Sandstone water absorption norms halt NDMC construction projects
A CPWD-imposed limit on sandstone water absorption has stopped New Delhi Municipal Council from finalising many civil construction works. Engineers at the council want the water absorption limit of red and white sandstone to be increased.
The specification says red and white sandstone used in construction work should not have water absorption above 2.5 per cent of the total weight of the stone. NDMC has proposed that the water absorption limit of sandstone should be increased to 6 per cent. "The proposal is to allow 6 per cent water absorption in red/white sandstone used in various works against the permissible limit of 2.5 per cent, as specified by CPWD," reads the proposal, which will be placed before the council.
When contacted, CPWD Director General Ashok Khurana said: "The current limit is 2.5 per cent, but our officials have put up a proposal for extending the limit of water absorption to 5 per cent and a decision will be taken soon."
"A number of construction projects, such as pavements and buildings, have not been finalised because the sandstone failed to meet CPWD's absorption limit in tests," a senior official said.
NDMC engineers said it has become impossible to get sandstone with water absorption capacity below 2.5 per cent. "Red sandstone used in CPWD works does not conform to this specification and the norms had to be relaxed. The approval was given by CVC in 2011 and the previous engineer-in-chief also suggested that samples collected jointly by the field executives from mines failed in the required test because the water absorption limit was found to be between 4.21 per cent and 5.7 per cent of the total weight of the stone, the official said.
NDMC cannot take a decision on the water absorption limit specifications. Hence, the matter was referred to CPWD.