India, Aug. 8 -- An expert team from the Indian Institute of Technology (IIT), Kharagpur, led by KS Reddy, reached the expressway on Thursday and has begun a forensic engineering investigation to determine why the pavement continues to collapse despite the highway being newly built. Speaking to Hindustan Times, Gautam Vishal said the team would collect samples on Saturday for laboratory testing and carry out a scientific failure analysis. The experts are examining every layer of the pavement-from the bituminous surface to the granular base, sub-base and embankment-to establish whether the distress has been caused by poor-quality construction material, inadequate compaction of earthwork, weak foundation layers, faulty pavement design, drainage failure or lapses during construction. The team will also study soil samples, pavement cores, moisture content and drainage systems to determine whether water seepage weakened the embankment or whether structural deficiencies existed from the outset. Advanced forensic techniques, including laser-based pavement profiling and laboratory testing of construction material, are expected to form part of probe. The findings are likely to determine responsibility for the repeated failures and could become the basis for further action against concessionaire, consultants and officials. NHAI has acknowledged deficiencies in earthwork, drainage arrangements and quality control during construction. Despite these shortcomings, officials allowed the project to progress. Following the collapse, NHAI suspended toll collection, issued a Non-Performer Notice to PNC Infratech proposing to debar it from future projects, and initiated disciplinary proceedings against officials and the independent engineer associated with the project. htc...