TAMIL NADU

Road-laying norms given the go-by

CHENNAI Nov. 24. Normally, highway roads are laid to last for five years, with little maintenance. But rubberised and plasticised roads can last for at least two years more. The Indian Road Congress lays down specifications for roads and the Ministry of Surface Transport also monitors the guidelines for the quality of roads, according to the Highways Research Station officials.

Indian roads fail to measure up to standards, though the technology used is on a par with those used in the West, because of inadequate provision for drainage, improper surface profile during laying of roads, incorrect execution policy and improper implementation of specifications, they say.

Clay surfaces make for poor roads but most of India does not suffer from this problem. Before roads are laid, cables and pipelines for telephone, electricity, sewage and storm water drains must be laid. Storm water drains are situated on either shoulders of the road over which footpaths are built. The camber (sloping from the centre to the sides of a road) allows for rainwater to flow into storm water drains, which filter soil and send water into the natural waterways in a city or town. An ideal road should have three per cent camber or slope from the centre. Often this specification is not maintained.

The gravel forms the first layer over which hot tar is spread. Engineers and contractors who take up road laying are aware of the IRC specifications. Tar should be heated to 170 degrees and while laying, the temperature should be 100 degrees. At heating plants, tar is overheated so that it is easy to spread. This, engineers say, reduces its binding property, and in turn a road's life. Frequent digging and patchwork also affect the quality of the surface. Improper use of road pavers, designed to spread tar allowing for its binding properties, like scraping tar from the wheels of the paver also contributes to poor roads. Ordinary pavers cost Rs. 8 lakhs, whereas pavers, which also take care of the camber specification, cost Rs. 40 lakhs. Emphasis on labour cost tells on the quality of roads, the officials say.

Powdered old rubber tyres and tubes added to the tar increase the life of roads but rubberised roads are expensive as rubber costs Rs. 13,000 a tonne. Plastic waste can be used in place of rubber, according to Sushil Verma, director-general, CIPET. Collection, segregation and cleaning of plastic waste costs only Rs. 7 - 8 a tonne and as plastic's melting point is low, it can be added to bitumen without destroying its binding properties. A layer of plastic beneath the tar surface is a solution where the water levels are low.

Concrete roads are expensive, but if properly laid, require little maintenance and last 40-50 years. These roads can result in skidding besides making redundant road-laying equipment currently in use, HRS officials say.

Ideally, road-laying should be taken up at night when traffic is light and diversion is possible but this is not done as monitoring is difficult at night.

Even regular roads that do not use rubberised or plasticised bitumen would last long, if the contour levels are maintained.

In multi-storeyed complexes, the level of the buildings is raised and the entrances slope to the roads to allow rainwater to flow to the road and then on to the storm water drains. During rains, the roads become drains as non bio-degradable waste blocks storm water drains and water stagnates on the roads.

Diverting storm water drains into sewage pipes compounds the problem.

City improvement trusts and cooperative societies develop cities, but provision of basic amenities is left to municipalities and corporations, which come later into the picture.

A change in policy and educating the public besides awareness of the need for maintenance of storm water drains would ensure better roads, the officials say. All service lines and sewage or storm water drains must be on one side so that digging of roads is kept to the minimum.