# Development of Korea Airport Pavement Condition Index for Panel Rating
## 2 Materials and Methods
### Panel Rating  
Practical photograph data of each distress type were collected from the PMS data of the Korean airports. A conclusion was reached that sample units comprising an asphalt pavement of size 450 m\({}^{2}\) and a concrete pavement comprising 18 slabs would provide adequate pavement areas for PCI evaluation, and the calculation was performed by conducting a preliminary analysis on the collected data with the help of expert discussions. The sample unit was sufficiently wide for meaningful distress measurement. The distress density was determined by dividing the surface area of the particular distress measured for a particular severity level by the total area of the sample unit in case of the asphalt pavement. As the linear cracking (longitudinal or transverse) is measured in terms of length (m), the distress area was calculated considering an affected width of 0.3 m to determine the density. The distress density of the concrete pavement was determined by dividing the number of slabs with a particular distress of a particular severity level by the total number of slabs of the sample unit. The evaluation was carried out for five distress density levels. The distress values of each asphalt pavement were evaluated for levels in the ranges of 0.1-1.5%, 1.6-4.9%, 5-14.9%, 15-39.9%, and 40-75%, and the distress values of each concrete pavement were evaluated for density levels of 1/18, 2/18, 4/18, 8/18, and \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{**Asphalt Pavement**} & \multicolumn{2}{c}{**Concrete Pavement**} \\ \hline
**Distress Type of Deduct** & **Distress Type of Existing** & **Distress Type of Deduct** & **Distress Type of Existing** \\
**Value Curve Developed** & **Deduct Value Curve Used** & **Value Curve Developed** & **Deduct Value Curve Used** \\ \hline  & \begin{tabular}{c} Bleeding \\ Corrugation \\ Depression \\ \end{tabular} & \
\begin{tabular}{c} Alkali Silica Reaction (ASR) \\ Corner Cracking \\ Cracks; Longitudinal, \\ Transverse and Diagonal \\ Durability (“D”) Cracking \\ Intersecting Cracks \\ Patching and Utility Cut \\ Patching \\ Rutting \\ \end{tabular} &
\begin{tabular}{c} Blowup \\ Joint Seal Damage \\ Popouts \\ Pumping \\ Settlement or Faulting \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Distress Type of Developed Deduct Value Curve. 12/18. This is based on the fact that sections with a distress density of 80% do not exist in Korean airports. The panel independently and subjectively carried out the evaluation in accordance with the rating criteria, as listed in Table 1. The pavement condition rating (PCR) evaluated by the panel was calculated for each sample unit and for each density level [24]. Considering the deviations within the panel, the PCR was calculated as moving average (\(\overline{\text{PCR}}\)) excluding the bottom and top 10 percentiles. Here, moving average (MA) is a traditional statistical method for analyzing the trend of time series data fluctuations, which can be used to predict and smooth data [25]. The MA model removes the anomaly data in the manner of averaging neighboring samples [26]. The average DV was calculated using Equation (3). \[\text{DV}\ =100-\overline{\text{PCR}} \tag{3}\]  
where DV is the average DV, the value 100 is a constant depending on the desired maximum scale value, and \(\overline{\text{PCR}}\) is the average PCR excluding the top and bottom 10 percentiles. Figure 3a shows the PCR with respect to the distress density of severity \"H\" for concrete pavement cracks (longitudinal, transverse, and diagonal), the average (\(\overline{\text{PCR}}\)) excluding the top and bottom 10 percentiles, and the Figure 3b shows the DVC, which is a regression curve passing through the average DV. In case of two or more distress types or severity levels in a pavement, the DVs cannot simply be added, and the TDV must be adjusted by incorporating the number of deducts (or the distress types and the levels of severity) and the magnitude of the sum of deduct values.