Hastily laid roads show potential for potholes during monsoon in Bengaluru

While many roads are getting asphalted on a war footing ahead of the Assembly polls and monsoon, citizens point to substandard gradation leading to multiple voids.

Experts warn that the voids would gradually blossom into potholes once the rains start.

Inadequate mixture of bitumen content was reported in parts of Mahalakshmi Layout, Magadi Road, Malleswaram, New BEL Road, HSR Layout, Gandhinagar, Shivajinagar, and CV Raman Nagar where the civic body recently laid new roads.

Experts blame inadequate gradation mix, design mix, and temperature for small voids on new roads. This issue worsens when mixtures are prepared at drum-mix plants.

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While some of them are computerised to ensure the right mixture, some do not use the right amount of fine aggregates because they cost more per tonne than coarse aggregates, BBMP sources said.

“If the gradation mix is not taken care of, roads will see problems such as mix rutting and voids. This is enough for the water content to absorb and destroy the road,” an expert in road-building works told DH.

He said a newly laid road has a life of over eight years in general and could last over four years in a traffic-heavy city like Bengaluru, but that does not usually happen.

Two types of tests

Srikanth Channal, who heads the Bengaluru chapter of the Association of Consulting Civil Engineers, said that the civic body was expected to conduct two types of tests while asphalting the roads.

“There are a lot of technicalities involved, including milling, spraying of coat, base and finishing carpets, etc. These works must be done under the supervision of professional engineers, which we do not see at all,” he said. Channal said road construction goes beyond just asphalt laying; the geometry of the road, kerb placement, median centre, and footpath repairs are all critical.

BBMP’s Engineer-in-Chief B S Prahlad said a separate division had been formed to examine specific road repair issues, but such complaints are rare.