Selection of Pavement Section Pavement Condition Survey

61 The surface condition of a pavement at any time reflects the degree of damage caused by traffic and the environment based upon a visual evaluation of the pavement surface. The surface condition rating is useful as an input for predicting the remaining life of a pavement. It also assists in the preliminary evaluation and programming of appropriate maintenance and rehabilitation treatments AGRA Earth, 1997. The evaluation of pavement performance is a complex task and it is important for pavement design, rehabilitation, and management. Generally speaking, the main components of the pavement performance include the evaluation of pavement roughness, distress, friction and structure.

3.4.3 Assessment and Limitation:

During the field condition surveys and validation of the PCI, several questions are commonly asked about the identification and measurement of some of the distresses. The answers to these questions for each distress are included under the heading “How to Measure”see chapter II. However, the most frequently raised issues are addressed below ASTM standard D 6433, 1999: - If alligator cracking and rutting occur in the same area, each is recorded separately at its respective severity level. - If bleeding is counted, polished aggregate is not counted in the same area. - If a crack does not have the same severity level along its entire length, each portion of the crack having a different severity level should be recorded separately. If, however, the different levels of severity in a portion of a crack cannot be easily divided, that portion should be rated at the highest severity level present. - If any distress, including cracking and potholes, is found in a patched area, it is not recorded; its effect on the patch, however, is considered in determining the severity level of the patch. - Significant amount of polished aggregate should be present before it is counted. 62

3.4.4 Analysis of data

Figure 3.4 Analysis steps Record data in data sheet Calculate: Total quantity each type and each level Density each type and each level Determine DV Procedure to determine CDV: List the individual DV descending order. Determine m ≤ 10 Determine total DV Reduce the smallest value to 2 Determine q Determine CDV Yes No Determine CDV: If none or only one individual deduct value is greater 2 Calculate PCI: PCI=100- max CDV