• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.369-370
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• 2009

This study aims to find an optimum mix proportions for high-performance shotcrete using industrial by-product from power plants. Compressive strengths of various mix proportions with varying amount of fly ash were verified if they meet the required limits.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.427-428
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• 2009

In order to utilize fly ash as a shotcrete material, this research conducted a heavy-metal leaching test to inspect the influence on environmental. The measured amount of the heavy metals in the leachate was well below the suggested guidelines from Korea and U.S.A.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.323-324
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• 2010

The purpose of this study was to investigate alkali-silica reaction of accelerating agents in shotcrete. The test was performed with accelerating agents (aluminate, alkali-free, cement based mineral admixture) in the Type I cement. As a test result, using the nonreactive aggregates, detrimental expansion due to alkali-silica reaction doesn't occurred regardless of equivalent alkali contents of accelerating agent.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.373-378
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• 2003

The cement-based composites have relatively low tensile strength and toughness. The fiber addition is one of the most important ways of increasing the toughness of concrete. The steel fibers have been used conventionally in the shotcrete of tunnel lining. Recently, the structural synthetic fibers were developed and used frequently in some actual tunnel shotcreting in foreign countries. Now types of synthetic fibers have been developed in this study. The purpose of this study is to explore the strength and toughness characteristic of the concrete reinforced with synthetic fibers developed in this study. The result were compared with those of steel fiber reinforced concrete. It is seen that the performance of synthetic fiber reinforced concrete is good as much as that of steel fiber reinforced concrete, while the synthetic fibers have advantages in corrsion resistance and economy.

• Journal of Industrial Technology
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• v.33 no.A
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• pp.93-99
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• 2013

Shotcrete has been referred to as gunite, pneumatically applied mortar or concrete, sprayed concrete or mortar. There are sound reasons why sprayed mortar is one of the best portland cement based material for repairing old concrete structures. However, it is difficult to find the research results on the latex-modified mortar nevertheless on the impact of air onto the fresh and hardened properties of latex-modified mortar. So, the main experimental program included strength test, slump test, rapid chloride permeability test, image analysis for air void system, and chemical attacks with the main experimental variables of latex content, fine aggregate content, water-cement ratio, and air foamer content.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.89-96
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• 2001

A concrete lining of NATM tunnel is the final product of a process that involves planning and evaluation of user needs, geotechnical investigations, analysis of ground-lining interaction, construction, and observations and modifications during construction. The designer must consider the lining in context of the many function, construction, and geotechnical requirements. Also, the loss of supporting capacity of shotcrete lining due to poor rock qualities and shotcrete erosion must be considered. The values, shapes, and estimating methods of rock load and water pressure are very different with every designers. Estimating methods of rock loads used in the design of NATM tunnel concrete lining are investigated. Numerical analyses are done in various conditions. And the rock loads estimated from radial stress and plastic zone are compared respectively.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1536-1539
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• 2009

In this paper, The Ready-mixed Shotcrete which Factory with automatic production system is made Materials using synthetic fiber is evaluated the field application. Result of whole test, synthetic fiber(PP, PVA) is indicated almost equal result of steel fiber by rebound rate, compressive strength and bending test. especially, PP fiber(40mm, 12kg) is showed that bending strength and toughness is better than steel fiber, also I reason in that field application of synthetic fiber(PP, PVA) is proved.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.841-844
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• 2006

Recently, tunnels being constructed in korea with the increased construction of highways, high-speed railways and hydro structure. shotcrete and spray is one of the major processes in that construction. So general Shotcrete and spray has many problems on strength property, environmental pollution and human body noxiousness as the use of accelerater. However, In this paper using HES-LMS(High Early Strength Latex Modified Spray) without accelerater can solve problems which are mentioned above. problems that the hish early cement has can be solved by modifying material with latex. Therefore HES-LMS mortar is Classify by High performance and High ability. Analysis according to the variables such as W/C, Latex content and sand content is conducted. Studied about mechanical characteristic of material such as each parameter characteristic, and rebound characteristic is completed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.2
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• pp.185-194
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• 1998

This paper shows a case study on quality confirmation and maintenance monitoring of the tunnel underpassing the Han River. First of all, when it comes to the quality confirmation, soil investigation techniques and shotcrete core test will be improved. On the construction stages, quality control procedures are needed. Second, on the maintenance monitoring, it is the main tool to control stability and safety of the tunnel structures throughout the construction period. On the geotechnical monitoring instrumentation, some considerations such as installation of monitoring sections in time, immediate base readings, adequate reading frequency, etc - shall be improved.

• Computers and Concrete
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• v.29 no.5
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• pp.279-283
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• 2022

The seismic analytic collapse fragility of soil nail wall structures with a shotcrete concrete covering is investigated in this paper. The finite element modeling process has been well described. The fragility function evaluates the link between ground motion intensities and the likelihood of reaching a specific level of damage. The soil nail wall has been subjected to incremental dynamic analysis (IDA) from medium to strong ground vibrations. The nonlinear dynamic analysis of the soil nail wall uses a set of 20 earthquake ground motions with varying PGAs. PGD is utilized as an intensity measure, the numerical findings demonstrate that the soil nailing wall reaction is particularly sensitive to earthquake intensity measure (IM).