All participants in the construction process want to achieve sufficient early strength to allow formwork removal as quickly as possible, whether in shotcrete for construction sites or in concrete production.

Durability is of decisive importance and sulfate attack is a constantly occurring and challenging phenomenon

This is especially true in the case of production of precast tunnel lining segments for TBM and rock support applied by sprayed concrete. In excavations in which high sulfate attack is anticipated, it is difficult to fulfill all technical requirements unless appropriate measures regarding the concrete mix design are also taken. For sprayed concrete the use of alkali free accelerators is mandatory to achieve adequate sulfate resistance.

Sika® set Accelerator
SikaRapid® 2
SikaRapid® 505

Construction Site of the Gotthard Base Tunnel