Scientists at Nanyang Technological University, Singapore (NTU Singapore) have created renewable, sustainable ‘biocement’ made entirely from waste materials, making it a greener and more sustainable alternative to regular cement.
The NTU scientists have used two common waste materials, industrial carbide sludge (the waste material from the production of acetylene gas) and urea (from the urine of mammals) to create the biocement.
Making the biocement involves creating a reaction between urea and the calcium ions in industrial carbide, which then forms a hard solid, or precipitate. The carbide sludge, combined with acid, produces soluble calcium. Urea is then added to the soluble calcium to form a cementation solution. Finally, a bacterial culture is then added to this cementation solution which breaks down the urea in the solution to form carbonate ions.
These ions react with the soluble calcium ions to form hard calcium carbonate, just like that naturally found in chalk, limestone, and marble. The reaction takes place in soil, so that the precipitate bonds soil particles together and fills the gaps between them, creating a compact mass of soil. This results in a strong, sturdy and less permeable block of biocement.
The advantages of creating a biocement this way include:
- Biocement production is greener and more sustainable than the methods used to produce traditional cement. For example, unlike traditional cement-making (which involves the burning of raw materials at extremely high temperatures over 1,000 degrees Celsius and producing a large amount carbon dioxide) the biocement can be produced at room temperature without burning anything. This makes the process greener, less energy demanding and carbon neutral.
- Carbide sludge is seen as waste material (in Singapore) and is abundant, adding to the sustainability of biocement production. This means that there’s no need for the mining of limestone (which is a finite resource) and, therefore, there’s less of an impact on the natural environment and ecosystem.
- If scaled-up, the process would cost less than traditional cement making.
Added Advantage – Restoring Monuments And Strengthening Shorelines
The NTU scientists have also highlighted the fact that the colourless nature of the bacterial culture and cementation solution means that when applied to soil, sand or rock, their original colour is preserved. This could make the process ideal for restoring old rock monuments and artifacts, and even strengthen the sand on the beach to prevent erosion, road repair, sealing gaps in underground tunnels to prevent water seepage, or even as cultivation grounds for coral reefs as coral larvae like to grow on calcium carbonate.
What Does This Mean For Your Organisation?
Considering that 4.4 billion metric tons of cement was produced worldwide in 2021, and how much carbon is produced in the process, and how many materials are used in it (and the impacts of mining them) – calcium, silicon, aluminium, iron, and others – biocement could be a real breakthrough. The fact that it’s cheaper (at scale) as well as being much greener and more sustainable could mean that it is a widely accepted substitute that benefits us all in terms of helping to tackle global warming as well as creating more buildings for a growing population. Biocement is still in its early stages, but it certainly looks like a sustainable substitute for traditional cement making. It could also create other business opportunities and be useful in a wide variety of environmental projects.
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