## 2 Experiment Study  
### Materials Used  
Table 1 summarizes the materials used in this study. OPC, VG, and SF were used as binders with Type I VG, selected for its large specific surface area and potential to enhance compressive strength. SF, a conventional high-strength admixture, was included for comparison. Additionally, tap water was used for mixing, and a superplasticizer was added to ensure the workability of the fresh concrete. The fine and coarse aggregates were made from hard sandstone quarried in the same area, crushed, and adjusted for particle size. Aggregates used in high-strength concrete must possess sufficient strength. The crushing value of the coarse aggregate, which indicates its strength, was measured according to British Standard Methods (BS 812-110) and found to be of high quality at 9.1%. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt}} \hline \hline \multicolumn{1}{c}{**Material**} & \multicolumn{1}{c}{**Applicable Standards, Physical Properties**} \\ \multicolumn{1}{c}{**(Manufacturing Company, Location)**} \\ \hline Ordinary Portland cement & JIS R 5210: 2019, density: 3.16 g/cm\({}^{3}\), BET surface area: 0.326 m\({}^{2}\)/g \\  & (Tokuyama Corporation, Shunan, Japan) \\ \hline Fine volcanic glass powder & JIS A 6209: 2020, Type I, density: 2.37 g/cm\({}^{3}\), BET surface area: 9.5 m\({}^{2}\)/g \\  & (Principle Co., Ltd., Kagoshima, Japan) \\ \hline Silica fume & JIS A 6207: 2016, density: 2.26 g/cm\({}^{3}\), BET surface area: 16.5 m\({}^{2}\)/g \\  & (Egyptian Ferroalloys Co., Cairo, Egypt) \\ \hline Water & Tap water \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Properties of materials. Table 2 presents the chemical compositions of the binders, determined using X-ray fluorescence (ZSX Primus II, Rigaku Corporation, Akishima, Japan). Notably, VG has a lower silicon content, but a higher aluminum content compared to SF. Figure 3 presents the X-ray diffractometry (XRD) patterns of the binders. The OPC exhibited peaks corresponding to tricalcium silicate (3 CaO\(\cdot\)SiO\({}_{2}\), C\({}_{3}\)S), dicalcium silicate (2 CaO\(\cdot\)SiO\({}_{2}\), C\({}_{2}\)S), calcium aluminate (3 CaO\(\cdot\)Al\({}_{2}\)O\({}_{3}\), C\({}_{3}\)A), and tetrac calcium aluminoferrite (4 CaO\(\cdot\)Al\({}_{2}\)O\({}_{3}\)\(\cdot\)Fe\({}_{2}\)O\({}_{3}\), C\({}_{4}\)AF), which are key components of clinker. In contrast, both VG and SF were predominantly amorphous; however, VG contained crystalline phases such as quartz and albite. \begin{table}
\begin{tabular}{l l} \hline \multicolumn{1}{c}{**Material**} & \multicolumn{1}{c}{**Applicable Standards, Physical Properties**} \\ \multicolumn{1}{c}{**(Manufacturing Company, Location)**} \\ \hline Superplasticizer & JIS A 6204: 2011, Type I, Polycarboxylic acid-based, SF500U \\  & (Flowuric Co., Ltd., Toshima-ku, Japan) \\ \hline Fine aggregate & JIS A 5005: 2020, Crushed sand, density: 2.61 g/cm\({}^{3}\), Fineness modulus: 3.02 \\  & (Nanshu saiseki Co., Ltd., Hioki, Japan), \\ \hline Coarse aggregate & JIS A 5005: 2020, Crushed stone, density: 2.66 g/cm\({}^{3}\), Fineness modulus: 6.64, \\  & aggregate crushing value: 9.1\% (BS812-110) \\  & (Nanshu saiseki Co., Ltd., Hioki, Japan), \\ \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
Figure 2: Appearance and SEM images of binders. (**a**) Appearance of OPC; (**b**) appearance of VG; (**c**) appearance of SF; (**d**) SEM image of OPC; (**e**) SEM image of VG; (**f**) SEM image of SF. Figure 4 illustrates the particle size distributions of the binders. Particle sizes were measured using a laser diffraction/scattering particle size distribution analyzer (LMS-2000e, Seishin Enterprise Co., Ltd., Shibuya-ku, Japan). Ethanol (special grade) was used as the dispersion medium for OPC, ion-exchanged water for VG, and a 0.2% sodium hexametaphosphate solution for SF, with the latter also undergoing ultrasonic vibration treatment to enhance dispersion. The average particle size of VG was found to be 3.41 \(\upmu\)m, compared to 1.53 \(\upmu\)m for SF.