Expansive concrete phenomenon

HOREX, an initiative to improve the lifetime and operability of hydropower plants

Hydroelectric power R&D Engenharia Science

The HOREX project - an acronym for Hormigones Expansivos (Expansive Concretes) - was created by Iberdrola to investigate the phenomenon of the chemical expansion of concrete, which was almost unknown and which is a great challenge for dams worldwide due to the difficulties in controlling it, as it can affect the functionality for which the dams were designed and built, not only during the maintenance of the structures but also during their construction.


Iberdrola's commitment to researching the phenomenon of the chemical expansion of concrete arose 15 years ago at the San Esteban dam, located in Orense, when members of the team in charge of monitoring the dam began to notice anomalies in its behaviour. At that time, there were no studies or clear action strategies in the world to monitor and diagnose what was happening in a dam that was suspected to be undergoing expansion, which is a type of natural deterioration that concrete can undergo. This implies that the useful life of the material decreases substantially as it initiates a degradation process due to the appearance of a chemical reaction between the concrete's own components in the presence of water.

The project was promoted and led by Iberdrola's Innovation and Hydroelectric Generation divisions, with the participation of the Eduardo Torroja Institute of Construction Sciences (CSIC), the School of Civil Engineering of Catalonia, and PRINCIPIA engineering.

A multidisciplinary group of professionals ranging from engineers to geologists to mathematicians came together to try to establish a clear strategy to deal with the suspicion that one of its structures has the phenomenon of chemical expansion

This commitment to research and innovation obtained great results that now allow Iberdrola's professionals to determine whether the components of the concrete used for future dams will be reactive and to what degree to select them so that expansion does not occur. In the Támega project - one of the largest hydroelectric projects carried out in Europe in the last 25 years - this knowledge has been used during its construction with the aim of neutralising a possible expansion of the concrete.