An investigation of rheological properties and sustainability of various 3D printing concrete mixtures with alternative binders and rheological modifiers

This study assessed the performance of eco-friendly 3D printable mixtures prepared with various wastes such as fly ash (FA), granulated blast furnace slag, and marble dust. Additionally, the study investigated the impact of a viscosity-modifying agent (VMA) and silica fume (SF) on the mixtures’ rheological and mechanical characteristics. The influence of different wastes and VMAs on the fresh and hardened properties of printable mixes was investigated. Besides, the extrudability and buildability properties of the mixtures were evaluated with a manual extrusion device. The sustainability assessment was conducted using embodied CO2 and embodied energy index, integrating both the mixtures’ environmental implications and engineering characteristics. Experimental outcomes indicated that the inclusion of SF led to enhancements in the fresh properties of the 3D printable mixes. The VMA mixes exhibited significantly higher static yield strength than mixes incorporating SF. Considering printability and sustainability, the FA-SF mixture was identified as the optimal one.