Using recycled plastic in the building industry : Sustainable construction: From niche to norm

The construction industry has, for the longest time, not exactly been a pinnacle of sustainability. But this is changing. And not only in the obvious ways by using renewable materials or reusing building materials such as tiles and wood panelling. More and more, the industry is incorporating recycling as a tool to increase sustainability: Crushed concrete makes sturdy road bases and drainage systems, cutting out the need for fresh materials and lowering carbon emissions. Reclaimed wood finds a new purpose in flooring, furniture and even structural elements, while untreated wood can be turned into mulch or biomass fuel. Metals like steel, aluminium and copper can be endlessly recycled without losing strength, reducing the need for mining. Bricks and masonry can be reused in construction or crushed for landscaping. Even asphalt gets a second life in new pavements, and plastics can be transformed into piping, insulation or composite materials.

It is high time the construction industry reduced its environmental impact. According to a study published in MDPI's Sustainability journal last year, the construction industry is responsible for approximately 30–40% of global solid waste production. Similarly, the European Commission reports that construction and demolition waste accounts for more than a third of all waste generated in the EU.
Construction waste isn’t just an eyesore ‒ it’s an environmental and economic burden. Landfills are filling up fast, with construction debris making up nearly 60% of landfill waste in places like the UK. Extracting new materials depletes natural resources and destroys ecosystems, while hazardous waste can pollute soil and water. Meanwhile, greenhouse gas emissions from material production and landfill decomposition contribute to climate change.
The economic toll is just as significant. Disposal costs add up, while valuable recyclables like metals and concrete go to waste. Poor waste management also creates health risks, from airborne dust to toxic materials, and companies failing to comply with stricter regulations face fines and reputational damage.

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During her speech at the opening plenary of the second meeting of the intergovernmental negotiating committee on plastic pollution (INC-2) in Paris in 2023, Inger Andersen, Under-Secretary-General of the United Nations and Executive Director of the United Nations Environment Programme (UNEP) warned: “We cannot recycle our way out of this mess.” Which, of course, is true. “Only a determined elimination of unnecessary plastic, a full redesign of the products that we envelop in plastic and a full market transformation that drastically reduces the flow of virgin plastics can do that,” she continued. 
But what is also true is that we simply must recycle as much plastic as we can. To keep the material in the loop as long as possible and therefore reduce the need for virgin materials. A very interesting aspect is using recycled plastic in construction materials. 

Recycled plastic in construction started making waves in the late 20th century, but it wasn’t until the 21st century that it really took off. In the 1970s, early experiments mixed plastic waste with asphalt for roads, while the 1980s-90s saw the rise of plastic lumber as a wood alternative. By the 2000s, India pioneered plastic-mixed roads, and plastic bricks and modular homes gained traction. The 2010s brought plastic-reinforced concrete and more widespread adoption. Now, in the 2020s, recycled plastic is everywhere ‒ from insulation to 3D-printed houses ‒ driven by stricter environmental policies and innovative technology.
Even though recycled plastic in construction is gaining momentum worldwide, each region approaches it differently. The EU leads with strong regulations, pushing for plastic roads, cladding and insulation through policies like the Green Deal. Canada is making slow but steady progress, particularly in road construction, but faces challenges with harsh climates and regulatory gaps. India is now a global leader in plastic roads, with over 100,000 km built, and is exploring plastic bricks for affordable housing. The US is seeing rapid innovation driven by start-ups using recycled plastic for 3D-printed homes and modular blocks, though federal mandates are lacking. As technology improves and governments push sustainability, plastic-based materials are set to play a bigger role in construction globally.

