VALORFIN: New Cementitious Materials from the Valorisation of the Fine Fraction of Construction and Demolition Waste

The transition to a circular economy is essential to reduce the environmental impact of the construction sector, which is responsible for a large volume of waste and around 8% of global CO₂ emissions, mainly due to Portland cement production. Valorising the fine fraction of CDW, which has been underused until now, presents a promising solution for reducing emissions and making use of existing resources.

Currently, CDW recycling focuses primarily on the coarse fraction, i.e. the larger-sized materials. However, the fine fraction mainly consists of cement paste, which contains amorphous calcium silicate hydrates and calcium aluminate hydrates, calcium hydroxide, along with the finer portions of aggregates, brick debris, gypsum, and soil. From these components, it is possible to manufacture binder materials that can partially replace Portland cement. This leads to energy and raw material savings and a considerable reduction in CO₂ emissions.

The VALORFIN project aims to develop a technological solution to reuse this fine fraction of CDW in the production of a new reactive material suitable for manufacturing low-emission blended cements.

To achieve this, experiments will be carried out using waste collected directly from demolition plants, employing binders to precipitate fine components from washing waters. Physical separation methods that do not require chemical agents will also be tested.

Using these fine fractions, the properties of industrial residues will be modified to transform them into Supplementary Cementitious Materials (SCMs), suitable for use in low-carbon blended cements. Additives will be used to adjust formulations, and slag and kaolinitic materials will be incorporated to enhance the properties of the new products.

The main expected outcomes of the project include:

• Obtaining and characterising secondary raw materials: construction and demolition waste mixed with slags or kaolin.
• Optimisation of separation and activation processes.
  
• Formulating waste combinations and optimising thermal and mechanical activation processes to produce active materials with binding properties.
• Studying the behaviour of pastes and mortars with blended binders in both fresh and hardened states.
• Assessing the potential release of contaminants from the final materials and conducting life cycle analysis.
  
  

Impact

The VALORFIN project could have a significant environmental impact. With a 30% replacement of Portland cement, up to 451,000 tonnes of CO₂ could be avoided annually, effectively contributing to climate change mitigation. In more ambitious scenarios, with replacement levels up to 76%, emission reductions could exceed 1.1 million tonnes of CO₂ per year. In addition to reducing pressure on natural resources such as limestone, this would help meet the construction sector’s decarbonisation and circular economy targets.

The project is also aligned with the “Climate change adaptation, including societal transformation” objective under the European Commission’s Horizon Europe programme, within the framework of the EU Missions.

Budget and Funding

The project is part of the Spanish national Plan for Scientific and Technical Research and Innovation 2021–2023 (PID2022-1415140B-I00), funded with a budget of € 87,500. It will run for four years (September 2023 – August 2027).