India, May 24 -- The National Highways Authority of India (NHAI) has started repairing the Basai underpass on Dwarka expressway, on the recommendations of the Central Building Research Institute (CBRI), since leakage of underground water from expansion joints on the road surface were damaging the structure, officials said. A senior NHAI official said that CBRI was roped in to examine the structure and suggest remedial measures to prevent seepage of water. In order to carry out the repair work, the authority will close the carriageways alternatively from May 22 to May 29, the highway authority official said. The Gurugram traffic police also issued an advisory on Thursday about the closure of the underpass for a week. A senior NHAI official, requesting anonymity, said that a team of CBRI, NHAI and officials from L&T, which had constructed the underpass as part of the Dwarka expressway project visited the site on May 3. "The main issue under consideration was water leakage through movement joints in the underpass, caused by membrane damage and a high water-table. After looking into existing issues, experts have said that there is no structural distress to the underpass and the main issue is leakage from joints," said the official. Experts have now recommended that polyurethane grouting should be carried out for its quick-setting and water-reactive properties. "The repairs based on the recommendations by a CBRI expert, will include drilling, cleaning, injecting grout, and curing," the official said. The repairs will be carried out over one week. Following leakage of underground water, the NHAI had earlier taken up repair work of the underpass in the middle of April but due to continuous leakage of water, it decided to rope in the services of experts. The four-laned Basai underpass at Dwarka expressway has been built at a cost of Rs.24 crore and is 548 metres in length. It connects the Basai Hero Honda Chowk and adjoining areas with developing sectors across the Dwarka expressway and it helps residents of sectors 102, 102A, 103, 106, and other adjoining areas to commute with ease....