Innovative Use of Seashells in Flood-Resistant Concrete
In the heart of Blackpool, England, The People’s Pantry is not just a community garden but also a fresh food pantry that provides residents of adjacent affordable housing units with an abundance of fresh produce. Recently, the garden has implemented a unique solution to combat frequent water inundation and flooding – a concrete mix made with crushed seashells.
Helen Jones, the operations director at LeftCoast, which oversees the community garden, described the transformation brought about by the seashell concrete. The ground beneath each raised bed of soil is now lined with a smooth sheet of concrete embedded with slivers of ivory shells. As visitors walk on the surface, the shells become more apparent, creating a visually striking and functional barrier against floods.
Previously, the garden experienced regular flooding during rainy days, turning walkways into marshy terrain and causing water to seep into nearby housing units. This prompted Jones to seek a solution, leading to a collaboration with scientists from the University of Central Lancashire. The team developed a permeable concrete mix using discarded shellfish waste from local fish processors, along with traditional concrete materials like cement and aggregate.
Karl Williams, the director of the Centre for Waste Management at the University of Central Lancashire, spearheaded the project. By repurposing shellfish waste into construction material, Williams aimed to minimize the carbon footprint of both the food and construction industries. The pervious concrete made from crushed scallop and whelk shells enhances porosity, allowing water to drain through the surface instead of accumulating.
In addition to its flood-resistant properties, the shell concrete serves as a sustainable solution to the environmental impacts of food waste and traditional construction practices. By diverting waste shells from landfills and incorporating them into building materials, the project contributes to reducing greenhouse gas emissions associated with both industries. Fishmongers also benefit from the initiative, as they can avoid landfill disposal fees by donating their waste shells for repurposing.
Williams emphasized the importance of collaboration between the construction and food sectors to address waste production and carbon emissions. The shell concrete project serves as a bridge between these industries, encouraging them to work together towards a more sustainable future. As coastal and urban areas face increasing challenges from climate change and flooding, innovative solutions like seashell concrete offer a promising way to mitigate environmental impact while enhancing resilience in built environments. Replacing traditional aggregate with alternative materials in construction projects can have a significant impact on reducing emissions generated from quarrying, processing, and transportation. This shift towards using alternative materials is gaining momentum as researchers and engineers explore innovative solutions to make construction more sustainable.
One such alternative material that is being used to replace aggregate in concrete mixes is crushed shells. By incorporating shells into the concrete mix, it is possible to improve porosity, compressive strength, and reduce the amount of traditional aggregate used by up to 20 percent by weight. This not only helps in reducing the carbon footprint of the construction industry but also provides a practical solution to managing waste materials.
While using crushed shells in concrete mixes is not a new concept, the successful implementation of this approach in real-world projects is still relatively rare. Projects like the Blackpool community garden in England and a flood-prone cycling route in northern France have demonstrated the effectiveness of using shell concrete in mitigating flood risks. The positive outcomes of these projects have sparked interest in expanding the use of shell concrete to other sites, such as car parks and sidewalks.
Although crushed shell concrete shows promise in reducing emissions and managing waste, some experts remain cautious about its widespread adoption. Professor Xianming Shi from the University of Miami points out that while using shells in concrete can help reduce emissions associated with food waste, it may not have a significant impact on the overall emissions of the cement industry. Additionally, the use of recycled materials in concrete mixes may not significantly reduce the life-cycle footprint unless these materials are carbon negative.
Despite these challenges, crushed shell concrete is seen as a step towards engaging the public in sustainable construction practices and exploring unconventional materials for building projects. Projects like using living microalgae to produce bio-cement or developing lignin-based resins as alternatives to cement highlight the potential for innovation in the construction industry.
As researchers continue to explore the possibilities of using alternative materials in construction, the focus is on finding localized solutions to address specific challenges, such as flood risk mitigation. By mapping out potential sources of shellfish and understanding the engineering properties of different types of shells, researchers can identify suitable locations for testing shell concrete. Each location presents unique challenges, but the success of projects like the Blackpool community garden demonstrates the potential benefits of using alternative materials in construction.
In a world facing the impacts of climate change, sustainable construction practices like using crushed shells in concrete mixes offer a glimpse into the future of building and construction. As more projects explore the use of alternative materials, the construction industry is poised to embrace innovative solutions that not only reduce emissions but also create resilient and sustainable built environments. The rain garden in the community garden has become a focal point for both environmental enthusiasts and local residents alike. Designed by landscape architect Sarah Jones, the rain garden serves a dual purpose by reducing the need for concrete aggregate and providing a sustainable solution for food waste.
Jones is particularly impressed with the rain garden’s ability to quickly absorb rainwater, even during torrential showers. She notes that unlike traditional pavement or concrete surfaces, the rain garden allows water to be absorbed immediately, preventing any pooling or runoff. This not only helps to reduce the risk of flooding, but also minimizes erosion and pollution in the surrounding area.
In addition to its practical benefits, the rain garden has also become a source of entertainment for visitors to the community garden. Residents have taken to pouring water into the garden, watching as it disappears into the soil. Jones observes that the simple act of interacting with the rain garden has brought joy to the community, with many residents finding delight in the process of water absorption.
Overall, the rain garden has proven to be a valuable addition to the community garden, showcasing the power of sustainable design and environmental stewardship. As visitors continue to marvel at its functionality and residents enjoy the simple pleasure of pouring water into it, the rain garden stands as a symbol of innovation and community engagement.
