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以碱激发偏高岭土-矿渣作为胶凝材料、花岗岩为骨料制备地聚物混凝土,通过扫描电镜SEM-EDS及显微硬度分析研究地聚物与骨料的界面粘结区的微观结构、分布,以及液固比和骨料尺寸对地聚物-骨料界面的影响。研究结果表明,在地聚物与骨料的界面区域存在界面过渡区(ITZ),包含了以N-A-S-H凝胶为主的固相和收缩裂缝,化学组分与地聚物凝胶有较大不同。界面过渡区沿骨料周围不同位置表现出明显的分布不均匀特性,骨料下缘处的界面过渡区的微观结构和硬度都显著更差。随着液固比及骨料半径的增大,其分布的不均匀性增加:骨料下界面ITZ中的裂缝宽度增大,N-A-S-H凝胶厚度减小且强度降低;但配比及骨料尺寸对骨料上界面及侧界面的ITZ影响并不显著。骨料下界面ITZ应是偏高岭土-矿渣基地聚物混凝土的薄弱区域。
Using alkali-activated metakaolin-slag as cementitious material and granite as aggregate, the geopolymer concrete was prepared. The microstructure and distribution of interfacial adhesion zone between geopolymer and aggregate were studied by scanning electron microscopy (SEM-EDS) and microhardness analysis , And the effects of liquid-solid ratio and aggregate size on the geopolymer-aggregate interface. The results show that there is an interfacial transition zone (ITZ) in the interfacial region between geopolymer and aggregate, which contains NASH gel-based solid phase and shrinkage cracks. The chemical composition is quite different from geopolymer gels . The interfacial transition zone shows obvious uneven distribution along the periphery of the aggregate, and the microstructure and hardness of the interfacial transition zone at the lower edge of the aggregate are significantly worse. With the increase of liquid-solid ratio and aggregate radius, the heterogeneity of distribution increases: the width of fracture in ITZ increases, the thickness of NASH gel decreases and the strength decreases; however, the ratio and aggregate size The influence of ITZ on the interface and side interface of aggregate is not significant. The ITZ of aggregate interface should be a weak area of metakaolin-slag-based geopolymer concrete.