"Advances show that the carbonate materials obtained are sustainable and highly functional"
We validate new waste-based solutions that fix CO₂ and reduce the environmental footprint of cement and concrete
The CIDECAR initiative opens a new avenue to move towards more sustainable construction by developing secondary materials with a negative carbon footprint. In this research, the Eduardo Torroja Institute for Construction Science-CSIC, the Autonomous University of Madrid and TECNALIA have managed to fix up to 172g of CO₂ equivalent per kilo in alkaline industrial and construction and demolition waste.
This development boosts the reduction of the sector's environmental impact and reinforces the role of the circular economy as a driver of transformation.
Transformation of waste into high added-value materials
We have subjected waste, such as biomass ash, white steel mill slag and fine fractions of concrete construction and demolition waste to upgrading processes by CO₂.
- The result is the creation of new materials with improved properties, resulting in new additions and aggregates suitable for producing cement and concrete with a lower environmental impact.
- These materials offer significant technical improvements, making them attractive solutions for companies in the sector and for society as a whole.
Advanced technologies to accelerate mineralisation
The incorporation of cutting-edge technologies, such as the Supercritical SCCO₂ reactors, enables new methods of carbonation and CO₂ curing to be explored, in order to obtain faster and more efficient mineralisation processes.
Structural changes and increased performance of the materials
The findings of the initiative are particularly relevant. The induced mineralisation has led to profound structural changes in the treated waste:
- reduction in porosity and pore size
- less water absorption
- increased resistance to fragmentation
- increased pozzolanic activity of the materials
The formation of new carbonates, such as calcite, vaterite and aragonite, and of C-S-H gels has increased the reactivity of the materials. This has resulted in significant improvements in the mechanical strength of cements made with carbonated products.
Boosting climate neutrality and the circular economy
These developments show that the carbonate materials obtained are not only sustainable, but also highly functional and potentially comparable to conventional aggregates. This opens up new opportunities for the construction industry and for the development of innovative waste-based solutions.
CIDECAR is an initiative led by the Eduardo Torroja Institute of Construction Sciences (IETcc-CSIC) in conjunction with TECNALIA, and it is financed by the Ministry of Science, Innovation and Universities, the Spanish Research Agency and the European Regional Development Fund (ERDF).