The new technology is focused on developing concrete with hardness of over 100 MPa (Megapascals), suitable for the construction of high speed train tunnels.

FCC and Sando, operating as a consortium, have achieved accreditation for a type of high performance concrete to be used in building tunnel voussoirs. Both companies are completing work on the longest high speed train tunnel in Andalusia (in southern Spain, between the towns of Sorbas and Barranco de los Gafarillos).

These construction companies needed superior performance from the concrete given that the geological formation of the land in which the Sorbas tunnel has been built is complex, containing both faults and anhydrites.

The technological innovation of these two Spanish companies is derived from previous research into different compositions of concrete, and the creation of a formula leading to hardness of over 100 MPa. To achieve this they’ve made unusual additions such as silica fumes and cutting edge polycarboxylate additives. The resulting concrete represents a substantial technological improvement for tunnel construction in unstable geographical formations.

What’s more, this new type of concrete has also provided efficiency improvements given that form removal can take place more quickly (the removal of the support panels after the concrete has set). This lets builders complete the infrastructure more quickly.