A team from the University of East London has demonstrated that it is possible to replace up to 33% of the cement in concrete with crushed seashells, achieving a 36% reduction in carbon emissions.
The finding, published in the journal Construction Materials, surprises even those who have been following the evolution of sustainable construction materials for years.
The weight of cement in the climate crisis
Cement remains responsible for nearly 7% of global CO₂ emissions, a figure that reflects the sector’s difficulty in reducing its impact at the pace demanded by science. Therefore, any viable alternative that decreases its environmental footprint receives great attention.
The British study confirms that crushed scallop shells in fine powder can replace part of the cement and act as a filler. The mixture maintains its strength within the margins required by the industry and, in some cases, even improves the internal structure of the material thanks to the high calcium carbonate content.
A simple idea with great potential
The project leader, Dr. Ali Abass, puts it directly:
“Something as common as coastal waste can alleviate a considerable part of the problem.”
The proposal is so simple that it’s hard to believe it has been overlooked for years. It involves taking advantage of an abundant and low-value resource that is currently discarded, integrating it into a sector that consumes more than 4 billion tons of cement per year.
Regulations and circular economy
The demand for materials that support stricter life cycle emissions regulations in buildings and infrastructure continues to grow. Countries like the United Kingdom, the Netherlands, and Denmark already have regulatory frameworks that require measuring and justifying the carbon footprint from extraction to the end of the material’s life.
In this scenario, any mixture that reduces CO₂ without increasing costs becomes attractive. Moreover, the proposal fits with the trend towards the circular economy, where waste from one sector becomes inputs for another.
European ports like Vigo or Brest are already experimenting with marine waste valorization programs, although primarily oriented towards agricultural uses. This study opens a similar path but with a potentially much greater impact.
Validation in real works and favorable logistics
The next step is to validate the material’s behavior in real works. Some European construction companies are already testing alternative mineral additives to reduce the carbon intensity in their mixtures, so this innovation would fit into their development lines.
Logistics also play in favor: marine waste is concentrated in ports and seafood processors, allowing for the creation of close and stable supply chains.
Costs and social benefits
Although the initial processing of the shells requires energy, starting from a very low-value waste keeps the material competitive. It could even benefit coastal communities if local collection and treatment programs are created, generating employment and reducing marine pollution.
Practical ways for implementation
- Integrate these substitutes in public projects with reduced carbon goals, such as schools or social housing.
- Create local incentives for the fishing industries to deliver clean shells ready for processing.
- Combine shell powders with other low-emission additives, like ashes or industrial by-products.
- Develop technical standards that allow certifying mixtures with marine-origin materials.
The use of marine calcareous waste in concrete is not a single solution, but it is a realistic and achievable piece within the set of strategies to reduce the climate crisis. If scaled intelligently, this technology can improve the lifespan of infrastructures, reduce the impact of mining, and prevent tons of coastal waste from being forgotten.
