The amount of waste generated in the construction sector highlights the urgent need to incorporate the circular economy – a sustainable model that aims to minimize waste and maximize material efficiency through recovery and reuse – in the built environment: 600 million tonnes of construction and demolition waste were produced In the United States alone in 2018, with 820 million tons reported in the European Union and over 2 billion tons per year in China.
This significant loss of resources in our current industrial ecosystem marks a linear economy that operates on the “take-make-dispose” design model; In contrast, the make-use-reuse approach of a circular economy offers an important opportunity to reduce environmental impact.
A team of MIT researchers has begun assessing what may be needed to drive widespread circular transition in the built environment in a new open access study. The aim is to understand stakeholders’ current perceptions of circularity and quantify their willingness to pay.
“This paper represents a first attempt to understand what might motivate the industry and how integrating stakeholder motivations might lead to greater adoption,” says lead author Juliana Berglund-Brown, a doctoral candidate in the Department of Architecture at MIT.
Consideration of stakeholder perceptions
Three different stakeholders from North America, Europe, and Asia—material suppliers, design and construction teams, and real estate developers—were surveyed by the research team, which included Akrisht Pandey '23; Fabio Duarte, deputy director of the MIT Senseable City Lab; Raquel Ganitsky, fellow in the Sustainable Real Estate Development Action Program; Randolph Kirchain, co-director of the MIT Concrete Sustainability Hub; and Siqi Zheng, STL Champion Professor of Urban and Real Estate Sustainability in the Department of Urban Studies and Planning.
Despite growing awareness of reuse practices among stakeholders in the construction industry, circular practices have yet to be implemented at scale – due to many factors affecting the interface between construction requirements, government regulations and the economic interests of real estate developers.
The study finds that perceived barriers to circular economy adoption vary by industry role, with the lack of both customer interest and standardized structural assessment methodologies identified as a key concern for design and construction teams, while the biggest deterrent for materials suppliers is logistics complexity and supplies are uncertain. For real estate developers, on the other hand, it is primarily about higher costs and a structural assessment.
Encouragingly, however, respondents expressed a willingness to bear higher costs, with developers reporting they would pay an average of 9.6 percent higher construction costs for a reduction in carbon emissions of at least 52.9 percent – and all stakeholders strongly support the potential of incentives such as tax exemptions to promote cost premiums.
Next steps to promote circularity
The results highlight the need for further conversations between design teams and developers, as well as further exploration of possible solutions to practical challenges. “The special thing about circularity is that there are opportunities for great value creation and therefore profits,” says Berglund-Brown. “If people are motivated by cost, we should create a cost incentive or develop policies that provide one.”
When it comes to motivations for adopting circularity practices, the study also found trends that emerged depending on industry role. Future net zero targets influence both developers and design and construction teams, with government regulation being the third most cited reason across all respondent types.
“The construction industry needs a market driver to embrace circularity,” says Berglund-Brown. “Whether carrot or stick, stakeholders need incentives for adoption.”
The impact of policies to promote change cannot be overstated, as great progress has been made in designing low carbon buildings following the introduction of emission control policies such as: E.g., Local Law 97 in New York City and the Building Emissions Reduction and Disclosure Ordinance in Boston. These policy measures and their results can serve as models for concrete CO2 reduction policies elsewhere.
Berglund-Brown suggests that municipalities could adopt ordinances requiring the dismantling of buildings, which would allow the reuse of components and curb demolition methods that result in waste rather than salvage. Top-down regulations could be a way to trigger a supply chain shift towards remanufacturing of construction materials that are typically considered “end-of-life.”
The study also identifies other challenges to implementing circularity at scale, including risks associated with reusing materials in new buildings and disrupting status quo design practices.
“Our work is to understand how we can best motivate the transition despite uncertainty,” says Berglund-Brown. “In addition, researchers can continue to do much to mitigate risks, such as developing standards for reuse.”
Innovations that challenge the status quo
It's not unusual for MIT researchers to disrupt the status quo; Other visionary work in the field of circular economy in construction developed at MIT includes “a smart parts set” called Pixelframe. This modular concrete reuse system allows for multiple dismantling and rebuilding of building elements, facilitating dismantling and reuse while maintaining material efficiency and versatility.
Developed by the research team of MIT Climate and Sustainability Consortium Deputy Director Caitlin Mueller, Pixelframe is designed for a wide range of applications, from residential buildings to warehouses. Each piece of interlocking precast concrete modules, called pixels, is assigned a material passport to enable tracking of many life cycles.
Mueller's work shows that circularity can work technically and logistically at the level of the built environment – specifically designed for disassembly, configuration, versatility, and carbon and cost efficiency in advance.
“This can be built today. “This complies with building codes today,” Pixelframe’s Mueller said in a keynote address at the recent MCSC Annual Symposium, which brought together industry representatives and members of the MIT community to discuss scalable solutions to climate and sustainability challenges. “We currently have the potential for effective CO2 reduction as a compelling alternative to the usual construction methods we are used to.”
Pixelframe recently received a grant from the Massachusetts Clean Energy Center (MassCEC) for further commercialization, an important next step toward practical integration of such innovations into a circular economy. “It is MassCEC’s mission to ensure these climate leaders have the resources they need to transform their technologies into successful companies that make a difference around the world,” MassCEC CEO Emily Reichart said in a press release.
Thanks to a historic climate law from the Biden administration, additional support for circular innovation has emerged. The Environmental Protection Agency recently awarded a federal grant on promoting steel reuse to Berglund-Brown—whose doctoral thesis focuses on scaling the reuse of heavy-gauge structural steel—and John Ochsendorf, a 1942 professor of civil and environmental engineering and architecture at MIT.
“There is a lot of exciting upcoming work on this topic,” says Berglund-Brown. “To any practitioners reading this who are interested in getting involved – please get in touch.”
The study is supported in part by the MIT Climate and Sustainability Consortium.