Building cities from cities: driving circularity

Building better with less: our commitment to the circularity of cities

The global economy is currently only 7% circular, a figure that highlights the urgency of accelerating the transition toward models focused on reducing, reusing, and recycling. At Holcim, we understand that building a circular economy is a challenge that requires the collaboration of all actors across the value chain. Under the principle of building better with less, we extend decarbonization and circularity in construction materials throughout our daily work.

The world builds the equivalent of a city like Madrid every week, in response to global population growth, urbanization, and the desire to improve quality of life. Each year, more than 40 billion tons of raw materials are extracted to build our homes, schools, hospitals, roads, and other vital infrastructure. Achieving more circular construction is essential to respecting the limits of our planet while improving quality of life for everyone.

Our strategy goes beyond the opportunities to apply circularity in the construction phase. We also consider the opportunities to apply it when buildings reach the end of their useful life, as construction and demolition materials (CDM) represent an important resource stream. In Europe alone, CDM account for one third of the total volume of waste. With sustainability—and thus circularity—as a driver of profitable growth, Holcim operates more than 150 recycling centers worldwide.

We promote the circular economy across all areas of our operation, from our plants and products to the built environment. We rigorously follow the three key principles of this model: reducing the consumption of natural resources, reusing materials whenever possible, and recycling what previously was considered waste.

In this regard, concrete is infinitely recyclable. We are expanding our capacity to recycle demolition materials made of concrete as substitutes for natural aggregates and low-emission raw materials for our sustainable building solutions. To achieve this, we develop proprietary technologies such as ECOCycle®, breakthrough innovations, and smart recycling centers. Our goal is to drive transformation and evolve construction standards, promoting mandatory recycling in construction.

Under this approach, Holcim has participated in the European BLADES2BUILD project, a standout example of cross-sector cooperation to work together with the aim of giving a second life to materials previously considered non-recyclable, such as wind turbine blades, which in Europe are considered CDM. Holcim’s role in the project focuses on scaling circular construction solutions.

Transforming a complex waste into a circular, low-carbon concrete

The innovation behind BLADES2BUILD has enabled us to reuse complex waste and reduce the use of natural raw materials. This is especially relevant in the construction sector, which has traditionally depended heavily on natural resources.

At Holcim, we have put innovation at the service of construction. The process for developing this circular concrete begins with the crushing and treatment of wind turbine blades at the end of their useful life, using specialized technology carried out by companies within the consortium. These materials are then incorporated into concrete production as a partial substitute for natural aggregates.

This new composition for circular concrete was led, in its first stage, by the Holcim Innovation Center (Lyon, France), where studies were conducted on the rheological performance and durability of concrete containing wind turbine blade waste. Later, at the Holcim Spain Central Concrete Quality Laboratory (Alcobendas, Madrid), a pioneering formulation was developed that incorporates these crushed blade materials as a partial replacement for natural aggregates.

This new concrete formulation offers a real solution for the management of millions of tons of waste generated through the renewal of renewable energy parks, contributing to closing the life cycle and enabling circular construction from beginning to end.

A real example of building the new from the old: Aldeavieja wind farm

The first supply of concrete incorporating fibres resulting from the crushing of wind turbine blades has been delivered from our Majadahonda concrete plant to Endesa’s Aldeavieja (Ávila) wind farm.

The key features of this concrete supply have been:

• Use of ECOPact concrete: providing significant advantages in terms of CO₂ emission reduction thanks to the use of ECOPlanet low-carbon cement.
• Incorporation of more than 10% recycled material: recycled aggregate and crushed wind turbine blade material, allowing this solution to be classified within the ECOCycle® recycling technology framework.
• Compliance with technical requirements: meeting all required mechanical, rheological and durability specifications.

As a first project, Aldeavieja is more than a proof of concept: it is a scalable prototype for the future of renewable energy infrastructure and our cities. It is also a testament to the power of cross-sector collaboration to drive sustainable construction.

Driving circularity

As part of Holcim’s NextGen Growth strategy, our goal is to recycle more than 20 million tons of construction and demolition materials by 2030. Our participation in BLADES2BUILD will contribute to this ambitious objective, not only for concrete but also for other applications.

In addition to demonstrating the technical and economic viability of this solution for the treatment of wind turbine blades, BLADES2BUILD will showcase its scalability with a 6,000 m² treatment plant currently under construction in Castile and León.

Collaboration, such as the one we have established with Endesa, is essential to unlocking the potential of decarbonization and circularity in the future of the sustainable construction of our cities and essential infrastructure.