Pavement Condition Index
The Pavement Condition Index (PCI) is a numerical index between 0 and 100 which is used to indicate the general condition of a pavement. It is widely used in transportation civil engineering. It is a statistical measure and requires manual survey of the pavement. PCI surveying processes and calculation methods have been standardized by ASTM for both roads and airport pavements:
- ASTM D6433 - 11: Standard Practice for Roads and Parking Lots Pavement Condition Index Surveys
- ASTM D5340 - 11: Standard Test Method for Airport Pavement Condition Index Surveys
PCI was developed by the United States Army Corps of Engineers,. The method is based on a visual survey of the number and types of distresses in a pavement. The result of the analysis is a numerical value between 0 and 100, with 100 representing the best possible condition and 0 representing the worst possible condition.
Pavement distress types for asphalt pavements include:
- Low ride quality
- Alligator cracking
- Block cracking
- Bumps and sags
- Edge cracking
- Joint reflections
- Lane/shoulder drop-off
- Longitudinal and tranvserse cracking
- Patching and utility cut patching
- Polished aggregate
- Slippage cracking
- Weathering and raveling
For relatively small pavement systems, the entire system may be surveyed. For large pavement systems, the process may involve surveying a random or representative sample of the entire system with the following steps:
- Divide the total pavement section into sample units (approximately 5000 square feet).
- Based on the number of sample units in the total section, a certain number of these units are selected to be tested. For example, if there are 40 or more sample units, 10% are tested.
- The type, extent and severity of pavement distress in each section are recorded using the ASTM Standard D 5340 method.
- The PCI of each tested sample unit is calculated using the method defined in the standard. In summary this involves calculating the distress quantities and the distress densities for each tested unit. These values are used to determine a deduct value and this deduct value is subtracted from 100 to give the PCI value.
- If the surveyed samples are representative of the overall system, the PCI of the pavement system is then assumed to be equal to the PCI of the sampled areas.