Browse > Article
http://dx.doi.org/10.7474/TUS.2019.29.6.532

Comparison of the Characteristics of Mix Design and the Performance of Shotcrete Used in Expressway Tunnel Construction Sites  

Lee, Sangdon (Korea Expressway Corporation Research Institute)
Publication Information
Tunnel and Underground Space / v.29, no.6, 2019 , pp. 532-541 More about this Journal
Abstract
Even though shotcrete is a main support for securing the stability of tunnel, the performance of shotcrete is not properly checked due to various difficulties arisen from the characteristics of materials themselves which constitute shotcrete, such as steel fibers and accelerators, and the on-site quality control. In this study, the actual conditions of shotcrete applied to expressway tunnel construction sites were tried to find out, and then some improvement was tried to derive. For this purpose, the characteristics of steel fibers and accelerators supplied to the expressway construction sites were investigated. Also, shotcrete specimens were prepared at the tunnel sites and performance tests were carried out. For steel fiber, domestic production states were investigated, and carbon content and tensile strength were measured using the steel fibers collected in the construction sites. For three types of accelerators such as aluminate, cement mineral and alkali-free, basic properties and total amount of alkali contents were analyzed. Shotcrete specimens were prepared using on-site shotcrete machine with regard to mix designs and types of accelerators. Using these specimens, uniaxial compression tests and flexural tests were performed. As the results, compressive strength, flexural strength, flexural toughness, and etc. were compared with types of acclerators and mix designs.
Keywords
Shotcrete; Performance of shotcrete; Steel fiber; Accelerator; Mix design;
Citations & Related Records
연도 인용수 순위
  • Reference
1 European Federation of Producers and Applicators of Specialist Products for Structures (EFNARC), 1996, European Specification for Sprayed Concrete, p. 30.
2 Korea Expressway Corporation, 2016, Research report - Development of Methods for Improved Performance of Shotcrete Considering Tunnel Construction Process.
3 Korea Expressway Corporation, 2018, Expressway Construction Guide Specification - EXCS 27 30 00 Support for tunnel.
4 Korean Agency for Technology and Standards, 2002, KS D 3554 : Low carbon steel wire rods, p. 5.
5 Korean Agency for Technology and Standards, 2004, KS L 5120 : Method of chemical analysis of Portland cement, p. 66.
6 Korean Agency for Technology and Standards, 2014, KS F 2560 : Chemical admixtures for concrete, p. 25.
7 Korean Agency for Technology and Standards, 2015, KS F 2565 : Standard test method for tension test of steel fibers for concrete, p. 3.
8 Norwegian Concrete Association - Committee Sprayed Concrete, 1993, Sprayed Concrete for Rock Support - Technical Specification and Guidelines, p. 74.