The Pavement Condition Index (PCI) is the most important element of determining pavement conditions. It is at the heart of the Zimmer approach to managing pavements. The PCI was developed at the Corps of Engineer’s Construction Engineering Research Laboratory (CERL) in Champaign, Illinois by my friends, Mo Shahin, PhD. and Starr Kohn, PhD. It is an objective, repeatable, visual rating system which matches the average numeric rating that a group of experienced pavement engineers would subjectively rate a pavement. If you are ex-military, you may know the term, “G.I. proof.” Meaning the inspection procedure is easily learned. Zimmer has relied on this approach for 35 years.
The rating goes from 100 for a new, distress-free pavement to 0 for a failed pavement.
The Figure presents the five steps in calculating the PCI number. Originally all the steps were done by hand but are thankfully now computerized into a program called PAVER. The key to the PCI’s usefulness is the identification of a pavement distress; a determination of the severity level; and a measure of each distress and severity quantity. These three items are elemental to a useful rating system.
The PCI gives us the ability to monitor pavements; project future conditions; and calculate current and future budgets. We will discuss these uses in more detail in future postings.
Figure from: Asphalt Surfaced Roads & Parking lots, PAVER Distress Identification Manual, Developed by: US Army Corps of Engineers ERDC-CERL, M.Y. Shahin and S.D. Kohn.