results, an analysis of the impact of chemical admixtures was performed, highlighting the main conclusions regarding the effects of admixtures on the basic properties of 3D printed concrete.