For tunnel and mining applications, Elkem Microsilica® is used in a variety of ways.
In sprayed concrete (shotcrete) mixtures, Elkem Microsilica® particles make the concrete mixture more cohesive, reducing rebound and wastage.  In many underground situations, microsilica’s ability to increase concrete strength and reduce permeability is beneficial. 

Around 5,000 tonnes of Elkem Microsilica® (Products: Emsac® 500 SE & 920 E) have been used in the sprayed concrete mix for the Crossrail project, currently being constructed in London, UK.  Crossrail is Europe’s largest construction project, it involves the construction of 42 km of new rail tunnels and 10 new stations.    

Contact Elkem  for information on use of microsilica in sprayed concrete, and for information on producing precast high performance concrete for tunnelling applications.  See also GroutAid®