PSI - Issue 73

Loran Nermend et al. / Procedia Structural Integrity 73 (2025) 130–137 Author name / Structural Integrity Procedia 00 (2025) 000–000

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Fig. 1. Particle size distribution of used materials. Reprinted from Sikora et al. (2025).

Three types of mixes were prepared: Control mixture as well as 2 mixes containing nanosized radiation-shielding admixtures (2.5 vol%). The BG250 mix included a combination of pristine Bi 2 O 3 and Gd 2 O 3 particles in a fixed 1:1 mass ratio. The particle mixture had a density of 7.94 g/cm 3 and a specific surface area (SSA) of 5.20 m 2 /g. The BGS250 mix used a similar composition of Bi 2 O 3 and Gd 2 O 3 (same mass ratio), but the particles were coated with a silica shell composed of tiny spherical particles. As a result of the silica coating, the admixture exhibited a lower density of 5.35 g/cm 3 and significantly higher SSA of 45.02 m 2 /g. The graphical presentation of the synthesis process along with the transmission electron microscope (TEM) images is presented in Figure 2. Details regarding the raw material properties, synthesis procedures, nanoparticle characteristics, and mixing protocols as well as the rationale behind selecting a 2.5 vol% replacement rate, can be found in the previous studies by Cendrowski et al. (2024) and Sikora et al. (2025).

Fig. 2. Schematic representation of the synthesis process and TEM micrograph of produced admixture (green arrows indicates presence of silica particles on the surface of Bi 2 O 3 /Gd 2 O 3 particles). Based on Cendrowski et al. (2024)

2.2. Mix design Mix composition of 3DPC is presented in Table 1. In all cases, the composition of the components remained constant. The variation in the content of the nanosized admixture is a result of differences in particle density, as the replacement was based on volume, 2.5 vol% of cement was replaced with nanoparticles. Mixtures were produced following the protocol: