The steel black slag and the residual foundry sand represent one of the main waste streams generated in the Basque metal industry. A major challenge that requires an advanced response, both from the technical side and from the environmental point of view (search for new high added value uses in detriment to the deposition in landfills).
Although for many years the black steel slags have been partially used in certain construction applications (mainly as base and sub-bases for roads), this project opens a new working line, aimed to use them in precast concrete applications.
Foundry waste sand (belonging to sand moulds and cores) is right now in a different situation, managed mainly through final landfill disposal.
The increasing interest in making the construction sector more environmentally friendly, promotes the development of the ECOPAVIN project, which counts with the participation of a group of leading Basque construction companies.
The incorporation of black steel slag has been tested in substitution to natural aggregates, which mixed with waste sands from specific casting processes achieve improved mechanical properties, reaching values 50% higher than those presented by the conventional concrete, which assures a better long-term durability.
The initial project results can be considered very positive, allowing the introduction of more sustainable waste management and recovery alternatives for the iron and steel industry.
In addition to closing the cycle of critical waste streams in a more appropriate way, the project is also aimed at introducing the latest sustainable concepts emerged within the construction sector: the novel target of reducing air pollution by absorbing nitrogen oxides, which is an additional value to this type of next generation concretes
