CRRI to probe cracks on newly built NH-208 stretch in Tripura

The National Highways and Infrastructure Development Corporation Limited (NHIDCL) has sought the expertise of the Central Road Research Institute (CRRI) after significant cracks and pavement damage emerged along a newly-constructed stretch of National Highway 208 in Tripura.

A CRRI team is expected to reach the state within the next 15 days to carry out a detailed site investigation.

Addressing the media, the Secretary of the Tripura Public Works Department (PWD) Kiran Gitte said the damaged section lies between Kamalpur and Khowai, where a 25.6-km stretch of the highway was completed on April 17, 2023. Since then, the project has been under a five-year Defect Liability Period (DLP).

He said that the PWD and NHIDCL jointly oversee the construction and upkeep of six national highways in Tripura, covering a total of 793 km. Of this, 43 km is managed by the state PWD, with the rest under NHIDCL’s jurisdiction.

According to the official, signs of pavement settlement and distress first appeared after heavy rainfall in August 2024, particularly in the Khowai Bypass area between Km 96.000 and Km 97.000. Subsequent inspections revealed that approximately 12 km of the highway had suffered structural damage, marked by alligator cracking and upheaval of the pavement.

“The highway was built under the Engineering, Procurement, and Construction (EPC) model, with the contractor adhering to specifications prescribed by the Ministry of Road Transport and Highways (MoRTH) and the Indian Roads Congress (IRC). Materials were tested both on-site and by NABL-accredited third-party laboratories, and construction quality was monitored by an Authority Engineer and an Independent Special Project Monitoring Unit. A Completion Certificate was issued upon project delivery in April 2023”, said Gitte.

Gitte said preliminary assessments have traced the root of the damage to failures in the subgrade layer of the road. The EPC contractor has attributed this to a sharp rise in groundwater levels, which led to soil saturation and a reduction in load-bearing capacity.

“To investigate further, NHIDCL has proposed that CRRI conduct an in-depth study, and approval from the corporation’s New Delhi headquarters is awaited. Meanwhile, rectification efforts are already underway. The contractor has mobilized equipment and manpower over the past two months to excavate and replace the subgrade soil up to two meters deep. The repair work involves installing a sand-based drainage barrier to block capillary moisture and reapplying a new bituminous layer. Officials who conducted a joint inspection of the site said the repairs are progressing and are expected to be completed within the next two month”, he added.