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    From printing to performance: a review on 3D concrete printing processes, materials, and life cycle assessment
    (Springer Nature, 2025) Mishra, S.K.; Snehal, K.; Das, B.B.; C, R.; Barbhuiya, S.
    A paradigm shift in the construction sector has been driven by 3D concrete printing (3DCP), offering automated alternatives to conventional building methods. 3DCP enhances precision, efficiency, and consistency through robotic control and advanced printhead systems while reducing material waste and enabling design flexibility. This review examines the working principles, printer classifications (gantry-based and robotic arm-based), and operational parameters, highlighting printing speed, interlayer gap time, and nozzle size and shape as critical parameters for buildability, interlayer bonding, and extrusion quality. Their influence is discussed in relation to fresh properties (flowability, pumpability, extrudability, shape retention, and buildability) and hardened properties (compressive, tensile, and flexural strength, interlayer bonding, and durability). Mix design strategies for optimizing rheology, printability, and sustainable material selection are critically reviewed. Key durability concerns such as shrinkage, cracking, and weather resistance are addressed. Reinforcement methods, including steel bars, fibers, and embedment techniques, are also discussed. A life cycle analysis reveals that 3DCP reduces carbon dioxide emissions by up to 89.2% and construction costs by 30–40% through formwork elimination. Environmental impacts (waste generation, carbon footprint, and energy use) are assessed using regional and global data, considering embodied energy, transportation, and maintenance costs. Challenges such as regulatory hurdles, high initial investment, and the absence of standardized guidelines are identified. This review covers developments from the past decade, offering valuable insights for researchers, industry professionals, and policymakers regarding the advancements, limitations, and future directions of 3DCP. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.
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    3D printing aspects of fly ash and GGBS admixed binary and ternary blended cementitious mortar
    (Taylor and Francis Ltd., 2025) Mishra, S.K.; Upadhyay, B.; Das, B.B.
    This study investigates the integration of Ground Granulated Blast Furnace Slag (GGBS) and fly ash to sustainably reduce the usage of Ordinary Portland Cement (OPC) in 3D printable mortar to enhance printability and engineering performance. Four mortar mixes were developed, and their printability parameters, such as flowability, extrudability, open time, yield stress, shape retention, and buildability, were assessed. Among mixes, O70G30 (70% OPC, 30% GGBS) showed the best printability, with an 18.3% and 54.3% higher shape retention factor than the control and O70F30 mixes, respectively, which can be attributed to improved particle packing and 5.5% higher yield stress. However, its open time was 22.2% lower than the control. This reduction can be attributed to the finer particle size and higher specific surface area of GGBS, which increased water demand and accelerated the loss of workability. In the hardened state, O70G30 exhibited 24% lower water absorption and 18.5% reduced permeable porosity than the control, indicating a denser microstructure. Printed specimens exhibited anisotropic strength, with the highest values observed on the YZ plane and the lowest on the ZX plane. Depending on the loading direction and mix composition, their compressive strength was 9.4–35.6% lower than that of mould-cast samples, while the flexural strength improved by 16.19% to 40.18%. Microstructural analysis revealed a denser matrix with a lower Ca/Si ratio and enhanced secondary hydration, evidenced by stronger C–S–H peaks in XRD, pronounced Si–O–Si/Al bands in FTIR, and 41.22% higher bound water (WH) with reduced portlandite (CH) in TGA compared to O70F30. These promising results can be attributed to GGBS’s role in enhancing hydration, refining the microstructure, and improving the performance of 3D printable mortar, offering a sustainable and effective pathway for digital construction. Also, the Life Cycle Impact Analysis (LCIA) revealed that the incorporation of supplementary cementitious materials (SCMs) significantly reduces environmental impacts compared to the control mix. © 2025 Informa UK Limited, trading as Taylor & Francis Group.