# Study on Temperature Correction of Asphalt Pavement Deflection Based on the Deflection Change Rate
## 5 Deflection Temperature Modelling
### Validation  
To validate the applicability and repeatability of the temperature correction model, measured deflection data from one other road section was used for comparative analysis. This pavement was made of 150 mm asphalt concrete (AC) and 450 mm fly ash with a three slag base. Platinum thermistor sensors were also embedded in the AC layer to  
Figure 11: Deflection change ratio at each radial distance to the deflection change rate at 20 cm: (**a**) 20 cm; (**b**) 30 cm; (**c**) 45 cm; (**d**) 60 cm; (**e**) 90 cm. collect the temperature data, as previously mentioned in the FWD test sections. Deflection measurement points are arranged in each lane at intervals of 30 m. The detailed deflection and temperature data are summarized in Table 6.  
The backcalculated layer moduli based on the deflection are shown in Table 7. \(E_{\text{a}}\) and \(E_{\text{s}}\) are the backcalculated surface layer and subgrade moduli based on the uncorrected deflections, and \(E_{\text{aT}}\) and \(E_{\text{sT}}\) are the surface layer and subgrade moduli based on the corrected deflections using Equation (9). The definition of backcalculation accuracy is the proportion of the backcalculation moduli whose deviations are within an acceptable range. For the asphalt layer modulus, which has a variability of 15% in general, is considered acceptable when the surface layer backcalculation modulus is in the conventional deviation range of 85% to 115% [27]. Based on this, the percentage of \(E_{\text{aT}}\) within the deviation range is 92.9%, while the percentage of \(E_{\text{a}}\) is 78.5%. The subgrade modulus is considered acceptable when it is within the deviation range of 90-110%. Similarly, the percentage of \(E_{\text{sT}}\) within the deviation range was 92.9% while the percentage of \(E_{\text{s}}\) was 85.7%. The base modulus in this section has a high variability, and therefore no comparison is included. However, it can still be concluded from the comparison results of the surface \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**ID**} & \multicolumn{8}{c}{**Deflection/mm**} & \multirow{2}{*}{**150**} & \multirow{2}{*}{**180**} & \multirow{2}{*}{**17/C**} \\  & & & & & & & & & \\
1 & 0.0728 & 0.0568 & 0.0478 & 0.0451 & 0.0421 & 0.0340 & 0.0240 & 0.0231 & 0.0209 & 26.2 \\
2 & 0.0977 & 0.0813 & 0.0704 & 0.0656 & 0.0583 & 0.0428 & 0.0312 & 0.0290 & 0.0275 & 26.8 \\
3 & 0.0679 & 0.0521 & 0.0439 & 0.0424 & 0.0405 & 0.0331 & 0.0255 & 0.0239 & 0.0204 & 27.3 \\
4 & 0.0720 & 0.0578 & 0.0500 & 0.0481 & 0.0448 & 0.0333 & 0.0248 & 0.0219 & 0.0174 & 27.4 \\
5 & 0.0732 & 0.0537 & 0.0455 & 0.0439 & 0.0422 & 0.0353 & 0.0259 & 0.0255 & 0.0236 & 27.7 \\
6 & 0.0835 & 0.0674 & 0.0558 & 0.0503 & 0.0435 & 0.0313 & 0.0255 & 0.0217 & 0.0191 & 27.9 \\
7 & 0.0826 & 0.0685 & 0.0592 & 0.0556 & 0.0511 & 0.0405 & 0.0298 & 0.0292 & 0.0260 & 26.5 \\
8 & 0.0666 & 0.0513 & 0.0434 & 0.0421 & 0.0406 & 0.0346 & 0.0253 & 0.0249 & 0.0226 & 26.7 \\
9 & 0.0704 & 0.0529 & 0.0448 & 0.0433 & 0.0416 & 0.0339 & 0.0248 & 0.0237 & 0.0215 & 26.8 \\
10 & 0.0635 & 0.0592 & 0.0511 & 0.0489 & 0.0457 & 0.0366 & 0.0270 & 0.0263 & 0.0245 & 28.9 \\
11 & 0.1224 & 0.1050 & 0.0918 & 0.0832 & 0.0711 & 0.0498 & 0.0371 & 0.0342 & 0.0317 & 28.6 \\
12 & 0.0652 & 0.0501 & 0.0419 & 0.0403 & 0.0383 & 0.0316 & 0.0231 & 0.0223 & 0.0203 & 26.4 \\
13 & 0.0841 & 0.0712 & 0.0613 & 0.0566 & 0.0499 & 0.0373 & 0.0318 & 0.0276 & 0.0233 & 26.1 \\
14 & 0.1308 & 0.1049 & 0.0924 & 0.0865 & 0.0762 & 0.0524 & 0.0381 & 0.0356 & 0.0339 & 26.9 \\ \hline \hline \end{tabular} Note: ID is serial number of the different measurement points. T means the temperature at the middle depth.  
\end{table} 
Table 6: Measured deflection and temperature information.