In this paper, various additives used for electromagnetic (EM) waves absorbing applications were investigated as fillers in cementitious mortars. The following additives were considered: graphite in the form of micro powder and flakes, carbon black, carbonyl iron, ferrite, and electromagnetic energy absorbing filler. Also, fly ash aggregate was considered as the replacement for the quartz sand. The main focus was placed on the microstructure changes caused by adding a selected additive to the mortar. For this purpose, X-ray micro-computed tomography, scanning electron microscopy (SEM), and nanoindentation techniques were utilized. The primary analysis concerned the calcium-to-silicon ratio for cement matrix mainly composed of calcium silicate hydrates (C–S–H). Also, the differences in the pores’ morphology were compared between samples. Finally, the microstructural properties were referred to the EM absorption performance and compressive strength obtained at the macroscale.

在本文中，研究了用于电磁 (EM) 波吸收应用的各种添加剂作为水泥砂浆中的填料。考虑了以下添加剂：微粉和薄片形式的石墨、炭黑、羰基铁、铁氧体和电磁能吸收填料。此外，粉煤灰骨料被认为是石英砂的替代品。主要关注由向砂浆中添加选定的添加剂引起的微观结构变化。为此，使用了 X 射线微计算机断层扫描、扫描电子显微镜 (SEM) 和纳米压痕技术。初步分析涉及主要由水合硅酸钙组成的水泥基体的钙硅比（C-S-H）。此外，还比较了样品之间孔隙形态的差异。最后，微观结构特性被称为在宏观尺度上获得的电磁吸收性能和抗压强度