The effect of using surface functionalized granite powder waste on fresh properties of 3D-printed cementitious composites

The production of low-emission additive manufactured cementitious composites using functionalized rock powders offers promising mechanical properties and significantly reduces cement consumption. The effect of powder functionalization on the rheological properties of the mixture remains unclear, so this study investigated how mechanical and chemical functionalization of granite powder waste affects the viscoelastic properties of a cementitious mixture for additive manufacturing. Compression tests were used to track stress-strain changes over time, while Vane and slug tests measured yield stress in mixes with 20 % and 40 % cement replaced by natural (NGP), sieved (SGP), and carbonated granite powder (CGP). The results showed that all three powders (NGP, SGP, and CGP) increased yield stress compared to the reference mix, with CGP having the smallest effect. The functionalization of granite powder may enable the creation of desirable viscoelastic mixtures using sustainable materials. We observed that functionalizing granite powder (SGP and CGP) accelerated changes in the mixture rheological properties, with yield stress increasing by up to 33 %, while NGP showed minimal impact, similar to the reference mix. Differences between the Vane and Slug test results were also identified and their limitations described. • Functionalization of the granite powder grain surface allows its effect on the rheology of the cement mix to be altered. • Carbonisation of granite powder allows for a reduced environmental impact of the composite. • The method of functionalization influences the change in mechanical properties of the composite in the early-age.