Repurposed seashells create eco-friendly cement

A design studio has developed a sustainable material made from seashell waste, offering a more energy efficient alternative to cement

Spotted: Every year, it is estimated that more than 7 million tons of seashells are thrown away by the seafood industry. The shells are not biodegradable, are expensive to dispose of, and can harm the environment. However, seashells are also made largely of the mineral calcium carbonate, which just happens to be a major constituent of cement – a major polluter. A design studio based in Seoul and London has developed a way to kill two things with one stone by using waste seashells as a concrete substitute. 

Newtab-22 is a design studio that specialises in natural, new and overlooked materials. Their material, named “Sea Stone”, is made by grinding down seashells and combining them with natural, non-toxic binders. The mixture is placed in a mould and left to solidify into tiles. The result is a sustainable cement alternative that retains the variations in textures and colour from the original seashells. Different textures and colours can be created by adding different shells, binders and natural dyes. 

While Sea Stone has similar properties to concrete, it is not as strong, as it has made without the use of an energy-intensive heating process. As a result, Newtab-22 uses the material to create small, decorative items such as incense holders and tabletops. However, the material could be made durable enough for building purposes, although at the sacrifice of some of its sustainability. 

Newtab-22 explains that discarded seashells represent a very real environmental issue. “Even though some seashells [are] recycled and used as fertilisers, the majority of them are being thrown into landfills or by the seaside. The discarded seashells, which are uncleaned or rotten, have not been cleared away at all and they have been piling up near the beach for a long time, thus causing odour pollution and polluting the surrounding land in the long run.” 

Cement is ubiquitous, but it is also hugely energy-intensive to produce. This is why we are seeing growing interest in finding more sustainable substitutes. Some recent innovations in the search for cement substitutes include an eco-friendly bio-cement and concrete injected with CO2, to offset the carbon produced in manufacturing. 

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