3D Printable Ca(OH)2-based geopolymer concrete with steel fiber reinforcement

IF 3.4 3区工程技术 Q2 CONSTRUCTION & BUILDING TECHNOLOGY

Materials and Structures Pub Date : 2025-02-20 DOI:10.1617/s11527-025-02600-5

Youssef Mortada, Ahmad Hammoud, Laith Masoud, Mateusz Wyrzykowski, Davide Sirtoli, Pietro Lura, Bilal Mansoor, Eyad Masad

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引用次数: 0

Abstract

This study investigates the impact of varying steel fiber (SF) content (0%, 0.8%, 1.0%, and 1.2% by volume) on the mechanical and durability properties of 3D-printed Ca(OH)₂-activated geopolymer concrete (GPC). The addition of 1.2% SF improved flexural strength by 69% at 7 days and 16% at 28 days, while tensile strength more than doubled to 3.75 MPa at 28 days. Although compressive strength remained unaffected at 43 MPa, SF enhanced interlayer bond strength by 20%, which is crucial for layer cohesion in 3D-printed structures. Additionally, the elastic modulus increased by 7%, contributing to improved stiffness. Durability assessments, including autogenous shrinkage and self-induced stress, indicated a slight reduction in shrinkage of SF-reinforced samples, with no significant effect on self-induced stress. Microstructural analysis using scanning electron microscopy (SEM) and X-ray micro-computed tomography (µCT) demonstrated the crack-bridging behavior of steel fibers, enhancing ductility and fracture resistance. There was a slight increase in porosity (5.34%) of SF-reinforced samples without negatively affecting their mechanical properties. Notably, SF improved early-age toughness and controlled crack propagation across printed layers, addressing a critical challenge in 3D-printed concrete. The novelty of this work lies in successfully reinforcing 3D-printed Ca(OH)₂-activated GPC with recycled steel fibers, enhancing mechanical properties, interlayer bonding, and durability without compromising printability. This study offers a sustainable reinforcement strategy for 3D printing in construction.

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带有钢纤维增强的可3D打印Ca(OH)2基地聚合物混凝土

本研究探讨了不同钢纤维（SF）含量（按体积计为0%、0.8%、1.0%和1.2%）对3d打印Ca(OH)2活化地聚合物混凝土（GPC）的机械性能和耐久性的影响。加入1.2% SF后，7天的抗弯强度提高了69%，28天的抗弯强度提高了16%，28天的抗拉强度增加了一倍多，达到3.75 MPa。虽然抗压强度在43 MPa时没有受到影响，但SF使层间结合强度提高了20%，这对3d打印结构中的层间凝聚力至关重要。此外，弹性模量增加了7%，有助于改善刚度。耐久性评估，包括自收缩和自诱导应力，表明sf增强样品的收缩略有减少，对自诱导应力没有显著影响。利用扫描电子显微镜（SEM）和x射线显微计算机断层扫描（µCT）进行的显微组织分析表明，钢纤维具有裂纹桥接行为，增强了延展性和抗断裂性。孔隙率略有增加（5.34%），但对力学性能没有负面影响。值得注意的是，SF提高了早期韧性，并控制了打印层之间的裂纹扩展，解决了3d打印混凝土的关键挑战。这项工作的新颖之处在于，它成功地用回收的钢纤维增强了3d打印的Ca(OH)2活化的GPC，增强了机械性能、层间粘合和耐用性，而不影响打印性。本研究为3D打印在建筑中的应用提供了一种可持续的加固策略。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Materials and Structures 工程技术-材料科学：综合

CiteScore

6.40

自引率

7.90%

发文量

222

审稿时长

5.9 months

期刊介绍： Materials and Structures, the flagship publication of the International Union of Laboratories and Experts in Construction Materials, Systems and Structures (RILEM), provides a unique international and interdisciplinary forum for new research findings on the performance of construction materials. A leader in cutting-edge research, the journal is dedicated to the publication of high quality papers examining the fundamental properties of building materials, their characterization and processing techniques, modeling, standardization of test methods, and the application of research results in building and civil engineering. Materials and Structures also publishes comprehensive reports prepared by the RILEM’s technical committees.