By Lynda Myer
In order to advancing the extension of Toulouse’s metro Line B, the team responsible is preparing to commission the TBM.
Construction of the underground structures of Connexion Ligne B (CLB), which include two single-tube tunnels, each 250m long and with an internal diameter of 4.66m, which form a double metro track with a reduced right-of-way under the Canal du Midi, is up to a consortium of Bessac, GTM Sud-Ouest TP GC and Soletanche Bachy France.
The TBM, named Clémence Isaure, is due to install 2,850 tunnel segments, whereas the segments will be made from Bessac’s low carbon Exegy concrete, using locally sourced metakaolin. Bessac says for that, thanks to the support of Vinci Construction and Soletanche Bachy’s materials departments, for the first time 55% of the cement clinker used in the concrete has been replaced by a mixture of limestone filler and metakaolin.
Considering that the CO2 emissions is linked to the concrete used for the segments, this work reduces the emission by almost 40% compared with traditional concrete.
According to Bessac: “The Exegy concrete meets client performance requirements in terms of strength class (C40/50), exposure class ensuring durability of reinforcement (carbon dioxide attack) XC2 and chemical attack XA1.”
