Macro-synthetic fibre technology new focus for underground construction

Effective December 31, 2004, Degussa Admixtures of Cleveland, Ohio, will withdraw from the supply of steel fibres for the underground construction environment. Degussa Admixtures has been involved with the supply of fibre reinforcement through a strategic alliance with S.I. Concrete Systems since 1998.

“This is a business decision driven by our confidence in the emerging macro-synthetic fibre technology for underground construction applications,” explained Mike Rispin, director, Canadian Division and Underground Construction for Degussa Admixtures.

The industry has seen a proliferation of fibre-reinforced shotcrete in underground applications in North America over the last decade. Emerging high performance macro-synthetic fibres, such as S.I. Concrete Systems’ recently-introduced ENDUROTM fibre, provide superior toughness and ductility for ground support applications. ENDURO fibres are becoming the preferred reinforcing for shotcrete ground support in mining and tunneling applications throughout North America.

With soaring steel reinforcing costs and limited supply, these polymer fibres are replacing the more traditional steel fibres in mining ground support shotcrete. The macro-synthetic fibres can carry an increased load after cracking, unlike steel fibres. Macro-synthetic fibres are added to shotcrete at about 8 kg/m3 versus up to 60 kg/m3 for steel fibres. The safe and easy handling and economic advantages with increased performance make these fibres the best alternative to conventional reinforcing methods, such as welded wire mesh or steel fibres.