ABSTRACT

Mining and chemical industries have investigated Thin Spray-on Liners (TSLs) intensively in the past. Mining suppliers, contractors and universities have been promoting a concept, or better, a vision of so called ‘Thin Support Liners’ (TSLs). It is a wish of the industry that sprayed concrete and mesh could be replaced by these thin liners. All TSLs are meant to be applied in 3–10 mm layers and consist of a certain polymer content. EFNARC (Experts for Specialized Construction and Concrete Systems is an European federation which unites national associations and companies involved in concrete repair, flooring, sprayed concrete and the protection and repair of tunnel and mining constructions) changed the meaning of the abbreviation "TSL" to "Thin Spray-on Liner" in 2008. This definition change included a clear reduction to the expectations regarding TSLs. Even though TSLs give a certain amount of surface support, they act more as sealant. Today the usage is mainly accepted in coal mines in certain countries, even though some applications in kimberlite or shaft sinking have shown success. Now Normet is introducing a new product called TamCrete SSL a ‘Structural Support Liner’ to the tunneling and mining industry. This new product is introduced as a spray applied, rapid curing, non-toxic resin based support liner for mining environments.

The paper will cover the basics of TamCrete SSL including key mechanical figures and application methods. The paper will also show field test which indicate its waterproofing characteristics. These tests were first carried out as a part of master's thesis and based on these tests the waterproofing characteristics of a cured product seem to be good.

INTRODUCTION

For decades the underground construction industry has used shotcrete for rock support in tunnels. However, shotcrete takes time to cure which slows down the excavation process. In addition shotcrete forms cracks during curing and water might funnel into the tunnel through these cracks. Now Normet Oy has brought a new kind of Thin Sprayed Liner on the market. This material is called TamCrete SSL (Structural Support liner).

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