Growing evidence of anthropogenic climate change has forced industries to work to reduce their greenhouse gas emissions. Several strategies have been explored recently in the construction industry, including increased use of renewable energy, green manufacturing processes, and green building materials.
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The rapid increase in world population and urbanization has resulted in the need for an unprecedented amount of construction materials to construct domestic, commercial and industrial buildings, as well as infrastructure such as roads, tunnels and power stations. Concrete, steel and glass are ubiquitous building materials in the modern era, but their manufacture uses large amounts of raw materials and water and emits large amounts of greenhouse gases per year.
Cement manufacturing alone produces 622 kg of carbon dioxide per tonne of cement produced, with approximately four billion tonnes of cement produced each year. 8% of total global carbon dioxide emissions come from cement manufacturing alone. Additionally, embodied carbon, i.e. the carbon released throughout a building’s life cycle, including the disposal of end-of-life materials, is responsible for 11% of total global emissions. of carbon. The impact of these “hidden” emissions is vast.
Several conventional and innovative green building materials are increasingly being explored to reduce the impact on the construction industry. Here are some traditional and cutting-edge green building materials that are helping to improve sustainability in the construction industry and reduce its carbon footprint.
Wood has been used for millennia as a building material. Using reclaimed wood utilizes waste streams and can easily come from construction sites, retired barns, pallets and salvage yards. This material saves virgin resources and reduces landfill usage. Reclaimed wood is useful for framing, flooring, and cabinetry. Reclaimed wood is lightweight but has drawbacks including reduced strength and the need for processing and reinforcement.
Bamboo is an incredibly fast growing and carbon neutral building material. This perennial grass grows in many parts of the world and continues to proliferate without the need for replanting. Bamboo has a high strength to weight ratio, is durable and has greater compressive strength than concrete or brick. Useful for flooring and cabinetry, a downside is the need for treatment to prevent rot, water absorption and insect infestation.
Another ancient material, clay, is a long-lasting green material. It has advantages for use in foundations, floors, walls and can be pressed into wooden frames to produce a building material similar to concrete. Rammed earth walls and floors can be used as natural thermal storage, being warmed by the sun during the day and releasing their heat in the evening when it is cooler.
Rammed earth buildings contain significantly lower amounts of embodied carbon than traditional concrete buildings and can be reinforced by the use of bamboo or rebar.
Recycled plastic can be used for many purposes in construction projects, such as flooring, roofing and windows. The use of plastic waste reduces the environmental impact of the construction industry and the plastics industry, reducing landfill and helping to mitigate greenhouse gas emissions. Recently, several innovative studies have explored the incorporation of polymeric materials into concrete in the form of aggregates, reducing carbon emissions and improving its mechanical and chemical properties.
Recovered and recycled steel
Steel has the benefit of being 100% recyclable, and using reclaimed and recycled steel significantly reduces energy demand and carbon emissions. Possessing sufficient mechanical and physical properties even after reprocessing, recycled and reclaimed steel can be used for framing, roofing, facades and foundations and is an incredibly durable building material.
HempCrete is an innovative green material that uses hemp, a natural and sustainable resource and carbon sink, to construct a concrete-like material. The woody inner fibers of the hemp plant are combined with lime to build renewable, carbon-neutral, strong and lightweight blocks that reduce transport costs and energy. The material is fire resistant and has good sound and thermal insulation properties.
Similar to Hempcrete, Timbercete uses renewable energy and CO2-neutral resources to produce a green concrete type material. Timbercrete uses sawdust, a valuable waste product produced by the construction and woodworking industries, to replace some of the energy-intensive materials used in traditional concrete manufacturing. It can be used to create bricks, blocks and paving slabs.
Mycelium is the root structure of fungi. This natural material uses a valuable waste stream from the agricultural and food industries to create a green, sustainable and low-carbon building material. Composites of mycelium and pasteurized sawdust are strong and lightweight and can be shaped into a multitude of shaped bricks for different building purposes. Able to withstand extreme temperatures, mycelium-based composites can be used as green insulation and as alternatives to fire-resistant concrete.
Another innovative green building material, Ferrock is a relatively new addition to the construction industry’s sustainable toolkit. Industrial wastes such as ferrous rock and steel dust, which would otherwise be sent to landfills, are used to make a concrete-like building material with superior strength.
During the drying and curing process during production, carbon dioxide is trapped and absorbed, making the material carbon neutral. This innovative green material can be mixed and poured like traditional concrete to produce structures, walkways, flooring and building elements like stairs. Research has indicated that Ferrock is extremely weather resistant, making it a hard-wearing building material.
With the environmental impact of the construction industry becoming clearer, the trend towards net zero in the sector is accelerating. Green building materials are becoming a hot topic in the construction industry and offer an innovative, cutting-edge solution to reducing the industry’s carbon footprint while providing new materials that perform as well or better than existing materials. traditional construction.
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References and further reading
International Code Council (2022) Embodied Carbon in Buildings and Building Materials [online] www.iccsafe.org. Available at: https://www.iccsafe.org/advocacy/embodied-carbon/
Kukreja, R (2022) 15 Sustainable and ecological building materials [online] conserve-energy-future.com. Available at: https://www.conserve-energy-future.com/sustainable-construction-materials.php
Clark, T (2021) Cement: how to reduce your carbon impact [online] constructionnews.co.uk. Available at: https://www.constructionnews.co.uk/sustainability/carbon-cementing-net-zero-22-11-2021/