A group of engineering students from Kongu Engineering College in Erode, Tamil Nadu have come up with an innovative idea of converting concrete waste to building block to a new structure, according to a TOI report. Once an old building is brought down, the concrete waste or debris is either used as landfills or merely dumped on the roadside, which is a prevalent practice across the country. Dumping debris in unauthorized and undesignated places is an everyday scene in India. Few engineering students thought differently and came up with an out of the box concept to not only find a solution to the construction waste disposal methodology, but also of putting it into good use to building block to a new structure. If their endeavor succeeds, then we will get a major solution to the contentious issue of dumping of concrete waste all over the cities making it an eyesore.
Recently, the wannabe engineers from Kongu Engineering College bagged an award in the Carbon Zero Challenge competition, which was organised by the Indian Institute of Technology (IIT) Madras, apparently for developing blocks from concrete waste.
Professor of civil engineering, GS Rampradheep, was quoted as saying by the report that the debris can be recycled into construction material like hollow or paver blocks. “We have tested the blocks for compressive strength and found that they are stronger and more durable than conventional bricks and concrete blocks.”
According to Rampradheep, the methodology is quite simple, yet inexpensive. Initially, the students segregate the concrete waste with utmost care from the C&D debris. The second process is to crush the debris into recycled aggregates of vivid particle sizes. The third stage is to mix the crushed material with sodium silicate in order to act as an agent to reduce porosity besides increasing the durability in addition to help the material bind well. The fourth stage is to put the mixture through a carbonation process, where Co2 is pumped into it at varying pressures in a chamber. The last process is to mix the material with cement and water and then molded into blocks and subsequently they are sprayed with water again to be followed by curing by way of sun drying.
According to Prof Rampradheep, injection of Co2 will not only improve the physical properties including the density of the aggregate, but also such properties are important for the durability of the block, as most recycled bricks are known to crack faster. What is more, there is no need to add water for curing, as they have added sodium silicate to the crushed particles. Although, Chennai generates an estimated 1,200 tonnes of C&D waste every day, the Chennai Corporation had recently identified two erstwhile landfill sites in Athipattu and Pallikaranai to process the waste. Though, the technology of converting debris to construction material has been widely adopted in the West while civic body officials said less than 1% of the C&D waste is processed or recycled in Chennai.
According to the professor, this innovative technology, if adopted well will convert waste into wealth, besides cutting down on Co2 emissions. As per the report, the team has already applied for a patent for both the technology and for the equipment used for processing the waste.