## 3 Results and Discussion  
### Measured Temperature Profile and Temperature Gradient Frequency Distribution  
In railways, the maximum temperature gradient for track structure design references concrete pavement specifications. However, due to the large differences in dimension and environment boundary between the base plate and pavement, the data measured from pavement are not suitable for the base plate [33]. Many research investigations concentrate on thermo-mechanical analysis of the slab track but only in the operation stage and not in the construction stage [34; 35]. Since it is well known that a large part of temperature gradient in concrete plate is nonlinear and can cause large inner stress within the concrete, this section focuses on the statistical distribution of temperature gradient in field base plates cured with different regimes. As an example, Figure 7 presents the temperature distribution curves measured at the center of Plate I-a (covered by geotextile for 20 days) during a 24 h cycle from 12 November 2020 to 13 November 2020, 3 days after casting. It is clearly observed that the temperature measured at the top portion of the base plate had larger daily changes than the temperature at the bottom portion. Therefore, the temperature gradient along the depth in the top portion of the base plate was more pronounced than that in the bottom portion. In the current design specifications for CRTS track system, the nonlinear temperature gradient is ignored. Nevertheless, this section aims to assess the influences of environmental boundary conditions on the overall temperature gradient and not the characteristic of nonlinearity. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Component** & **Material** & **Elastic Modulus (GPa)** & **Poisson’s Ratio** \\ \hline Base plate & concrete & - & 0.2 \\ \hline Steel bar & Steel & 205 & 0.3 \\ \hline Girder & concrete & 50 & 0.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Mechanical parameters of the FE model components. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Component**} & **Material** & **Coefficient of Thermal Expansion** & **Specific Heat Capacity** & **Thermal Conductivity** & **Density** \\  & & **C**-1 & **(Q**-kg**\({}^{1.5}\)**C**-1)** & **(W**-m**\({}^{1.5}\)**C**-1)** & **(W**-m**\({}^{1.5}\)**C**-1)** & **(kg/m**\({}^{3}\)**)** \\ \hline Base plate & concrete & \(9.5\times 10^{-6}\) & 980 & 2.45 & 2500 \\ Steel bar & Steel & \(11.8\times 10^{-6}\) & 460 & 46.0 & 7800 \\ Girder & concrete & \(9.5\times 10^{-6}\) & 950 & 2.28 & 2500 \\ \hline Surface transfer & uncovered & covered by geotextile & covered by geotextile and quilt \\ coefficient & (W**-m**\({}^{2.5}\)**C**–1) & 16.8 & _7.0_ & & 1.55 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Material parameters of the FE model components for heat transfer analysis. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \(\mathbf{D_{0}}\) & \multirow{2}{*}{\(\mathbf{\alpha}\)} & \multirow{2}{*}{\(\mathbf{\beta}\)} & \multirow{2}{*}{\(\mathbf{H_{\mathrm{c}}}\)} & \multirow{2}{*}{\(\mathbf{\lambda\) (m\({}^{2}\)/d)}} & \multirow{2}{*}{\(\mathbf{p_{1}}\)} & \multirow{2}{*}{\(\mathbf{p_{2}}\)} \\ (\(\times\)**10\({}^{-5}\)/(m\({}^{2}\)/d))** & & & & & \\ \hline
8.36 & 0.049 & 1.5 & 0.925 & 0.020 & 0.0035 & 6.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Material parameters of base plate concrete for moisture diffusion analysis. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \(\mathbf{q_{1}}\) & \(\mathbf{q_{2}}\) & \(\mathbf{q_{3}}\) & \(\mathbf{q_{4}}\) & \(\mathbf{C}\) & \multirow{2}{*}{\(\mathbf{a}\)} & \(\mathbf{k_{1}}\) \\ (\(\times\)**10\({}^{-6}\)/MPa)** & (\(\times\)**10\({}^{-6}\)/MPa)** & (\(\times\)**10\({}^{-6}\)/MPa)** & (\(\times\)**10\({}^{-6}\)/MPa)** & (\(\times\)**10\({}^{-14}\)/MPa\({}^{2}\)/day) & **(MPa/K)** \\ \hline
32.5 & 41.6 & 21.5 & 24.3 & 7.2 & 1.0 & 2.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Material parameters of base plate concrete for the MPS theory-based creep model.