Development and Characteristic of 3D-Printable Mortar with Waste Glass Powder

Three-dimensional concrete printing (3DCP) is emerging as an innovative technology and shows promise to revolutionize conventional construction modes. However, the current 3D-printed concrete (3DPC) generally requires higher cement content than conventional concrete to ensure its rheology for printing. From the perspective of cleaner production and reduce carbon emissions, this study explored the feasibility of replacing parts of cement with waste glass powder (WGP, 0%, 20%, 40%, and 60% by mass) and compared the properties of the developed 3DPC, including fluidity (flowable spread), rheology, heat of hydration, buildability, compressive strength, anisotropy, and drying shrinkage. The results showed that less than 40% WGP replacement had limited influence on the initial fluidity and static yield stress, as well as drying shrinkage, of 3DPC. Although the WGP inclusion decreased the compressive strength, it slowed down the fluidity loss and static yield stress increase, which could extend the workable time of the mixture for printing and improve buildability. The 40% WGP replacement was found increase to the buildability of the printing mixture from 150 mm to 155 mm. The printing mixture prepared with 60% WGP reduced the dying shrinkage by 50%. An exponential decay function between the fluidity and static yield stress was established so that the simple fluidity test could be used as an indicator of printability. The findings in this study provided a solution to reduce the consumption of cement in 3DPC, which could contribute to a greener production in the construction industry.

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