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The work, carried out by the University of East London (UEL), found that discarded seashells can be transformed into a low-carbon concrete ingredient, potentially cutting significant amounts of carbon emissions from the production of one of the world’s most polluting materials and helping to drive more sustainable construction.
“Millions of tonnes of shell waste are produced globally each year, and most of it has no useful destination,” said lead researcher Dr Ali Abass, associate professor of structural engineering. “If we can divert even a fraction of that into low-carbon construction materials, the environmental gains could be significant. It’s a simple idea with real potential to reshape part of the sector.”
Cement is responsible for about 7% of global carbon emissions. “Concrete is everywhere, and consequently its carbon footprint is enormous,” said Abass.
Shells can act as both a filler and a partial cement substitute once processed into two fine powder grades, the study showed. By substituting finely ground scallop shells into a cement mix, the team achieved carbon reductions of up to 36% while keeping most of the concrete’s core performance features intact.
Microstructural analysis revealed that the calcium-rich shells helped refine the pore structure of the concrete and supported the formation of additional binding compounds.
“The potential for adoption across the construction sector is considerable, particularly as tighter environmental standards and whole-life carbon reporting become more prevalent. With infrastructure and building contractors under growing pressure to decarbonise supply chains, the use of naturally derived waste materials could offer an accessible route to measurable reductions,” a UEL announcement said.
Abass added: “At moderate replacement levels, the concrete behaves very well, which means this could be scaled up in real-world settings… A future where yesterday’s coastal byproduct becomes tomorrow’s structural backbone isn’t far-fetched – it’s practical, cost-effective and increasingly necessary.”
The work was published in Construction Materials.
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