A groundbreaking discovery by Australian scientists has revealed that incinerated coffee grounds can enhance the structural integrity of concrete by as much as 30 percent.
This ingenious formulation possesses the potential to address several pressing issues concurrently.
Globally, approximately 10 billion kilograms (22 billion pounds) of coffee waste are generated annually, with the vast majority destined for disposal in landfills.
“The management of organic refuse presents a significant environmental hurdle, as it results in the emission of substantial quantities of greenhouse gases, including methane and carbon dioxide, which exacerbate climate change,” articulated Rajeev Roychand, an engineer at RMIT University, when the research was unveiled in 2023.
Concurrently, the burgeoning global construction sector, characterized by a rapidly expanding market, fuels an ever-increasing demand for concrete, a resource-intensive material that brings its own set of ecological challenges.
A synopsis of the investigation can be viewed in the video presented below:
“The persistent extraction of natural sand worldwide – predominantly sourced from riverbeds and adjacent banks – to satisfy the escalating demands of the construction industry, has profound ramifications for the environment,” observed RMIT engineer Jie Li.
“Ensuring a sustainable sand supply chain faces critical and enduring obstacles owing to the finite nature of these resources and the detrimental environmental consequences of sand mining operations. By adopting a circular economy paradigm, we could divert organic waste from landfills and simultaneously bolster the conservation of our natural assets, such as sand.”
Organic materials like coffee grounds cannot be directly incorporated into concrete mixtures as they release chemical compounds that compromise the material’s strength.
To circumvent this, the research team subjected coffee waste to elevated temperatures exceeding 350 °C (approximately 660 °F) under oxygen-deprived conditions, utilizing minimal energy input.
This transformation process, known as pyrolysis, deconstructs the organic molecular structure, yielding a porous, carbon-rich substance termed biochar. This biochar is capable of forming robust bonds, thus integrating effectively within the cementitious matrix.
Roychand and his collaborators also explored pyrolyzing coffee grounds at 500 °C; however, the resultant biochar particles exhibited diminished structural resilience.
The scientists have indicated that further investigation is necessary to ascertain the long-term performance and durability of their novel concrete formulation.
Current efforts are focused on evaluating the hybrid coffee-cement’s behavior under various environmental stressors, including freeze-thaw cycles, water absorption, and abrasive conditions.
Furthermore, the team is actively pursuing the development of biochars derived from a broader spectrum of organic waste materials, encompassing wood, food scraps, and agricultural byproducts.
“While our research is in its nascent phases, these encouraging findings present an innovative pathway to substantially diminish the volume of organic waste directed to landfills,” stated Shannon Kilmartin-Lynch, an engineer at RMIT.
“Drawing inspiration from an Indigenous perspective, my research is guided by principles of Caring for Country – ensuring a sustainable life cycle for all materials and minimizing environmental impact by preventing waste from entering landfills.”
The findings of this research have been formally documented and published in the esteemed publication, the Journal of Cleaner Production.