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One of the people heavily invested in advancing sustainable waste management through the reuse of recycled plastic is Dr Sahadat Hossain. He is Professor of Civil Engineering at the University of Texas at Arlington as well as the Director of the Solid Waste Institute for Sustainability (SWIS) there. 
China’s 2018 ban on plastic waste imports triggered the well-known global recycling crisis since way too many countries had not created a local market for reusing recycled plastic waste. And although this resulted in recycled plastic being either sent back to landfills or mismanaged through open burning, innovative minds like Dr Hossain have come up with new ideas on how to deal with all the waste plastic. “Leveraging recycled plastic for transportation infrastructure emerged as a transformative solution,” he recalls. “By incorporating recycled plastic into pavement construction, we not only address the plastic waste crisis but also enhance the longevity of roads. This innovative approach not only establishes a local market for recycled plastics but also fosters a circular economy, promoting sustainability at its core.” 

But it was a long and bumpy road to get to the perfect result. “Achieving the desired mechanical properties without compromising durability involved extensive laboratory testing to identify the plastic grade and proportion of recycled plastics. Adjustments in temperature and mixing time were crucial during the mixing process due to varying melting points and bitumen compatibility, ensuring a homogeneous blend,” the scientist explains. 
After much research and testing Dr Hossain and his team found Low-Density Polyethylene (LDPE) (including single-use plastic bags), High-Density Polyethylene (HDPE), and Polypropylene (PP) to be most suitable for plastic roads. “Interestingly, single-use plastic bags are considered non-recyclable and we used them for plastic road construction,” he explains. 
Up to 10% recycled plastic is incorporated in the so-called plastic roads. Extensive testing showed that plastic roads are more resistant to cracks and potholes, reducing damage by up to 75% and potentially extending their lifespan significantly. “Plastic roads are more durable, less expensive and better for the environment than traditional asphalt roads,” Dr Hossain argues. He can refute the concern regarding the release of microplastics. “Based on our research on samples collected at the laboratory and from the field, microplastic release from plastic roads is not significant and is below the threshold risk characterisation ratio.

So far, the team has built a test road at the university campus in Texas, which is under evaluation for the last 20 months, as well as roads in two districts in Bangladesh. They have performed very well indeed. Last year, during Bangladesh’s hottest summer in 50 years, traditional roads began to soften and melt due to the extreme heat. Dr Hossain’s plastic roads had no visible distress and showed heat resilience.
Like traditional asphalt, plastic-modified asphalt can be milled and reused in new road construction projects as reclaimed asphalt pavement (RAP).

The pavement industry is increasingly open to the idea of plastic roads, Dr Hossain says: “With growing pressure to reduce carbon footprints and manage plastic waste, industry stakeholders such as government agencies, private contractors and transportation departments are more willing to adopt innovative technologies that align with green infrastructure goals.”
There is, of course, a but: The widespread adoption of plastic roads faces significant hurdles, primarily the absence of clear construction guidelines and regulatory backing. Without standardised rules on plastic content, mixing methods and performance benchmarks, gaining acceptance from government agencies and private industries remains a challenge. Equally crucial is the need to train asphalt plant workers, ensuring they can effectively integrate this innovative approach into road construction.
Nevertheless, the World Bank also is aware of the advantages of the plastic roads and their capability to create green jobs and promote a circular economy in developing countries. There are talks about pilot projects in several South Asian countries. 

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Another notable field is the use of recycled plastic pins (RPP) as an alternative to traditional soil and slope stabilisation methods. These pins, made from recycled plastic waste, help to reduce waste and promote a circular economy by reusing materials that would otherwise end up in landfills or oceans. “They are known for being lightweight, durable and corrosion-resistant, making them ideal for use in geotechnical engineering construction,” Dr Hossain elaborates. “Because of their ability to withstand harsh environmental conditions without degrading and excellent load-bearing capabilities, RPPs are being widely used in construction for soil and slope stabilisation in Texas.”
But it does not stop there: Plastic bricks and paving stones, known for their low weight, weather resistance and durability, are particularly suited for footpaths, driveways and affordable housing projects. Plastic lumber provides an eco-friendly alternative to wood for fencing, decking and park benches, requiring minimal maintenance while resisting rot. In drainage and piping systems, recycled plastics are used to manufacture corrosion-resistant corrugated pipes that outlast traditional materials. Even railway infrastructure benefits, as plastic sleepers offer a more durable, termite-resistant and low-maintenance alternative to wood or concrete. Additionally, plastic’s lightweight and noise-reducing properties make it an effective material for highway sound barriers, further showcasing its versatility in modern construction.

