Two and two can make five. The old saying in Hindi of the whole being more than the sum of its parts has been proven right by two teachers at the Visvesvaraya National Institute of Technology (VNIT). One a civil and another a chemical engineer, they have put their expertise together to develop environment friendly, energy efficient materials from industrial and agro waste like sugarcane bagasse and construction waste. They have used these materials for making false ceilings and in interior designing as well as demonstration houses.
The idea originated during their visit to a paper mill about two years ago. They saw a huge amount of waste generated from the mill and decided to reuse it. Now they have developed extremely light weight and energy efficient bricks from paper waste.
“We decided to make bricks from the waste mainly looking at almost a 30 per cent shortage of bricks. Also, we needed alternative materials that could fit into our concept of green construction. After the newspaper waste bricks, we made similar thermally insulated bricks from agro-waste or sugarcane bagasse - and also a mixture of waste material generated commonly at any construction site,” said Rahul Ralegaonkar, associate professor of civil engineering at VNIT.
Sugarcane bagasse is generally burnt in furnaces and elsewhere resulting in ash. This ash is similar to the fly ash used to make bricks.
His co-researcher Sachin Mandavgane, an associate professor in chemical engineering, says he does not claim to replace the conventional construction material with his recycled paper mill waste ( RPMW) bricks. He is instead confident that the material is an ideal one for false ceilings and partition walls used in interior design. These bricks also cost just over half the conventional brick.
“Of the total newspaper waste generated, about 15 per cent cannot be recycled again and goes as complete waste. We use this to make our bricks, which are extremely light weight, low cost and environment friendly,” he said.
To promote the idea, head of civil engineering department V A Mahisalkar, with support from VNIT director S S Gokhale, created a Forum for Promotion of Green Buildings in December last year. It will not only propagate these ideas but also attract new ones.
“We got good responses in the three activities we organized so far. Students came up with new ideas. There is much scope for green buildings in future,” he said.
The institute has already introduced the concept of energy efficient buildings and sustainable construction in the syllabus. Forum plans to start a newsletter to promote green buildings.
Ralegaonkar is also promoting conservation of energy in both existing buildings and the ‘green’ ones. He is using ‘occupancy sensors’ for the purpose. They automatically turn lights and fans on or off depending on whether is room is occupied or not. For him, these are ‘smart intelligent buildings’. The two researchers also realize that these materials cannot replace conventional materials immediately. The raw materials used by the researchers are otherwise sent to land fills.
“Till the time newspapers are there, there will be enough raw material for us to make these bricks,” says Mandavgane.
These have been developed under two projects funded by the department of science and technology (DST), Government of India. The projects have also resulted into creation of a software that can be used to calculate the carbon emissions from different building materials and the equipment inside them.
The researchers have also developed a technique for making false ceilings using a combination of aluminium sheets; mortar saw dust and thermocol along with a fiber mesh. Since thermocol is not energy efficient and environment friendly material, they plan to replace it with a better material. Another of their innovative ideas is the use of reflecting tile materials on the terrace to reduce penetration of heat. For protecting the buildings from excessive heating they have also integrated the double glaze window concept into the structures.
