Development of High Performance Shotcrete for Permanent Shotcrete Tunnel Linings (III) (Field Test of Wet-mixed Shotcrete with Powder Types Cement Mineral Accelerator)

Permanent Shotcrete Tunnel Linings 구축을 위한 고성능 숏크리트 개발(III)(시멘트 광물계 분말형 급결제를 사용한 습식숏크리트 현장시험시공)

The use of Shotcrete(Sprayed concrete) for the support of underground excavations was pioneered by the Civil engineering industry. Permanent shotcrete tunnel linings such as Single-shell, NMT(Norwegian Method of Tunnelling) have been constructed in many countries for reducing construction time and lowering construction costs instead of conventional in-situ concrete linings. Among essential technologies for successful application of Permanent Shotcrete Linings, high performance shotcrete having high strength, high durability, better pumpability has to be developed in advance. This paper presents the ideas and the first field test results of wet-mixed Steel Fiber Reinforced Shotcrete(SFRS) with powder types cement mineral accelerator. From the results, wet-mix SFRS with powdered accelerator exhibited good early strength improvement and less rebound ratio compared to the ordinary accelerator.