Building construction is one of the fastest growing industries in India and it puts a huge burden on its limited natural resources. There is a foraging for innovative materials that could fill up the void of natural resources. Bio-brick or agro-waste based brick is one such material that has the potential to be a sustainable and cost-effective solution. It acts as a good heat and sound insulator and at the same time has an overall negative carbon footprint. Additionally, it also acts as a deterrent to stubble burning, prevalent in northern India which causes severe air pollution. Due to its low density, it reduces dead load in high rise structures, thereby making RCC construction more economical.
Architects Priyabrata Rautray, who is also a PhD scholar in IIT Hyderabad’s Design Department, and Avik Roy, an Assistant Professor at the KIIT School of Architecture, Bhubaneshwar, have come up with a unique solution with the use of bio-bricks. They have developed bio-bricks for construction from agricultural waste products. This innovation addresses both waste management and development of eco-friendly, sustainable building materials. Guidance for the project came from Prof Deepak John Mathew, Head, Design Department, IIT Hyderabad and Dr Boris Eisenbart from Swinburne University of Technology, Australia.
How are these bio-bricks made?
The process of making biobricks starts with careful selection of the dry agro-waste like paddy straws, wheat straws, sugarcane bagasse and cotton plant. The team decided to use dry sugarcane bagasse for the first sample. The bagasse is first chopped to the desired size. A lime-based slurry is prepared, and the chopped agro-waste is added to the slurry and mixed thoroughly by hand or mechanical mixer, to create a homogenous mixture. This mixture is poured into moulds and rammed with a wooden block to make a compact brick. These moulds are left to dry for a day or two, after which their sides are removed, and the brick is allowed to dry for fifteen to twenty days. It takes approximately a month for these bio-bricks to attain its working strength by air drying.
IIT Hyderabad Bio-brick specifications
A prototype of the guard cabin was designed and executed in the space allocated by the IIT Hyderabad. It is a part of the BUILD (Bold Unique Idea Lead Development) project to demonstrate the strength and versatility of the material.
This material has good thermal and sound insulation; it is breathable and helps maintain a comfortable living condition during harsh summer or cold winters. During initial research, it was evident that vast quantities of agro-waste are generated in India, and the demand for raw material for the regular bricks is growing exponentially, leading to the loss of fertile topsoil and more air pollution. A prototype of the guard cabin was designed and executed in the space allocated by the IIT Hyderabad. It is a part of the BUILD (Bold Unique Idea Lead Development) project to demonstrate the strength and versatility of the material. This sample building is made up of Bio-Brick material with support from the metal framework.
The roof structure is made of Biobricks material over PVC sheets to reduce the heat gain. Both inside and outside the wall is cement plastered to protect the Bio-Bricks from rain. In April 2021 Priyabrata Rautray, PhD Scholar under his supervisor Prof Deepak John Mathew at the Department of Design and his team were awarded Indian Patent for the Bio-Brick material and its manufacturing technology.
To make a single block, 900 grams of sugar bagasse is used, but if this waste were to be burnt, it would release 639 grams of carbon dioxide, they claim. Moreover, the lime content in each brick allows it to absorb 322.2 grams of CO2 from the air during the curing process.
Highlights of the Bio-bricks
- Developed to counter the air pollution caused by stubble burning.
- This material exhibits excellent thermal insulation and fire-retardant properties.
- When used in roofing and wall panelling, it can effectively reduce heat gain by 5 – 6 degrees.
- Bio-Bricks are found to be 1/8 and 1/10 of weight for similar volume compared to burnt clay bricks and concrete blocks, respectively.
- Compared to burnt clay bricks, Bio-Bricks will cost about Rs.2 – Rs.3 when mass-produced.
The product took six years in the making for this Master of Product Design gradute, bio-bricks were crafted as a plausible solution to both those problems. Made out of agri-waste and sun dried to reduce pollution that arises from burning bricks, these bio-bricks are one-tenth the weight of a concrete block and one-third the price of red bricks.
Image Source – IIT Hyderabad