The improvement in the physico-mechanical properties of lime–silica fume (SF) pastes through the incorporation of nano-metakaolin (NMK) was investigated. Lime–SF paste (1 : 1 by weight) was prepared as a reference binder. To examine the influence of NMK on strength development, SF was replaced with 2–10 wt% NMK. The compressive strength, capillary water absorption and pore structure of the designed mixes were determined after 3, 7 and 28 d of curing. X-ray diffraction analysis and differential scanning calorimetry were used to study the phase composition and scanning electron microscopy (SEM) was used for microstructural investigations. The lime–SF binder modified with 6% NMK exhibited the best mechanical performance. Pore structure analysis confirmed that NMK provided significant refinement in the pore structure of the blended pastes and SEM micrographs revealed noticeable microstructural improvements. The capillary water absorption coefficient decreased considerably with an increase in NMK content up to 6% compared with the reference mixture. Use of the developed lime–SF–NMK paste is recommended as a promising innovative binder for specific cement applications such as plastering and renovation of buildings.

中文翻译：

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纳米偏高岭土改性的石灰硅粉浆料的物理力学性能

研究了通过掺入纳米偏高岭土（NMK）改善了石灰硅粉（SF）浆料的物理机械性能。制备石灰-SF浆料（重量比为1：1）作为参考粘合剂。为了检查NMK对强度发展的影响，用2-10 wt％的NMK代替了SF。在固化3、7和28天后确定设计混合物的抗压强度，毛细管吸水率和孔结构。X射线衍射分析和差示扫描量热法用于研究相组成，扫描电子显微镜（SEM）用于显微结构研究。用6％NMK改性的石灰-SF粘合剂表现出最佳的机械性能。孔结构分析证实，NMK在共混浆料的孔结构中提供了显着的细化，而SEM显微照片显示出明显的微观结构改善。与参考混合物相比，随着NMK含量的增加，毛细管吸水系数显着下降，最高可达6％。对于特定的水泥应用，例如建筑物的抹灰和翻新，建议将开发的石灰-SF-NMK糊剂用作有前途的创新粘合剂。