## 2 Material and Method  
The silica sand used in this study was sourced from the Tlemcen region in northwest Algeria, renowned for its high silica content and well-defined granulometry, with particle sizes ranging from 0 to 5 mm. Fourier Transform Infrared Spectroscopy (FTIR) was applied using a Shimadzu FTIR 8400 spectrometer (Stimadzu Corporation, Kyoto, Japan) to assess its functional groups (Figure 1). The FTIR spectrum of the sand reveals that the prevailing chemical bonds consist of Si-O (Table 2). Particle size analysis was performed using a Mastersizer 2000 laser analyzer (Malvern Instruments, Malvern, UK) and the scanning electron microscope \"SEM\" Philips/FEI XL 30S FEG Chatsworth, CA, USA. The morphology of silica sand grains showcases angular shapes (Figure 2). Figure 3 shows an almost homogeneous size distribution of silica sand. \begin{table}
\begin{tabular}{c c} \hline \hline
**Frequency (cm\({}^{-1}\))** & **Vibration Kind** \\ \hline
458.68 & Si-O-Si \\
684.36 & Si-O vibration \\
767.89 & Si-O \\ \hline
1051.53 & Stretching vibrations Si-O-Si \\
1689; 1800; 3700 & Stretching H-OH \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The main bands of IR. Figure 1: Absorption spectrum of silica sand. The chemical composition of the materials was determined using X-ray fluorescence spectroscopy (Table 3). The epoxy resin selected for this study was a two-component, high-performance adhesive comprising a resin (part A) and a hardener (part B) mixed in a 4:1 ratio. Table 4 lists its properties. The properties of the resin presented in Table 4 are obtained from the technical data sheet ([[https://dza.sika.com/](https://dza.sika.com/)]([https://dza.sika.com/](https://dza.sika.com/)) accessed on 8 June 2024). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Density** & **Tensile Strength (MPa)** & **Young’s** & **Elongation** & **Glass Transition** \\
**(kg/L)** & **Tensile Strength (MPa)** & **Modulus (MPa)** & **at Break (\%)** & **Temperature (°C)** \\ \hline
1.3 & 30 & 4500 & 9 & 73.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Properties of the epoxy resin. Figure 3: Particle size distribution of silica sand. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Compound** & **SiO2** & **Al2O3** & **Fe2O3** & **CaO** & **MgO** & **K2O** & **Na2O** & **SO3** & **L.O.I. (\%)** \\ \hline (\%) & 98.91 & - & 0.5 & 0.52 & - & - & - & - & 0.02 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Chemical properties of the used crushed sand. Figure 2: Particle shape of silica sand grains. The composite synthesis involves a sequential blending process to ensure optimal filler incorporation. Table 5 lists the percentage of silica filler added to the composite, ranging from 0% to 15% by volume. These proportions are based on the total volume of the epoxy resin system (A + B), allowing for a detailed analysis of their impact on the composite properties. The density of the composite materials was determined using the hydrostatic weighing method according to the NF T 51-561 standard [32]. Density measurements were obtained by averaging the results from three samples, each subjected to double weighing at 22 \({}^{\circ}\)C Equation (1):  
\[\rho=\frac{\rho_{e}\times m_{r}}{m_{r}-\left(m_{f}-m_{p}\right)} \tag{1}\]  
where \(\rho\) and \(\rho_{e}\) are the densities of the sample and the immersion liquid (water), respectively, and \(m_{r}\), \(m_{f}\), and \(m_{p}\) are the sample's mass in air, the mass of the test tube with the sample holder, and the mass of the test tube holder in water, respectively. Unfilled (Mixture 1, without silica sand) and filled resin composite samples (Mixtures 2, 3, and 4, with silica sand) were prepared to investigate their mechanical properties. Tensile tests according to the ISO 527-2 standard [33] returned the elastic modulus, ultimate tensile strength, and elongation at break. Silicone holds ensured high-quality specimens with minimal defects (Figure 4).