A team of researchers from the University of East London, UK, developed a sustainable alternative to cement using shoreline waste, according to a study published in Construction Materials.
The team found that discarded seashells — typically treated as waste —can be used to make a low-carbon concrete ingredient. This cuts significant CO₂ emissions from one of the world’s most polluting materials and helps drive more sustainable construction.
Cement is responsible for around 7% of global carbon emissions. By grinding discarded scallop shells into fine powder and substituting them for part of the cement mix, the team achieved 36% carbon reductions while keeping most of the concrete’s core performance features intact. The study demonstrates that powdered shells can act as both a filler and a partial cement substitute.
“Concrete is everywhere, and consequently, its carbon footprint is enormous. What we’ve shown is that something as ordinary as discarded shells can make a meaningful dent in those emissions. At moderate replacement levels, the concrete behaves very well, which means this could be scaled up in real-world settings,” said Dr Ali Abass, Associate Professor at UEL.
The team conducted a structural analysis, which revealed that calcium-rich shells refine the concrete’s pore structure and support the formation of additional binding compounds, offering further performance benefits.
“Millions of tonnes of shell waste are produced globally each year, and most of it has no useful destination,” Dr Abass added. “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.”
The authors suggest that the potential for adoption across the construction sector is considerable, particularly as tighter environmental standards become more prevalent. As the pressure grows to decarbonise supply chains, the use of naturally derived waste materials could offer an accessible route to measurable reductions.
As Dr Abass added, “A future where yesterday’s coastal by-product becomes tomorrow’s structural backbone isn’t far-fetched – it’s practical, cost-effective, and increasingly necessary.”
Abbas, A.; Kudukkan, A. Experimental Investigation of Low Carbon Concrete Using Ground Seashell Powder as Filler and Partial Cement Replacement. Constr. Mater. 2025, 5, 82. https://doi.org/10.3390/constrmater5040082