Concrete is one of the most popular building materials. However, it is harmful to the environment, mainly due to the carbon dioxide emissions from the production of cement, one of the main components of concrete. Scientists have found a way to make it more environmentally friendly using regular carrots and beets. In addition, root crop waste helps to make electric generators from concrete structures.
After water, concrete is the most widely used substance in the world. The production of cement, a key component of concrete, accounts for about 8% of global CO₂ emissions.
In addition, clinker production requires a high-temperature chemical reaction, which means a lot of energy.
The cement industry is working to decarbonize and reduce fossil fuel emissions. But the chemical part of carbon dioxide emissions is inevitable unless a fundamentally different type of cement is created.
When cement mixes with water, it forms a paste that binds sand and gravel, allowing the concrete to harden and give it strength and structure. Changing this process is one strategy to reduce the environmental impact of cement. Professor Mohamed Saafi of Lancaster University in the UK and his colleagues are working to achieve this goal through the B-SMART project.
The cement must be mixed with water so that it adheres to sand and gravel and binds them together. However, not all cement particles are hydrated during this process. “If we can strengthen this hydration mechanism, its strength will increase significantly, and therefore less cement will be used,” explains Professor Saafi.
By replacing some of the cement with waste, the researchers hope to make the concrete more sustainable.
Professor Saafi and his team turned to root vegetables for help. They studied whether carrot waste processed for baby food or beet sugar extraction residues could be added to cement to strengthen. Using computer simulations, they saw how ultra-thin layers of vegetable waste would interact with cement. Scientists have also studied the effect of vegetables on both cement hydration and its mechanical properties. They then ran experiments in the lab to test the results of their simulations.
Ultimately, the researchers found that using plant waste sheets could improve cement hydration. They acted as reservoirs that allowed the water to reach more of the cement particles and thus improved its binding capacity.
It has also been found that adding root vegetables to cement provides additional benefits. For example, pressing on carrots generates electricity that can power a small LED lamp or electronic devices. When nanosheets of their carrot waste were added to the cement, Professor Saafi and his colleagues discovered that they could make not only sustainable concrete but also generate electricity. If, for example, you build a bridge with this concrete, electricity can be generated by vehicles passing over it or by vibration or movement caused by pedestrians. This concrete electricity can be used to power LEDs or streetlights.