• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3C
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• pp.159-165
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• 2010

The problems such as natural resource exhaustion, pollutant emission and waste generation are increasing worldwide with the industrial development. The quantity of the industrial by-product in Korea is 6 million tons a year, and even its basic treatment processes including landfill, incineration and storage have reached their limits. In this study, fly ash and silica fume were applied to shotcrete to develop a method for the reuse of resources and to increase the use of fly ash, which is an industrial waste. An environmental hazard evaluation is a must to actively address the worldwide environmental problems, though. Therefore, an environmental impact assessment was conducted using the chemical content analysis test and heavy metal exudation test, for ten mixtures that were obtained through the pre-mixing and compressive strength tests. The results of the compressive strength test showed that all mixtures satisfied national and international standards. Cr, Cd and Hg were not detected, and Pb was detected only in some cases with fly ash. Cu and As were detected in all mixtures, but all of them satisfied national and international standards.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.97-104
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• 2023

The aim of this study was to produce polymer cement composites (PCCs) composed of polymer dispersion and cement as crack repair materials for RC structures, and to investigate their fundamental properties. The test mixtures for the study were based on EVA and SAE polymer dispersions, and the water-cement ratio was determined while varying the polymer-cement ratio(P/C) in four different levels (20%, 60%, 80%, and 100%) to achieve the desired viscosity of PCCs considering their fillability as crack repair materials. Additionally, silica fume was incorporated into P/C 80% and 100% specimens to enhance their stiffness. The basic properties of PCCs as crack repair materials, such as viscosity, flowability, fillability, tensile strength, elongation, and modulus of elasticity, were examined. The results showed that P/C depending on the type of polymer significantly affected the viscosity and flowability, and appropriate w/c ratios were needed to achieve the desired viscosity for the mixture design with consideration of fillability as crack repair materials for RC structures. All designed mixtures in this study exhibited excellent fillability. The tensile strength and elongation of PCCs satisfied the KS regulation for cement- polymer modified waterproofing coatings. The incorporation of silica fume improved the tensile strength and modulus of elasticity of PCCs. Depending on the type of polymer, mixtures using SAE showed better fundamental properties as crack repair materials for RC structures compared to those using EVA. In conclusion, SAE-based P/C 80% or 100% with the addition of up to 30% silica fume can be recommended as suitable mixtures for crack repair of RC structures.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.495-500
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• 2002

The purpose of this study is to develop and to apply this permanent cement mortar form as one of those system forms to improve existing form's problems. (1) In the fire proof test with combined specimen, the fire proof covering including form section thickness is satisfied with the fire proof criterion. It is considered that form section thickness has no problem (2) The suitable method of normal pressure steam curing for the form's mass production is 4 hours in 65℃ considering production cost, the silica fume admixture is economic.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.4
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• pp.164-168
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• 2003

The initial stage of copper electrodeposition has been known to be very important role for morphology and physical properties after final growth. The factors affecting the nucleation are electrode, current density, electrolyte and temperature. Current studies has illuminated the initial nucleation of copper electrodeposition in the viewpoint of the surface status of electrode and analyzed using EIS and SEM observation

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.10a
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• pp.126-126
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• 2003

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.417-422
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• 2002

Strength and Durability of reinforced concrete exposed at deteriorated environment are decreased by cover spatting and corrosion of reinforcement. The purpose of this paper is to evaluate capacity of strengthening axial member using admixture-modified mortar. To investigate the capacity of strengthened axial member, behavior and strength of strengthening specimens were compared with a monolithic basic specimen. Admixture-modified mortar was prepared with silica fume, zeolite, polymer as cement modifier. From the result of this experiment, strengthening specimens using polymer-modified mortar have apparrent strengthening capacity because of good flexural strength and tensile strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.61-66
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• 2002

The autogenous shrinkage is a important phenomenon of high performance concrete since it may decrease the concrete member's durability by induce crack at early age. So the autogenous shrinkage behavior of high strength concrete was studied according to different replacement ratio of silica fume and fly ash. A linear measurement technique which was introduced by the JCI autogenous commitee was used.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.274-276
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• 2006

This study was researched by measuring the amount how much a welder inhaled the major harmful metals such as Fe, Mn, Cu, Zn and so on which occurred at the welding site during welding work and also by measuring the heavy metal concentration in a welder's blood after the welding. By using the mobile fan, the measure of welding fume and the result were taken.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.497-500
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• 2003

The propose of this study is to discover the extrusion lightweight concrete panel mixing by admixture. The standard of water ratio 50% and weight substitution 0%, 10% by Fly-ash. When the products are manufactured, it is used to maintain its form weight substitution and addition among the viscosity agent each Silica-fume and Hydroxy propyl methyl cellulose. The study is basic properties and performances of extrusion lightweight concrete panels. Testing methods was specific gravity, water absorption, resistance to impact, thermal conductivity, and sound insulation.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.45-49
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• 1995

The fundamental properties of High Performance Concrete(HPC) were studied using high flowable portland cement which was developed at the Sangyong Cement Ind. Co.,Ltd. The results obtained are as follows. (1)The slump of HPC using high flowable portland cement maintains for 120min. (2)Ultra high strength greater than 800kg/$\textrm{cm}^2$ can be designed without using silica fume and other additives. (3)The value of drying shrinkage and adiabatic temperature rise of HPC are less than those of concrete made with OPC.