The influence of low-grade metakaolin (MK) on the mechanical and microstructural properties of cement paste was studied through compressive strength test and microstructural analyses, including thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). The results indicated that cement paste incorporating MK with around 40 wt.% kaolinite content in raw clays achieved comparable 28-day strength to that of the reference even at 40 wt.% replacement level. Microstructural studies showed a considerable amount of portlandite consumption after 3 d and a refinement of pore structure in backscattered micrographs. The Al/Ca ratio of calcium-aluminosilicate-hydrate (C-A-S-H) increased upon the increased replacement levels, while Ca/Si decreased due to the introduction of MK, but it did not further reduce with the increased MK content. The binding energy of Si 2p, Al 2p and Ca 2p spectra increased due to the incorporation of MK.

通过抗压强度试验和微观结构分析，包括热重分析（TGA），X射线衍射（XRD），扫描电子显微镜-能量色散，研究了低级偏高岭土（MK）对水泥浆力学和微观结构性能的影响。光谱（SEM-EDS）和X射线光电子能谱（XPS）。结果表明，即使在40％（重量）的置换水平下，在生粘土中掺入高岭石含量约为40％（重量）的MK的水泥浆，其28天强度也可达到参考值。显微组织研究表明，3 d后大量的硅酸盐消耗，并且在反向散射显微照片中细化了孔结构。铝硅酸钙水合物（CASH）的Al / Ca比随着置换量的增加而增加，Ca / Si由于引入了MK而降低，但并没有随着MK含量的增加而进一步降低。Si 2p，Al 2p和Ca 2p光谱的结合能由于掺入MK而增加。