This work presents experimental and theoretical studies on gamma-ray shielding capabilities of bauxite-containing refractory concretes containing new types of inorganic cements belonging to the CaO-AlO (as a reference), CaO-BaO-AlO-ZrO and CaO-AlO-FeO-ZrO systems. Firstly, the structure, microstructure, hydration behavior of cements, and thermal stability analysis of hydration products were investigated using X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM-EDS) and Thermogravimetry-Differential Scanning Calorimetry (TG-DSC) coupled with Evolved gas analysis-mass spectrometry (EGA-MS). When both FeO and BaO occur in the form of hydraulic phases as CaAlFeO and BaAlO, respectively, or are structurally incorporated into CaZrAlO, the iron and barium modify the nature of hydration products of the CaO-AlO-HO-type. Secondly, three types of concretes containing refractory bauxite aggregates were developed and tested in terms of microstructure, phase content, volumetric density, and weight loss. The maximum weight loss at 110 °C was associated mainly with the evaporation of the capillary water and the physically adsorbed water (gel water), whereas the chemically bound water (crystal water) occurring in hydrates was released at higher temperatures. Slight variations of the volumetric density of the concretes due to temperature were found. The CCS of the concretes fell within the standard values of ca. 50–100 MPa for shielding refractory concretes. Finally, the effect of temperature on the gamma radiation shielding capabilities of concretes was evaluated using the transmission method for gamma rays with energy in the range of about 81–1400 keV. The obtained values of the linear and mass attenuation coefficients showed improvement in the shielding properties as compared with ordinary concrete. Moreover, the obtained results show no significant effect of elevated temperature on the gamma radiation attenuation properties of the studied bauxite-based refractory concretes which suggests that they may be very useful as shielding materials in severe thermal working conditions.

中文翻译：

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温度对铝土矿基耐火混凝土伽马辐射屏蔽能力的影响


本工作对CaO-Al2O（作为参考）、CaO-BaO-Al2O-ZrO 和 CaO-Al2O-FeO 等新型无机水泥的含铝土矿耐火混凝土的伽马射线屏蔽能力进行了实验和理论研究。 -ZrO系统。首先，利用X射线衍射、扫描电子显微镜/能量色散X射线光谱仪（SEM-EDS）和热重-差示扫描量热法研究了水泥的结构、微观结构、水化行为以及水化产物的热稳定性分析。 TG-DSC）与逸出气体分析-质谱法（EGA-MS）联用。当 FeO 和 BaO 分别以 CaAlFeO 和 BaAlO 的水硬相形式存在时，或者在结构上并入 CaZrAlO 中时，铁和钡改变了 CaO-Al2O-H2O 型水合产物的性质。其次，开发了三种含有耐火铝土矿骨料的混凝土，并对其微观结构、相含量、体积密度和重量损失进行了测试。 110°C 时的最大失重主要与毛细管水和物理吸附水（凝胶水）的蒸发有关，而水合物中出现的化学结合水（结晶水）在较高温度下被释放。发现混凝土的体积密度因温度而略有变化。混凝土的 CCS 落在约标准值范围内。 50–100 MPa 用于屏蔽耐火混凝土。最后，采用能量在81~1400 keV范围内的伽马射线透射法评估了温度对混凝土伽马辐射屏蔽能力的影响。 获得的线性和质量衰减​​系数值表明，与普通混凝土相比，屏蔽性能有所改善。此外，所获得的结果表明，高温对所研究的铝土矿基耐火混凝土的伽马辐射衰减性能没有显着影响，这表明它们可能作为严酷热工作条件下的屏蔽材料非常有用。