• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.338-350
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• 2010

As existing materials for ground reinforcement, chemical grout material using cementitous materials and waterglass was used. But many problems in terms of ground reinforcement effects were implicated. In this study, for development and applicability verification of new materials, viscosity, fluidity, permeability, Self-Leveling, keeping of drilled hole, antiwashout underwater, resistance of water (groundwater dilution and minimize material eluting) and the early strength and long-term strength characteristics of developed materials was confirmed, and material standards, and establishing construction standards for the various model tests were conducted. As a result, high viscosity, flowability, permeability and keeping of drilled hole characteristics are excellent, in addition to the early strength properties, dilution does nat occur to groundwater, including groundwater is available for dealing with environmental issues. Application of basic and reinforcement method by Filler function in addition to structure can also or development of a new concept can be expected. In addition, middle and large-diameter drilled shaft, micropile, ground anchors, soil-nailing, steel pipes multi-grouting reinforcement for cement injection process could be used enough to even be considered.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.2
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• pp.3031-3038
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• 1973

The aggregate materials being scottored in districts of the country were investigated to provide the data to the Consturction worker who are working without quality tests of construction materials in the small scale land consolidation, farm building construction and new village Construction projects in the country. Also results of the survey will be helpful to those who want to devise a succerrful plan in concrete execution by means of specifying a standard and technical treatment of construction materials.

• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.653-660
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• 2015

Technologies for reducing construction duration are key factors in nuclear power plant construction projects, as a reduction in construction duration at the construction phase leads to a reduction in construction cost and an increase in profits through the early operation of the nuclear power plant. To analyze the constructability of the height of single-layer placement of formwork for the Reactor Containment Building (RCB) exterior wall through lateral pressure according to the height of concrete placement, the deformation criteria for formwork, and a new form design, 'MIDAS GEN (hereinafter referred to as MIDAS)' is used in this study. The cost and workload of formwork are derived according to the unit of height of the RCB exterior wall. Based on the result, it was found that the higher the RCB exterior wall, the higher the material cost, and the less the construction duration and the less the total number of formwork layers. Based on this result, it is believed that the material cost and the construction duration can be appropriately determined according to the formwork height.

• Journal of the Korea Concrete Institute
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• v.25 no.2
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• pp.195-200
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• 2013

New thermal crack control system for mass concrete was developed to increase quality and to save construction period and cost. The principle of this system is that the curing water having proper temperature is supplied automatically to the surface of mass concrete member to keep the temperature difference between center and surface of concrete less than generally recommended temperature difference ($20^{\circ}C$). Mock-up test was conducted to investigate the validity of newly developed curing system. As a result, no crack was founded in the specimen using automated curing system developed in this study, while many cracks occurred in another specimen without automated curing system. It was also confirmed that the strength and the durability of the concrete cured by automated curing system were improved.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.233-244
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• 2009

A new bridge scour countermeasure using geobags and recycled aggregates which is more stable and economical than existing methods is proposed, and its stability was verified through material tests. PP short staple nonwoven geotextile and PET long staple nonwoven geotextile produced in Korea were selected, and a series of strength tests and a test of hydraulic characteristics were conducted to determine a suitable geotextile for geobags. A series of leaching test was also conducted to assess the potential environmental risk of recycled concrete produced in Korea when it is utilized as a material for protecting bridge piers against scour.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.103-104
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• 2018

Recently, in addition to greening of roof and artificial soil, Rootproofing to prevent damage to the waterproof layer and structures by roots is recognized as an important task. Therefore, various related products and construction methods have been developed and applied in the field. However, in the case of synthetic polymer-based sheets most commonly used in domestic construction sites, Most are produced using 100% new materials that are not suitable for green trends such as resource conservation and environmental protection. Therefore, in this study, we developed TPO sheet using recycled material, which is a technology that can secure eco-friendliness by utilizing recycled resources. As a result of the evaluation of tensile performance of the TPO sheet according to the recycled material content, The tensile strength of the specimens with the recycled content of 50 ~ 70% was the highest, The elongation rate of the specimen with the recycled content of 30 ~ 40% was the best.

