After trying out plastic and the Crumb Rubber Modified Bitumen methods, Greater Hyderabad Municipal Corporation (GHMC) is now utilising anti-stripping agents, a chemical-based solution while laying roads to ensure durability. Telangana Today published news on how the process has been developed.
Anti-stripping agent is a chemical that reduces water induced damage to bituminous roads and pavements. It acts like an adhesive and enhances the affinity between the metal (gravel) and bitumen even during rains.
Ensuring quality and longevity of roads is proving to be a challenge for GHMC, especially during monsoon. During rainy season, roads in the city get damaged as bitumen and metal lose bonding and eventually potholes are formed on the surface.
In a bid to address these issues, GHMC is now planning to use anti-stripping agents in the bitumen hot mix while laying roads.
A private company gave a demonstration to the GHMC engineering wing on Wednesday about the benefits of using anti-stripping agents, cost effectiveness and the procedure to be followed while mixing with bitumen hotmix.
“The company representatives informed that it has been used in Bangalore and a few North Eastern States and proven to be successful. Hence, we are planning to use it here as a pilot project,” said GHMC Chief Engineer (Maintenance) Ziauddin.
The idea is to use the anti-stripping agent while laying roads in at least one stretch in each municipal circle. In terms of cost and material, it does not result in huge additional input cost as very less amount of chemical is to be used, he explained.
The anti-stripping agent has to be mixed with the bitumen hot mix at the mixing plants and then it has to be laid on the road surface. Works should commence in a couple of days, he said.
How is bitumen hot mix prepared?
Bitumen and gravel are heated separately at temperatures ranging between 170 and 180 degrees and mixed in the hot mix drum at the plants. The hot mix has to be laid on the road while temperature hovers around 140 degrees.
Rolling works are to be taken up only when the temperature recedes to 100 degrees. This is the reason, workers are made to wear gumboots, gloves and follow other safety measures while executing works.
Plastic and CRMB roads
Laying emphasis on longevity of roads, GHMC has earlier re-carpeted few stretches with plastic road and Crumb Rubber Modified Bitumen methods in the city.
The first plastic road on the Uppal-Nagole stretch was laid last year and buoyed with the success, the civic body laid more plastic roads in different areas such as B N Reddy Nagar, L B Nagar, Mansoorabad, and Jubilee Hills.
The roads were laid using an amalgam of bitumen and plastic, especially polythene covers. Usage of plastic waste in laying roads helps in controlling water seepage beneath the road surface, besides reducing the expenditure, authorities said.
This apart, the municipal corporation laid a Crumb Rubber Modified Bitumen (CRMB) eco-friendly road from NCC Gate to the Police Station on the Osmania University campus early this year.
Under the CRMB technology, GHMC is utilising the amalgamation of old and discarded four wheeler tyres and the conventional bitumen for laying road. The old tyres are burnt and reduced to form a liquid and then mixed with bitumen to 20 to 25 per cent proportion.