## 2 Materials and Methods
### Experimental Methods  
#### 2.3.1 Mixing and Handling UHPC Mix  
The technology or mixing process significantly impacts the quality of UHPC and its solidified form [25]. Mixing UHPC is a complex process that can be divided into two parts. First is the distribution mixing, where low shear forces and velocities alter the state of the mixture particles. The second is dispersion mixing, where high shear velocities disperse the accumulation of mixture particles [28; 29]. Theoretically, these effects manifest in UHPC being highly flowable (self-compacting). Therefore, mixing parameters, such as particle shape and size, distribution, density variation, and surface smoothness, are paramount. For the powder particles in the mixture to change their state, sufficient kinetic energy for mixing must be provided, which is significantly higher than that required for regular concrete. Depending on the corresponding consistency and viscosity, power and electricity consumption increase significantly. Dispersion mixing needs to ensure that the voids between coarse particles and fibers are filled with finer particles and that the gaps between solid particles are filled with water. This process helps release water, break up aggregates, and achieve the dispersion and homogenization of fibers [30; 31; 32]. To achieve uniformity in the production of UHPC specimens, all mixtures were mixed according to a standardized process, as shown in Figure 1.  
After casting and leveling the surface, UHPC samples were cured under the same conditions. Initially, the samples were naturally cured in a moist environment. After an additional 24 h, they were further cured in a controlled environment with a temperature of 80 \({}^{\circ}\)C for 72 h. Then, the samples were cured in laboratory conditions until they reached the age of 5 days and, finally, until they reached the age of 28 days for testing [33]. The elevated temperature significantly speeds up the chemical reactions in the c  
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multirow{2}{*}{**Mix**} & **Cement** & \multirow{2}{*}{**SF (kg/m\({}^{3}\))**} & **RHA** & **Fine Sand** & **Coarse Sand** & **Steel Fiber** & **SP \({}^{2}\)** & \multirow{2}{*}{**w/b 1**} \\  & **(kg/m\({}^{3}\))** & **(kg/m\({}^{3}\))** & **(kg/m\({}^{3}\))** & **(kg/m\({}^{3}\))** & **(kg/m\({}^{3}\))** & **(kg/m\({}^{3}\))** & **(\%)** & **w/b 1** \\ \hline SF10 & 1035.0 & 115.0 & - & 205 & 818 & 155 & 2.4 & 0.165 \\At 80 \({}^{\circ}\)C, hydration occurs much faster, leading to rapid development of strength and other mechanical properties. High-temperature curing promotes the formation of a denser microstructure. The increased temperature facilitates the more complete and more efficient hydration of cement particles, reducing porosity and increasing the density of UHPC. A 5-day curing period is sufficient to ensure that the hydration process of the cement is thorough, providing the necessary strength and durability for UHPC. The combination of 5 days and high temperature helps UHPC to develop early strength, saving time compared to traditional curing methods. It also aids in the reaction between hydrated cement lime and active mineral additives to produce hydro-silicate minerals, enhancing bonding and density. Additionally, it boosts the reaction between the surface of silica powder particles and lime produced during cement hydration, increasing the bond between the CKD phase and fine silica particles. Furthermore, strengthening the structure reduces the shrinkage of UHPC, preventing structural cracks after curing. These effects collectively increase the density, bonding phases, strength, impermeability, and corrosion resistance of UHPC.