3D printing with geopolymer-stabilized excavated earth: Enhancement of printability and engineering performance through controlled retardation

Sahoo, P and Gupta, S (2025) 3D printing with geopolymer-stabilized excavated earth: Enhancement of printability and engineering performance through controlled retardation. In: Cement and Concrete Composites, 156 .

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Abstract

Excavated soil from widescale tunneling and excavation can be used in 3D-printed constructions. This research investigates the feasibility of 3D printing using geopolymer stabilized excavated soil (GP-E) containing 42 clay rich in kaolinite minerals. At dosages 0.50�1.5 wt, sucrose is added to control the hydration and time-dependent rheological properties, enabling adequate open printing time (OPT) for large-scale printing. Experimental findings show that 1 and 1.5 sucrose addition to GP-E offers OPT of 130 min and 170 min respectively compared to 32 min for GP-E. By enabling better dispersion, the addition of sucrose allows smooth extrusion with shape retention of 90 � 92 at a lower NaOH solution-to-binder ratio (0.68) than GP-E (0.75). Sucrose and clay (in the soil) act synergistically to reduce the time-dependent static yield stress but maintain it at an adequate level of 5�8 kPa required for stacking up the layers without collapse. Flow retention and thixotropy are maintained at 100 during the printing window, which balances extrusion and buildability. As a result, the sucrose-GP-E mix could be built up to a height of 1.05 m compared to 0.19 m for GP-E. 1 sucrose-added GP-E possesses 28 � 40 and 70 higher wet compressive strength and inter-layer bonding respectively compared to GP-E depending on the loading direction. These are linked to the refinement of capillary porosity and a 13�15 reduction in shrinkage. In summary, the findings present a potential route for controlling the printing time of geopolymer-stabilized earthen materials while reducing the embodied carbon and enhancing the mechanical performance. © 2024 Elsevier Ltd

Item Type:	Journal Article
Publication:	Cement and Concrete Composites
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to Elsevier Ltd
Keywords:	Carbon capture and utilization; Carbon sequestration; Compressive strength; Kaolinite; Tunneling (excavation); Yield stress, 3-D printing; 3D-printing; Carbon material; Engineering performance; Geopolymer; Low carbon; Low-carbon material; Natural clays; Retarder; Time dependent, Extrusion
Department/Centre:	Division of Mechanical Sciences > Centre for Sustainable Technologies (formerly ASTRA)
Date Deposited:	12 Dec 2024 16:47
Last Modified:	12 Dec 2024 16:47
URI:	http://eprints.iisc.ac.in/id/eprint/87004

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