This paper presents comprehensive investigation on the microstructure and micromechanical properties of the hydration products in alkali-activated slag by adopting the coupled techniques of nanoindentation, optical microscopy, backscattering electron (BSE) imaging and energy dispersive X-ray spectroscopy (EDS), aiming to provide insight into the formation mechanism of the dark rim in AAS. It is found that the dark rim is primarily comprised of a mixture of Mg-Al layered double hydroxide (LDH) and C-A-S-H gel, and the existence of this LDH phase contributes to the relatively high hardness and elastic modulus of the dark rim. The dark rim is in-situ formed in the outer layer of GGBFS. The dissolution and diffusion of Ca and Si in the outer layer of GGBFS results in a lower average atomic number in the dark rim region, contributing to its relatively lower grey level. Based on the experimental results, the formation mechanism of the dark rim is discussed in this investigation.

本文采用纳米压痕，光学显微镜，背散射电子（BSE）成像和能量色散X射线光谱（EDS）技术，对碱活化矿渣中水合产物的微观结构和微机械性能进行了综合研究。提供有关AAS中深色边缘形成机理的见解。发现暗边缘主要由Mg-Al层状双氢氧化物（LDH）和CASH凝胶的混合物组成，并且该LDH相的存在有助于暗边缘的相对较高的硬度和弹性模量。黑色边框在GGBFS的外层中原位形成。钙和硅在GGBFS外层中的溶解和扩散导致暗边缘区域的平均原子序数降低，导致其相对较低的灰度级。根据实验结果，探讨了暗缘的形成机理。