# Development of Korea Airport Pavement Condition Index for Panel Rating
## 3 Results  
### Deduct Value Curve and Corrected Deduct Value Curve  
The numbers of DVCs developed for the three severity levels for each distress type of six asphalt pavements and eight concrete pavements were 18 and 24, respectively. These values reflected smooth curve forms passing through each point in the distress density-average DV plots. Moreover, modeling for the CDVs including two to five distress types and severity levels was carried out. The DVs lower than 5 were not considered, as they hardly affect the pavement conditions. Figure 3: Example showing PCR, DV, and DVC for linear cracking in concrete pavement; (**a**) PCR and average PCR, (**b**) average deduct value and deduct value curve. Figures 4 and 5 show the distress density with respect to the DV of the asphalt pavements for six types of distresses, and of the concrete pavements for eight types of distresses. For comparison purposes, the DVCs of ASTM D 5340 are displayed using dotted lines. The standard deviation of the DV by the panel rating increases with the increases in the severity level and distress density. Figure 4: Comparisons between developed deduct value curves and ASTM D 5360 in asphalt pavement; (**a**) Alligator cracking, (**b**) block cracking, (**c**) reflection cracking, (**d**) longitudinal and transverse cracking, (**e**) patching and utility cut patching, (**f**) ruting. Figure 5: Comparisons between developed deduct value curves and ASTM D 5360 in concrete pavement; (**a**) Alkali Silica Reaction (ASR), (**b**) corner cracking, (**c**) cracks; longitudinal, transverse, and diagonal, (**d**) durability (”D”) cracking, (**e**) intersecting cracks, (**f**) patching, small, large, and utility cuts, (**g**) scaling, map cracking, shrinkage cracking, (**h**) spalling (longitudinal and transverse joint, and corner). In general, the shapes of the curves are important as they indicate relative effects of the distress density on the pavement conditions. The DV showed an abruptly increasing trend up to approximately 15% of the distress density; however, this trend was less evident thereafter. Comparing the developed DVC and the DVC of ASTM D 5340, they showed largely low or similar values in the \"H\" and \"M\" severities and largely high values in the \"L\" severity. The higher the density, the higher was the DV of the developed KPCI in all the three severity levels; however, the DV of the developed KPCI became lower than that given in ASTM D 5340 as it increased. The differences in the DV between the severity levels were lower than that given in ASTM D 5340. This is because of incorporating the Korean airport pavement management level that takes into consideration the importance of occurrences of distresses even at low severity, and initial distress management. Figures 6 and 7 show the effects of the different distress types of the asphalt pavements and concrete pavements on the DV. The alligator cracking of the asphalt pavements and the intersecting cracks of the concrete pavements resulted in the highest deduct value. This is due to incorporating the recognition of the panel members participating in the panel rating for FOD possibilities when it comes to the alligator cracking and severity of the intersecting cracks. Although most curves have similar shapes, their effects on the PCI may be very different. For example, the alligator cracking of the asphalt pavements has a significantly higher DV than the patching and intersecting cracks of the concrete pavements have a significantly higher DV than the spalling. Moreover, the curves change in different ways at each severity level. For example, as seen in the scaling, map cracks, and shrinkage cracks of the concrete pavements, the DV is low at the low severity level; however, the DV is the highest at the high severity level. Moreover, in case of the patching of the asphalt pavements, the DVC is relatively lower than other distresses, and it is found that an existing problem where the PCI becomes lower after the distress repair is largely solved.