Use of magnesium-silicate-hydrate (M-S-H) cement mixes in 3D printing applications

This study focused on the development of 3D printed building components incorporating MgO–SiO₂ binders. The effects of parameters such as MgO/SiO₂ and water/binder ratios and superplasticizer dosage were evaluated to produce 3D printable MgO–SiO₂ binders. The assessment of rheological and mechanical properties, which led to an optimum mix that satisfied the printability criteria, was supported by microstructural characterization. The best-performing mix in terms of printability and mechanical performance was characterized via x-ray diffraction (XRD), thermogravimetric analysis/derivative thermogravimetry (TG/DTG) and field emission scanning electron microscopy (FESEM) with energy dispersive spectroscopy (EDS). The selected mix exhibited thixotropic behaviour with an ability to recover ~80% of its original viscosity within 60 s of extrusion and a shape retention factor of ~1. The extrudability, shape retention and buildability aspects were successfully demonstrated by printing a 5-layered 3D structure without any deformations. The final product contained brucite and M-S-H as hydration products, which were the main contributor to mechanical performance and microstructural densification.