CARTIF is taking part in this Horizon Europe initiative, which will develop one of its full-scale demonstration sites in Valladolid to transform textile waste and biomass ash into materials for the construction sector.
The European HUBS4BUILD project is launching this September with the aim of turning one of cities’ greatest challenges—their waste—into new resources for construction and urban development. CARTIF is part of the international consortium behind the initiative, which over the next four years will create a network of Circularity Hubs, or regional circularity centres, across Europe.
Its purpose is to connect sectors that traditionally operate separately, including raw material producers and waste managers, manufacturers, architects, public authorities and construction companies. The goal is to develop new value chains in which resources available within each region can be brought back into the economy.
The project addresses a major challenge for the construction sector. The built environment accounts for approximately 40% of the European Union’s energy consumption and 36% of its greenhouse gas emissions, while many circular alternatives still face technical, economic and regulatory barriers that hinder their large-scale deployment.
HUBS4BUILD aims to help overcome these barriers by demonstrating new solutions and collaborative models under real-world conditions. The project will develop and validate more than nine construction products based on bio-based resources or secondary materials and deploy the solutions in 13 European environments. Overall, it plans to recover more than 700 tonnes of local waste and train over 200 professionals.
Valladolid as an urban circular economy laboratory
One of these demonstration environments will be located in Valladolid, where the Provincial Waste Treatment Centre (CTR) will become the core of an urban biorefinery model designed to transform currently underused waste streams into new resources. The aim is to achieve a reduction of more than 30% in the embodied CO₂ of the new materials developed and create a model that can subsequently be replicated in other regions.
The demonstration will focus mainly on two types of waste. Municipal textile waste will be used to develop insulation materials for construction. Biomass ash from the city’s district heating network, currently managed as waste, will also be recovered and used as a binder for applications such as soil stabilisation and pavement base layers. The solutions developed will then be implemented at full scale.
In this way, Valladolid will make it possible to study the entire value chain: from the availability and characteristics of locally generated waste to its transformation, incorporation into a new material and application in a real-world environment.
The Valladolid demonstrator will also be supported by work addressing costs, usability, risks, circular public procurement and new business models, helping to ensure the viability of the solution. Initial estimates also point to the potential creation of between four and six skilled jobs linked to the new model.
In addition to Spain, the other main operational centres will be located in Greece, the Netherlands and Romania. A total of 13 regional hubs will be established. One of the project’s distinctive features is its ambition to address circularity beyond the development of a single material, analysing how these solutions can become permanently integrated into the economy of each region.
Bringing circularity from the laboratory to the city
CARTIF’s participation in HUBS4BUILD is closely linked to several research lines the technology centre has been developing for years in the fields of circular economy, waste valorisation and the decarbonisation of the construction sector.
The centre works on developing and validating solutions capable of reducing the use of virgin raw materials, reusing materials and waste, and assessing circularity throughout the life cycle of buildings and products. CARTIF also has experimental and material and process characterisation capabilities that make it possible to progress from technological development to validation under conditions close to those found in industry.
HUBS4BUILD will run until August 2030 and is coordinated by the University of Thessaly. The project aims to ensure that its operational centres continue beyond the end of European funding, functioning as regional structures capable of connecting resources, knowledge, industry and public authorities over the long term.