Railways experiment with cost-effective fly ash sleepers
The Research, Design and Standards Organisation (RDSO) of Indian Railways is experimenting with cost-effective sleepers for railway tracks. At present, railway sleepers are made with cement concrete. Now, the RDSO, in collaboration with IIT-Kanpur and NTPC, is planning to use fly ash in the sleepers, which will not only make them more durable, but also cost effective. An initiative of NTPC, the project was undertaken by RDSO in January 2010, and the sleepers will undergo lab tests in the next three months before going for field trials.
Fly ash is a residue of coal-based thermal power plants and is generally considered a waste. However, it is known to acquire cement-like properties when mixed with lime and water because of its pozzolanic characteristics, said V K Mathur, Head of Ash Utilisation Division, NTPC.
India produces 150 million ton fly ash every year and by 2012, the production is expected to reach 200 million tons. Mixing 25 to 30 per cent of fly ash gives 20 per cent more durability to the cement structure as the fly ash particles, being smaller in size than the cement particles, settle in the smallest of voids in a cement structure and make the structure more condense, Mathur told The Indian Express.
He was in town to participate in the two-day UIC Asia Workshop on Optimisation of Pre-stressed Concrete Sleepers organised by the International Union of Railways in collaboration with RDSO. This is the first time that railways organised an international workshop in Lucknow and more than 80 delegates from across the country, as well as from Germany and Australia, participated in it.
“We produce around one crore sleepers every year and if the experiment is successful, it will reduce the cost of production of each sleeper by approximately Rs 30, which will mean an overall cost saving of Rs 30 to 35 crore per annum for India Railways,” said A K Singhal, Executive Director (Track), RDSO.
“In the long run, this will also gain carbon credits for RDSO as it will reduce 0.15 million tons emission of carbon dioxide per annum,” Mathur said. Fly ash is also expected to reduce lime requirements in the process by 0.15 million tons, he added.
“The lab tests on sleepers made of 30 per cent fly ash is being done in IIT-Kanpur and if all goes well, we will be ready for its field trial in the next three months. The first trials on main track will be done in the vicinity of RDSO, Lucknow,” said Singhal.