Published Paper Details:

In the age of sustainability, it is necessary to set a focus on low carbon footprint to build an ecological world. The conventional burnt clay brick manufacturing firing process develops 750 million tonnes of Carbon Dioxide emissions annually. Being a very fast and growing economy, infrastructure development becomes an important part of our country and so does the need for construction materials. The disasters due to climate change are not new to countries like India. According to UN Climate Change News, dated 5 July 2018, the cement industry accounts for 5-6% of global greenhouse emissions. Many advanced investigations are being done to develop construction materials; one such investigation is by incorporating microorganisms that are capable of precipitating calcium carbonate (CaCO3) which can act as a binding agent between aggregates. Microbe-induced calcium Carbonate Precipitate (MICP) process is used for the purpose. MICP is a bio-geochemical process that induces calcium carbonate precipitation. Several mechanisms have been identified by using bacteria that can induce calcium carbonate precipitation, including urea hydrolysis, denitrification, sulphate production, and iron reduction. In this study, non-pathogenic ureolytic bacteria like Bacillus subtilis are utilised to induce urea hydrolysis that can help to manufacture a brick. Bacillus subtilis can survive in alkaline environmental conditions and also it can survive both in aerobic and anaerobic conditions which makes it special to use in this particular research. It is a common soil bacterium that is also found in the intestinal tracts of humans, thus not harmful to use in construction. The brick is manufactured from different combinations of base aggregates. The steel slag is used as one of the base aggregates for brick manufacturing and the other is clay. Steel slag is a waste project from the steel industry and production in India accounts for about 12 million tonnes per annum. The amount of steel slag produced by different steel industries is 150-200 kg per tonne of steel produced. This steel slag is dumped on land and pollutes the environment. The same can be used as a method to alter a waste product to a wise product. Clay is abundantly available in India, thus making the bio-brick economical. The brick is also reinforced with naturally and locally available fibres such as jute and cocopeat. The addition of these fibres can improve the compressive strength of bio-brick. This is an eco-friendly and energy-efficient method of brick manufacturing. The compressive strength, water absorption test and efflorescence test are conducted to support the strength development in bio-brick. As well as SEM-EDX analysis was done to identify the surface morphology and elemental composition. The study was conducted using 1%, 2%, 3%, 4% and 5% reinforcement concentrations and the maximum compressive strength for jute was 30.08 N/mm2, obtained at 2% concentration, on the 28th day. For cocopeat as reinforcement, maximum compressive strength was 15.1 N/mm2, obtained at 3% concentration and at the 28th day. The water absorption for these bio-bricks was 12 % and 15 %, for cocopeat and jute respectively, with no efflorescence for any bricks.