The Task Force on ‘Quality assurance in public constructions’ has found major deficiencies in several road works executed by the Bruhat Bangalore Mahanagara Palike.
The team, comprising three engineering experts — C.E.G. Justo, B.R. Srinivas Murthy and I. Ravindranath — inspected six major roads in the city two years ago. The defects detected in the works have gone into a report submitted to the Karnataka State government.
According to the team, the HMT Main Road from State Bank of India to the HMT, has an average deficiency in thickness of dense bitumen macadam (DBM) and the bitumen concrete (BC) layers of about 15 mm, while gradation of bitumen concrete mix is inadequate.
On S.R. Road from Government Soap Factory to KLE Dental College, an average deficiency of 20 mm has been found in the thickness of DBM and BC layers and the gradation of mixes were not satisfactory. It was a similar case with Mount Joy Road from Srinagar to K.R. Hospital Road, but deficiency in thickness here was found to be 15 to 20 mm and gradation of DBM mix at one location and that of BC mix was found inadequate.
On 11th Main Road-Malleswaram from Sriramapuram bridge has an average deficiency in thickness of DBM and BC layers of 25 to 28 mm. Gradation of DBM mix at lone location and that of BC mix was found to be unsatisfactory.
The quality of work on the stretches of 1st Main Road from Hampinagara to Swimming Pool Road and Jalahalli West Main Road from Ayyappa Temple to Gangamma Circle has also been termed average. Average deficiency in thickness of DBM and BC layers in these roads was 16 to 26 mm and 28 to 33 mm respectively, and gradation of BC mix was found to be inadequate.
The experts felt that the aggregate gradation was not satisfactory in most road works. It appears the contractors were unaware of the importance of sticking to the specifications. Due to such anomalies, the service life of the strengthened pavement layers will deteriorate faster.
