• Infraestructuras

We create concrete with steel from end-of-life tires 

Advantages include, cutting CO2, saving water, reducing the contamination of asphalt, and helping to preserve forests. In addition, each dose achieves better fiber distribution thanks to their smaller diameter and length.

Sacyr Engineering and Infrastructure, together with Sacyr Green, and in collaboration with Flexofibers, have established a strategic positioning, with new concrete reinforcing fibers that replace traditional methods of reinforcement, made out of end-of-life tires (ELTs). Their first application has been to a slope on the exterior of the Zumelegi tunnel in Elorrio (Biscay). 

These innovative fibers play a key role in achieving circularity, applying disruptive technology to their extraction from tires, and in particular their cleaning, conditioning, and sorting.

The processes used maintain their most special properties, like flexible steel, with a tensile strength of 2,500 mega pascals, and they are 100% recyclable.

The concrete created using these fibers is certified by the Instituto de Ciencias de la Construcción Torroja to promote the development of the circular economy.



Studies involved a series of tests to gauge the compression behavior of the new steel-fiber concrete and check its level of energy absorption. In total, eight measuring cylinders were tested, four for each type. As for the results after 28 days of tensile strength tests, an average of 37 MPa was reached .

These types of fibers are similar to those that appear in polymers, with the advantage of steel and tire recycling. 
Other advantages include, for example, cutting CO2, saving water, reducing the contamination of asphalt, and helping to preserve forests. In addition, each dose achieves better fiber distribution thanks to their smaller diameter and length.

In conclusion, Sacyr Ingeniería e Infraestructuras, with the active participation of Cavosa and its Innovation department, together with Sacyr Green and Flexofibers, have delivered fibers made from recycled ELT tires, offering the incredible advantages mentioned before, becoming a potential competitor in terms of fibers used to reinforce concrete.

We are now in the finishing straight, refining the product so it can be applied in any project in the present and future, as we strive to incorporate the circular economy as an essential element of the business. 

  • Concrete
  • Steel

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