For another interesting application for recycled plastic, you need to look up. Just like asphalt roads, classic asphalt roofing can be improved by adding recycled plastic, giving it the double benefit of reducing plastic waste and thus contributing to a circular economy.
Canadian company Green Mantra has developed a special polymer additive sourced from polypropylene and polyethylene recycled materials from across North America ‒ streams of waste plastic that are typically more difficult to recycle by traditional mechanical recycling, such as various types of packaging materials. “Our molecular recycling process transforms waste plastics into high-performance specialist polymers and additives. Unlike traditional mechanical recycling, which melts and reshapes plastic, our process breaks down plastic at a molecular level into new, functional materials,” explains Green Mantra’s CEO Domenic Di Mondo. 
Having undergone extensive laboratory testing and field trials to ensure they meet the highest performance standards for asphalt shingles and roads (the additive can be used for both), Di Mondo is confident that their product enhances the performance and longevity of essential infrastructure. “CERANOVUS polymer additives enhance durability, flexibility and overall performance in both roofing and asphalt applications. In roofing materials, these additives improve asphalt shingles by increasing resistance to weathering and mechanical stress at elevated temperatures, helping extend their lifespan and reducing maintenance needs,” he argues. “And they make it easier for manufacturers to add recycled materials into their product designs.”
And, as he points out, the asphalt shingles remain fully recyclable. “This supports a more circular approach in the roofing industry, enabling the repurposing of recycled shingles into new roofing products or asphalt paving applications,” Di Mondo stresses.
 

According to Di Mondo, the industry has embraced advanced formulations and technologies that enhance material properties while incorporating recycled content, but this naturally requires rigorous testing and validation. In paving, recycled asphalt pavement (RAP) and recycled asphalt shingles (RAS) are widely used, with DOT regulations ensuring performance comparable to virgin materials. Studies confirm that RAP and RAS improve road durability while lowering costs. The Federal Highway Administration supports these practices, which reinforces their viability. 
“The roofing industry is increasingly embracing recycled materials as sustainability becomes a greater priority. Shingle manufacturers are innovating with recycled rubber and plastics in roofing membranes and shingles, with extensive testing helping to validate long-term performance,” says Di Mondo. “Green building incentives and growing industry confidence are further accelerating adoption. As advancements continue, the use of recycled materials in both roofing and paving is expected to expand, supporting a more sustainable future without compromising durability or safety.”

Expanding recycled materials in roofing and paving comes with challenges, from material consistency to regulatory roadblocks. Variations in recycled asphalt, shingles and plastics can affect durability, while inconsistent policies often favour virgin materials. Limited recycling infrastructure adds costs, and some contractors remain sceptical, prioritising reliability over newer alternatives. Still, sustainability goals and cost savings are pushing progress. Overcoming these hurdles will take better processing, standardised regulations and solid performance data to build industry confidence, Di Mondo argues. 
 
He also advocates for intense collaboration among manufacturers, regulators and industry stakeholders. “Manufacturers can invest in innovation and testing to develop high-performance materials incorporating recycled content while maintaining durability and safety standards. Regulators can support adoption by establishing clear guidelines, incentives and certifications that encourage sustainable practices without adding unnecessary barriers. Industry stakeholders, including contractors and specifiers, can advocate for and adopt proven sustainable solutions, ensuring demand for greener materials continues to grow.
“By working together, the industry can expand recycling infrastructure, standardise material specifications and drive policy changes that support circular economy practices.”

While progress in the adoption of recycled materials in construction is undeniable, there's still a long way to go. Scaling up these innovations requires overcoming infrastructure gaps, regulatory inconsistencies and lingering scepticism within the industry. However, the momentum is growing. As technology advances and policies evolve, the integration of recycled plastics will become more seamless. The construction industry has a unique opportunity to transform itself from a major waste producer to a leader in circular economy solutions. With continued collaboration, investment and commitment, sustainable construction can move from a niche to the norm.