Abstract Current demand for highly sustainable concrete, e.g. alkali-activated fly ash-slag (AAFS) concrete, urges understanding the links between microstructure and micromechanical properties of this binder. This paper presents a systematic investigation into the microstructure and micromechanical properties of AAFS paste from nano-scale to micro-scale. Nanoindentation was used to evaluate the micromechanical properties, while the microstructure was characterised using 29Si nuclear magnetic resonance, Fourier transform infrared spectroscopy, backscattered electron microscopy, and mercury intrusion porosimetry. The results indicate that N-A-S-H gels have a relatively low elastic modulus due to their high level of structural disorder and gel porosity, while the C-A-S-H gels and N-C-A-S-H gels with a low level of structural disorder and gel porosity have a relatively high elastic modulus. The elasticity of reaction products and their relative volumetric proportions mainly determine the macroscopic elasticity of AAFS paste, while the porosity and pore size distribution primarily condition its macroscopic strength.

中文翻译：

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碱活化粉煤灰渣浆的多尺度微观力学分析

摘要 当前对高度可持续混凝土的需求，例如碱活化粉煤灰渣 (AAFS) 混凝土，迫切需要了解这种粘合剂的微观结构和微观机械性能之间的联系。本文从纳米级到微米级对 AAFS 浆料的微观结构和微机械性能进行了系统研究。纳米压痕用于评估微机械性能，而微观结构则使用 29Si 核磁共振、傅里叶变换红外光谱、背散射电子显微镜和压汞孔隙率测定法进行表征。结果表明 NASH 凝胶由于其高度的结构无序和凝胶孔隙率而具有相对较低的弹性模量，而结构无序和凝胶孔隙率较低的 CASH 凝胶和 NCASH 凝胶具有相对较高的弹性模量。反应产物的弹性及其相对体积比例主要决定了AAFS糊剂的宏观弹性，而孔隙率和孔径分布主要决定了其宏观强度。