Forensic Investigations for Failure of Flexible Pavements: A Case Study

Abstract

Flexible pavements undergo some form of distress during the design life. So, it becomes necessary to carry out forensic investigations to understand the causes of distresses/failures and develop an optimal rehabilitation strategy. The present study describes an investigation undertaken to determine the probable causes of distress in flexible pavements in an industrial township.

The studies conducted include visual surface condition assessment, classified traffic volume counts, axle load studies, pavement deflection studies using Benkelman beam, bituminous core cutting, laboratory characterization of samples from all pavement layers, and full-depth pit cutting at some locations on the flexible pavements.

During the condition assessment, it was observed that the condition of the pavement was poor on the entire stretch with heavy ravelling and potholes. From field and laboratory studies, it was inferred that all the pavement layers (including subgrade) were poorly compacted and did not meet the specified requirement as per the Indian specifications. Overall, the quality of the materials and workmanship was of poor quality. The pavement was heavily overloaded by commercial vehicles and a high vehicle damage factor (VDF) value was obtained. The deflection studies indicated that the existing pavement thickness was inadequate and need to be strengthened. Accordingly, suitable thickness of overlay was recommended to strengthen the pavement.

Kee** in view the structural and surface condition of the existing pavement, traffic loads and damaging factors, the short-term and long-term corrective and rehabilitation measures were suggested.