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Waste paper ash, a sustainable alternative to cement and lime for road stabilisation

  • ACCIONA is working to demonstrate the viability of this solution as part of the European PaperChain project, focused on recovering paper industry waste for use in other sectors
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ACCIONA is coordinating the European PaperChain project which, with a budget of €7.8 million financed by the H2020 programme, focuses on recovering wastes from the paper industry and reusing them in the construction, mining and chemicals sectors.

The project includes five real-scale demonstration schemes in a variety of operating environments. One of these is in Spain and involves studies of the viability of using waste paper ash from the Saica energy recovery plant in El Burgo de Ebro to replace cement and lime in three test sections of stabilised soil and soil cement.

This ash is currently the main waste generated by the paper recycling industry so its recovery will help to achieve its“zero waste” target.  At the same time, its use would lead to significant reductions in the carbon footprint of highway construction by replacing cement and lime, both significant sources of CO2, with waste originally destined for landfill.

A one-kilometre section of road surface on Calle La Balsa in Villamayor de Gállego (Zaragoza) is the first section chosen to test this solution. A layer of Type-3 stabilised soil (S-EST3) has been created using 5% waste paper ash instead of cement and finished with a dual-treatment asphalt surface.

The aim of this pilot was to verify an increase in the durability of these types of roads and their environmental safety through long-term monitoring, significantly improving the conditions of this road by modifying the road surface and asphalt.

A second test section has subsequently been carried out in Ejea de los Caballeros (Zaragoza), stabilising (S-EST2) a one kilometre stretch of an unpaved road in the Los Boalares natural park on the outskirts of this town. In this case, 3% fly ash has been added to the existing clay soil in order to achieve significant savings in maintenance, which is important in an area with an extensive network of rural roads with intensive agriculture and livestock activities and the associated heavy machinery traffic.

ACCIONA and Saica have been the leading partners in the PaperChain pilot study in Spain, which also counts on collaboration and technical support from the Technical University of Catalonia (UPC), Tecnalia and the regional government of Aragón’s highways laboratory.


See these links for more information about the European PaperChain project:



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