Australian scientists are finding ways to use coffee grounds to make stronger concrete.
In 2012, researchers stumbled onto an incredible discovery. When mixing biochar (burnt organic materials) with mortar mixtures, it improved the compressive strength of building materials. Their initial tests began with using biochar from bamboo and other woods. The results were promising, and researchers continued their experiments using different organic materials.
Then almost a decade later, researchers at Australia’s RMIT University made a major breakthrough. They experimented with adding biochar made from used coffee grounds to concrete mixtures. The results were shocking: The coffee grounds made concrete stronger. But that’s just one of the advantages they discovered from using coffee grounds in concrete mixtures. Here are the reasons why the constriction industry should consider changing the way that they manufacture concrete to include used coffee grounds.
Advantages To Using Coffee Grounds In The Concrete Manufacturing Process
Used coffee grounds have the potential to revolutionize the concrete industry. Here are the main advantages of adding coffee grounds to concrete mixes.
Coffee Grounds Can Make Stronger Concrete
Can coffee grounds really strengthen concrete? Yes. Replacing 15% of the sand in concrete mixtures with biochar made from coffee grounds increased the concrete’s strength by 29.3%, according to engineers at Australia’s RMIT University.
The researchers are now working with local governments to find ways to use this new stronger concrete in future infrastructure projects. This could include using it to make roads, bridges, and buildings that are stronger, more durable, and more sustainable.
Reduces Coffee Waste From Landfills
Adding used coffee grounds to concrete mixtures also helps reduce landfill waste. Australia alone produces about 75,000 tons of coffee waste each year. Diverting used coffee ground to concrete manufacturers is good for the environment because it reduces the amount of coffee waste in landfills.
If major coffee retailers, like Starbucks, agreed to recycle their coffee grounds, this could make a huge difference in reducing coffee waste in global landfills.
Coffee Biochar Helps Reduce Greenhouse Gases
Coffee biochar is created by roasting coffee grounds in the absence of oxygen, which prevents carbon dioxide from being produced. This process is called pyrolysis. Pyrolysis converts the biomass into a stable, carbon-rich material that can be used in a variety of applications, including concrete production.
Traditional concrete additives, such as fly ash and slag, are often produced using industrial processes that release greenhouse gases into the atmosphere. In contrast, the production of coffee biochar can be done in a relatively low-energy way, and it can actually capture carbon dioxide from the atmosphere.
Cement production is responsible for about 8% of global carbon dioxide emissions. This is because cement is produced by heating limestone in kilns, which releases carbon dioxide into the atmosphere. The use of coffee biochar in concrete has the potential to significantly decrease cement production and subsequently minimize the carbon footprint of the concrete manufacturers.
Reduces Demand For Sand Mining
Concrete is the most widely used building material in the world, and sand is a major component of concrete. Every year, billions of tons of sand are mined for concrete production. But sand mining can lead to deforestation, erosion, and coastal flooding. It can also displace local communities and damage ecosystems.
Using coffee grounds as a partial sand substitute could help to reduce the amount of sand that needs to be mined for concrete production. If coffee grounds were used to replace even 10% of the sand in concrete, it would save millions of tons of sand from being mined each year.
A More Energy Efficient Concrete Production Process
According to researchers at Australia’s RMIT University, incorporating biochar into the concrete manufacturing process is more energy efficient compared to traditional methods. This is because the operation process can be done at lower temperatures.
They found that the perfect temperature to blend the composite concrete with used coffee grounds is 350 degrees.
Coffee Grounds Help Improve The Thermal Insulation Properties Of Concrete And Reduce Heat From Urban Areas
Concrete has a relatively high thermal conductivity, which means that it can easily transfer heat from one side to the other. This can be a problem in urban areas, where concrete buildings and roads can absorb and trap heat from the sun, making the city hotter.
Coffee grounds can be used to improve the thermal insulation capacity of concrete by reducing its thermal conductivity. This is because coffee grounds are a porous material, and air is a good thermal insulator. When coffee grounds are added to concrete, they create small air pockets in the material. These air pockets trap heat, preventing it from transferring through the concrete.
Studies have shown that adding just 17% coffee grounds to concrete can reduce its thermal conductivity by up to 50%. This means that concrete with coffee grounds will be much less likely to absorb and trap heat from the sun, making it a more effective thermal insulator.
Coffee Biochar Concrete Can Help Absorb Odors And Pollutants
Coffee beans are porous, meaning they have many tiny holes in them. These holes allow the beans to absorb odors and pollutants from the air and water around them. When coffee beans are roasted to create biochar, their ability to absorb odors and pollutants is further enhanced. This is because biochar is a highly porous material with a large surface area. This nitrogen-rich large surface area allows biochar to trap and absorb a wide range of odors and pollutants, including:
- Hydrogen sulfide
- Volatile organic compounds (VOCs)
- Heavy metals
Coffee Biochar Can Make Concrete More Durable
Concrete is a versatile building material that is used in everything from foundations to sidewalks. However, it can be susceptible to damage from things like water and salt. But coffee grounds can also make concrete more durable and resistant to cracking. This is because coffee grounds contain lignin, a natural polymer that binds the concrete together.
In addition to being durable, coffee grounds also make concrete more porous. This means that it can absorb more water, which can help to prevent it from cracking. This makes them a perfect addition to concrete, as they can help to improve its durability.
Studies have shown that coffee grounds can be used to replace up to 20% of the sand in concrete without sacrificing strength or durability.
Coffee Is Microbe Resistant
Coffee grounds also contain caffeine, which has been shown to have antimicrobial properties. According to researchers, coffee extracts have been shown to have strong antibacterial activity against a wide range of bacteria, including pathogens such as Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis.
The antibacterial properties of coffee are due to its chemical compounds, including: Flavonoids, CGA, Caffeic acid, Trigonelline, Caffeine, α-dicarbonyl compounds.
Why do the antimicrobial properties of coffee matter to the concrete industry? This can help to protect concrete from mold and other harmful bacteria that might cause it to breakdown over time.
How Adding Used Coffee Grounds To Concrete Could Revolutionize The Construction Industry
Biochar is a relatively new material, and more research is needed to fully understand its long-term performance in concrete. But as the demand for sustainable building materials continues to grow, biochar is likely to become an increasingly popular option for concrete manufacturers. Not only is it a renewable resource that can help to reduce the environmental impact of concrete production, but it makes concrete stronger. It’s a win-win for everyone.
So, next time you’re brewing a pot of coffee, take a moment to reflect on how valuable your used coffee grounds could be to the concrete industry in the future.
Frank Wilson is a retired teacher with over 30 years of combined experience in the education, small business technology, and real estate business. He now blogs as a hobby and spends most days tinkering with old computers. Wilson is passionate about tech, enjoys fishing, and loves drinking beer.