Researchers from IIT Madras, South African universities work to reuse construction debris in new structures

Recycling concrete that would otherwise be discarded could help reduce waste, the researchers said; they are now disseminating their model to governments and the construction industry

The researchers’ aim is to reuse construction debris. File photograph used for representational purposes only | Photo Credit: JOTHI RAMALINGAM B

Researchers from the Indian Institute of Technology Madras’ (IIT-M) civil engineering department, along with their counterparts in South African universities, are working to make the reuse of construction debris to build new structures, the norm.

The researchers wanted to study the properties of new concrete that can emerge from debris, and test its durability, said Manu Sathanam, dean, industrial consultancy and sponsored research at IIT-M. His research partner in the institute is Ravindra Gettu, also a civil engineering professor.

The duo is working with Yunus Ballim, emeritus professor, school of civil and environmental engineering, University of Witwatersrand, Johannesburg and Mark G. Alexander emeritus professor in the civil engineering department from the University of Cape Town.

The collaborative research began in 2003. The researchers have developed a monograph and video lectures and have demonstrated how concrete that is wasted during construction projects can be recycled, making it new, useable concrete, thereby preventing wastage.

The researchers want this model to spread and so, the construction industry has been allowed to use their monograph for free. The researchers also recently released video lectures on the subject for the National Programme on Technology Enhanced Learning (NPTEL). “We wanted to disseminate more information about utilising construction debris as aggregated new concrete,” Prof Manu Santhanam explained.

“The monograph talks about processing, how the property of concrete changes when we replace natural material and its impact on long-term durability,” Prof Santhanam said, adding that reuse would prevent the waste of natural resources. “We want to look at this from the perspective of driving policies, instead of it remaining a laboratory experiment,” he said.

Several State government agencies are consulting with the researchers, according to Prof Santhanam. “The Tamil Nadu government reached out with respect to understanding these alternative construction methodologies,” he said especially in terms of its technical abilities and affordability. The agencies include the Public Works Department and the Urban Housing Department. “We have done an on-site demonstration of how the wasted concrete in construction projects can be recycled to get it back into usable, new concrete for Chennai Metro Rail Limited,” he added.

For some time now, construction debris is being used under the surface of asphalt in road-laying projects, but it is necessary to show evidence that the aggregates are durable, the researchers said. However, a policy decision is needed for the recycling of waste to take full effect. The researchers said they are now working towards this.