• Magazine of the Korean Society of Agricultural Engineers
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• v.14 no.1
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• pp.2503-2519
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• 1972

The studies were carried out to find the cause and the quantitative evaluation of sea dike materials loss which is occured during the period of construction works for the tideland reclamation projects on the west coast of Korea. Major subjects to studies were to establish the typical relationships between the tidal flow and the movement of dike materials, the tidal-flow and the erosion, the dike materials and the ratio of material movement(losses), construction methods and the ratio of materials movement (losses). Based on the above subjects, the studies were made for the purpose of obtain the following informations; (1) Collecting and evaluaing the data of dike material losses due to foundation settlement, from designed existing dikes on the west coast. (2) By the field investigation at A-San Sea Dike, Pyong Taek Project, the Comparison would be made by the relationships between the tide velocity and the movement of dike foundation under the natural conditions and the period of construction so that find out the relationship between the dike materials of foundation situation and settlements. With regard to the dike construction works, it is so difficult to calculate the exact quantity of material losses due to the foundation settlements. The major factors that affect the settlement losses of the dike materials are: (1) Topographical variation (2) Swepting the sectional area of dike by the tide velocity. (3) Dumping riprap to the outerside of dike during the period of construction works. (4) Sectional area losses by the cause of occurence of the new tide channels. (5) material losses by the heavy storms. (6) Consolidation settlement by the foundation weakness. (7) Material losses by the earth materials by tide flow. Most hi호 material losses were occured by the Consolidation settlement due to the foundation weakness, the maximum tide velocities due to decrease the cross sectional area of the gaps and erosion of foundation due to the range of tide, Inner and outerside of dike, or dike material loses due to the tide flow. Final conclusion would be obtained by the continuous measurement of consolidation settlement at the stage of final clusure of the dike. (It is scheduled to close on the end of 1972) However, intermediate conclusion can be introduced as follows: (1) The estimation of material(losses) during the period of construction works for the existing sea-dikes up to date were only empirical. The material losses at the general closure for design was estimated at 10% of the riprap, 20% of the earth materials, and 20% of the riprap, 40% of the earth materials at the final closure of the dike. The final closure estimated double quantity to the general closure, but it is still doubt. (2) The ratio of consolidation settlements was found smaller than the calculated quantity. It can be foreseen that settlement speeds is higher thom the calculated speeds. (3) The movement of dike foundation under the natural conditions were not so depends on the geological conditions of the foundation. (4) When the tide velocities was estimated 100 at the normal tide, it was estimated 125 at the high tide and 55 at the low tide. The tide velocities at the low tide shows apparently lower than the high tide and the higher velocities at the deep water depth.

• Korean Journal of Construction Engineering and Management
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• v.4 no.4 s.16
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• pp.69-79
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• 2003

About 93$\%$ of domestic teal estate construction firms registered as the end of 2001 recorded net profits of only less than 500 million won(including firms in the red) for the term. As a result of having analyzed the ratios of sales costs and the structural ratios of sales costs for the past 10 years, it was found that there have been great changes in structural ratios of sales costs. Material costs and labor costs have gradually decreased, but outsourcing costs of processing have greatly increased. In order to find activity points which are fundamental to cost control, the methods of new activity based cost management have been pursued. The characteristics of real estate construction industry lie in the fact that contract prices (sales in) are fixed and amounts of profits differ depending on the use of costs. In order to create maximum profits from fixed contract prices, the new activity based cost management has been proposed. The control of operation budgets and management costs is designed to control their schedules and expenses in different respects. Operation budgets ate executed with specific activities and management costs are controlled as a form of material costs, labor costs, out sourcing costs and expenses which are details of expenditure. In order to execute them by using the methods of new activity based cost management, first of all, we have to analyze what activity drivers ale and how much added values such activities can create. It is considered as a method of cost management which is necessary far the survival management of real estate construction industry.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1112-1117
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• 2005

Construction cost index is generally used to estimate the new project cost based on past construction data and to adjust contract cost when the price change of various articles and items of expenditure composing the contract occurs. In Korea, it is mostly used for adjustment of construction contract cost due to fluctuation of prices. However index adjustment rate which is used for adjustment of construction contract cost had some problems in calculating cost index of each expenditure item that could not reflect properly the change of construction cost. For supplementing these problems, the research of developing construction cost index has been executed. Through the precedent research, these problems were partially resolved but still remain. Therefore this research proposes method of making cost index that utilizes representative items of labor, material, and equipment by analyzing bill of quantity of road construction, through analysis and comparison of precedent study. By using this method, it is expected to solve problems which were not reflected in precedent studies.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.171-174
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• 2009

The standard estimation system, used to estimate the predetermined cost of construction work, is measured by the standard and typical construction methods and field conditions. And the standard estimation system is applied to basic data for the measuring of construction cost, such as the consumed quantity of material, labor hours, and machinery cost. However it does not reflect sufficiently for the diversity and reality of constructions work Therefore, this study is recognized the necessity of new cost estimation models for the rational construction cost estimation. To improve estimation technique and construction ability, it was analyzed labor hours, production volume based on the work crew in construction work.