Application of 3D printing in building projects can enhance construction efficiency and productivity. Rheological properties play a key role in defining the suitability of different cement-based mixes for digital construction. In this study, the rheological behavior of the MgO-SiO system involving metakaolin (MK) as the silica source was thoroughly investigated. Mixes with two different MgO/MK ratios (1 and 1.5) were prepared and evaluated for their hydration process, solid phase analysis, and dispersion stability of suspension particles by utilizing isothermal calorimetry, zeta potential, XRD, and TG-DTG analyses. Results revealed that the median differential viscosity (), dynamic yield stress (), and static yield stress () of M50-MK50 were considerably greater than those of M60-MK40. The increase of over time adhered to the linear structuration model within 60 min of hydration. The small amplitude oscillatory shear (SAOS) test findings indicated that M50-MK50 paste had a larger storage modulus. Although the printed structure of M50-MK50 closely approximated the intended dimensions of the design, notable instability was evident in the first and third layers from bottom to top. Microscopic analysis revealed that the formation of a modest number of hydration products in the early stage, the tendency of the system to agglomerate due to the smaller particle size of MK, and the irregular morphology of MK are significant variables influencing the rheological behavior of the MgO-MK mixes.

中文翻译：

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了解数字化建设背景下活性氧化镁-偏高岭土体系的流变行为

3D打印在建筑项目中的应用可以提高施工效率和生产力。流变特性在确定不同水泥基混合物对数字建筑的适用性方面发挥着关键作用。在本研究中，深入研究了以偏高岭土 (MK) 作为二氧化硅源的 MgO-SiO 体系的流变行为。制备了两种不同 MgO/MK 比例（1 和 1.5）的混合物，并利用等温量热法、zeta 电位、XRD 和 TG-DTG 分析评估了其水合过程、固相分析和悬浮颗粒的分散稳定性。结果表明，M50-MK50 的中值微分粘度 ()、动态屈服应力 () 和静态屈服应力 () 显着大于 M60-MK40。水合 60 分钟内随时间的增加遵循线性结构模型。小振幅振荡剪切（SAOS）测试结果表明M50-MK50糊剂具有较大的储能模量。尽管 M50-MK50 的印刷结构非常接近设计的预期尺寸，但从下到上的第一层和第三层明显不稳定。微观分析表明，早期阶段少量水化产物的形成、由于MK粒径较小而导致体系团聚的倾向以及MK的不规则形貌是影响MgO流变行为的重要变量-MK 混合。