Project Team

  • Architect: École d’ingénieurs
  • Structural Engineer: Bétons, the Communauté d’Agglomération des 2 Baies en

Using seashells to cut carbon and reuse local waste

Each year the UK seafood industry generates up to 30,000 tonnes of waste scallop, cockle and whelk shells which often end up in landfill or are left to accumulate outside of processing plants. 

Thanks to an Anglo-French partnership, a project on the Lancashire coastline has found an ingenious way to reuse waste seashells as aggregate in concrete surfaces. 

“We can use shells to replace up to 20% of the aggregate in concrete,” explains Professor Karl Williams, director of the Centre for Waste and Resource Management at the University of Central Lancashire (UCLan). “Shells are basically calcium carbonate and, when crushed and put into a concrete mix, they behave much like limestone,” adds Williams.

Using seashells from nearby Fleetwood, UCLan successfully laid a 50m2 trial area of permeable shell-concrete in a community garden in Blackpool, working with local arts organisation LeftCoast.

The mix was specially designed to produce a low-load surface, suitable for footpaths, cycle paths and car parks – places where its permeable nature can reduce the risk of puddles and flooding without

expensive drainage systems.

French researchers at the BUILDERS École d’ingénieurs originally looked at using seashells to make permeable concrete paving slabs.

The next step for the team in Lancashire is to optimise the crushing to reduce waste, and also to continue looking at how different shell combinations perform.

As well as helping to minimise waste, shell-mixed concrete can also deliver carbon saving benefits by reducing the need for aggregate extraction and the transport emissions to landfill.  

Whether it’s on the coastline or in urban areas, finding new uses for waste products and reducing the need to extract raw aggregate materials is an important part of the journey to net zero.