How construction innovations are enabling the transition to a circular economy

A just transition to a circular economy is crucial to achieving climate goals. After all, only 55% of emissions can be tackled with renewables and energy efficiency. The remaining 45% must be addressed by changing the way we produce and consume.

The circular economy’s approach to designing, producing and consuming goods eliminates waste and regenerates nature. In short, it ensures we can live within our means and in harmony with the planet.

The building and construction sector offers huge potential for transformational change. The sector’s greenhouse gas (GHG) emissions account for approximately 40% of global GHG emissions – about one-third from the construction phase, and the remaining two-thirds from buildings in use. Furthermore, approximately 50% of the urban environment needed by 2050 is not yet built. Different building techniques, including more circular cement, steel and aluminum, can help ensure we reach net-zero by 2050.

A number of recent innovations from across the globe show what’s possible when businesses, governments and civil society collaborate to move the construction needle from linear to circular.

The innovation: In 2019, a circular viaduct was developed in collaboration between the Netherlands Government and the private sector. Elements of this viaduct were modular and could be disassembled, moved and reused, extending product lifecycles. The viaduct was one of many efforts designed to help halve the country’s use of natural resources by 2030 and achieve a fully circular economy by 2050.

To further maximise the reuse of materials, the Netherlands Department for Public Works together with Rotterdam and Amsterdam, developed a national bruggenbank, or National Bridge Bank. The Bridge Bank is a registry of all (soon-to-be) dismounted bridges and elements thereof. This marketplace for bridges contains information on a bridge’s construction materials and parts available for reuse, and can connect construction companies and municipalities. So far, 13 bridges are registered on the Bridge Bank.

The impact: Modular projects and infrastructure marketplaces are scalable, and are crucial for the development of more circular models in the Netherlands and beyond. These projects demonstrate the vast potential of construction to slash emissions. For instance, in the Netherlands, circular bridges and viaducts can reduce Co2 emissions by up to 63%, and virgin steel consumption by up to 60% simply through the reuse of steel elements.

The innovation: Earlier this year, Holcim launched its global range of green cement. The cement delivers at least a 30% lower carbon footprint compared to ordinary cement. In Switzerland, this includes a version called Susteno that contains 20% recycled construction and demolition waste, ensuring 20% fewer resources drawn from nature. It also delivers a 38% lower carbon footprint.

The impact: The company began offering Susteno once authorities adapted the regulatory requirements to allow it, based on scientific evidence of the material’s performance. This circular cement has been applied in landmark structures such as the soon-to-open HSG Learning Center at the University of St. Gallen, a 7,000 m² work and study facility designed by Sou Fujimoto Architects. Scaling such solutions across global markets could dramatically accelerate the transition to net-zero building.

The innovation: In 2020, the Tobalaba Airport near Santiago de Chile built a new runway using recycled asphalt from an old runway, ensuring that materials did not end up in landfill.

The impact: This led to a 70% decrease in the virgin gravel used, a 74% decrease in waste generation, and a 45% decrease in overall costs. The Ministry of Public Works is already working on expanding these practices to all new airports.

Such projects could have a major impact in Chile. In 2019 and 2020 on average, the public sector in Chile accounted for 55% of all the urban construction in the country. Approximately 18.7% of GHG emissions in Chile are related to manufacturing industries and construction.

These examples show the power of collaboration to drive innovation and systemic change in infrastructure. Scaling future innovation, however, will require looking closely at how construction projects are planned and funded. Public procurement can be an instrument for positive change. Governments, as the largest consumers, can demand more from vendors, and must create incentives for circular and carbon-neutral projects. While countries may be in different stages of developing and implementing green public procurement policies, it is crucial to ensure that socioeconomic and environmental costs drive the circular transition.

Mindset shifts are also critical. Leaders – in business, civil society and government - need to consider material efficiency as addressing the triple planetary crisis, climate, nature and pollution, simultaneously.

Two initiatives are doing just this:

Tackling the challenges in the construction industry, both in terms of building materials used in new construction and improving energy efficiency of buildings in use, will be crucial to reach the goals of the Paris Agreement. By changing the way our supply chains work and stimulating innovative public procurement, we can accelerate innovation, extend product lifecycles and significantly change the way we build for a circular and climate-neutral future.