This model has been validated against temperature data from the LTPP database for two test sites with different environmental conditions, one of them (section 1-0101) in Alabama and the other (section 31-3018) in Montana.
For both cases the structure analysed is that described in Table 1.
| Layer | Thickness [m] | Specific Heat [J kg-1 K-1] | Thermal Cond. [J m-1 s-1 K-1] | Density [kg m-3] |
| HMA | 0.2 | 1670 | 1.40 | 2400 |
| Granular | 5.2 | 840 | 0.76 | 2100 |
Table 1: Validation – pavement structure
The input parameters used are:
| Cloud base factor | 0.9 |
| Vapour pressure | 1.33mbar |
| S. s. w. absorptivity | 0.98 |
| S. emissivity | 0.93 |
Table 2: Validation – inputs
The highest value for surface absorptivity was chosen as it corresponds to a newly constructed (or re-surfaced) road, which is the case of these test sites.
1.1.1.1 Alabama – latitude of 32.61°
The Figure 1 to Figure 5 show how the predicted monthly average temperatures compare to the measured daily ones at different depths for a test section in Alabama. In this case, measured temperatures were not available after the 12/10/1996.
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Figure 1: Alabama – Prediction of surface temperature
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Figure 2: Alabama – Prediction of temperature at 0.2m of depth
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Figure 3: Alabama – Prediction of temperature at 0.4m of depth
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Figure 4: Alabama – Prediction of temperature at 1m of depth
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Figure 5: Alabama – Prediction of temperature at 2m of depth
1.1.1.2 Montana – latitude of 47.41°
Figure 6 to Figure 10 refer to a test site in Montana, with temperatures noticeably lower than our previous example.
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Figure 6: Montana – Prediction of surface temperature
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Figure 7: Montana – Prediction of temperature at 0.2m of depth
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Figure 8: Montana – Prediction of temperature at 0.4m of depth
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Figure 9: Montana – Prediction of temperature at 1m of depth
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Figure 10: Montana – Prediction of temperature at 2m of depth
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