• 한국건설순환자원학회논문집
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• 제2권2호
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• pp.93-100
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• 2006

Building materials are trending toward environmental materials nowadays and the market share of those is growing. So those researches and developments for environmental property are proceeding now. The main properties of environmental products are far infrared emission, negative ion emission, electro magnetic wave shielding, and anti fungus, these products are used with shape of mortar, and spray on the finish material. But There are not much researches for the concrete, main material in construction field, with those functional properties. So in this research we evaluated slump, compressive strength and air content as basic properties for concrete using functional materials of sericite, wood pattern sand stone, carbon black and nanometric silver solution and functional properties like far infrared emission, negative ion emission, electro magnetic wave shielding, and anti fungus. The results were as follows. The most useful material in the functional materials was carbon black. Sericite and nanometric silver solution had a little effect on functional property, so it was difficult to apply to concrete, and wood pattern sand stone had a high functional property but low compressive strength, can be applied to a factory product. Anti fungus of the concrete using nanometric silver solution was not clear but if those specimens were aged in $CO_2$ gas for a long time it might apparent.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권2호
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• pp.10-16
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• 2017

Recently, the gap between demand and supply of natural aggregate has increased owing to the depletion of aggregate sources. Therefore, policy support is necessary for the stable supply of aggregate resources. Public and construction works experience problems when they do not receive a steady supply of aggregate. Further, instabilities in aggregate supply lead to increases in aggregate prices, and consequently construction costs. As a result, the likelihood of poor construction using low-grade aggregate increases. It is therefore crucial to put measures in place that deal with these issues. This study aims to reduce the load imposed by aggregate use on the environment by recycling soil dredged from sewage ducts to reduce the gap between supply and demand of fine aggregate. The dredged soil is assessed using an applicability test for quality characteristics and solidification with basic properties. This study aims to secure the safety of dredging soil and solidified objects through interior physical and chemical analyses and to utilize it as a base material for concrete solidification in the future.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.896-901
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• 2009

A Soil Nail is a structural element which provides load-transfer to the ground in excavation reinforcement applications. The nail may simply consist of a steel tendon, but most commonly the tendon is encapsulated in a cement grouted body to provide corrosion protection and improved load- transfer to the ground. For temporary excavation support in a congested urban area, the steel bar of Soil Nails should be removed to get permission of the private land to install Soil Nails. Several removable nail systems were developed and evaluated by pull-out load tests. The Soil Nail pull-out tests were performed on five nails installed in soft and hard rock at a 00 housing-redevelopment area in seoul. Two nails are plastic socket type and two are complex socket type mixed steel and plastic. The nail was 0.1mm in diameter, 4m long. In this study verification tests, and steel bar removing tests of plastic socket type nails and complex socket type nails were performed and presented.

• Advances in environmental research
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• 제1권2호
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• pp.125-142
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• 2012

Clean development mechanism (CDM) validity study was conducted to suggest better and more adaptable CDM scenario on water treatment plant (WTP). Potential four scenarios for CDM project; improvement of intake pumping efficiency, hydro power plant construction, solar panel construction and system optimization of mechanical mixing process were evaluated on S-WTP in Korea. Net present value (NPV) of each scenario was estimated based on sensitivity analysis with the variable factors to investigate the CDM validity percentile. Hydro power plant construction was the best option for CDM business with 97.76% validity and $1,127,069 mean profit by 9,813 $tonsCO_2e$/yr reduction. CDM validity on improvement of intake pumping efficiency was 90.2% with $124,305 mean profit by huge amount of $CO_2$ mitigation (10,347 $tonsCO_2e$/yr). System optimization of mechanical mixing process reduced 15% of energy consumption (3,184 $tonsCO_2e$/yr) and its CDM validity and mean profit was 77.25% and $23,942, respectively. Solar panel construction could make the effect of 14,094 $tonsCO_2$ mitigation annually and its CDM validity and mean profit was 64.68% and $228,487, respectively.

• 한국환경과학회지
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• 제14권8호
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• pp.785-792
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• 2005

In order to reduce roadside and indoor air pollution for volatile organic compounds VOC), it may be necessary to apply photocatalyst-coated construction materials. This study evaluated the technical feasibility of the application of $TiO_2$ photocatalysis for the removal of VOC present in roadside or indoor air. The photocatalytic removal of five target VOC was investigated: benzene, toluene, ethyl benzene and o,m,p-xylenes. Variables tested for the current study included ultraviolet(UV) light intensity coating materials, relative humidity (RH), and input concentrations. Prior to performing the parameter tests, adsorption of VOC onto the current experiment was surveyed, and no adsorption was observed. Stronger UV intensity provided higher photocatalytic destruction(PCD) efficiency of the target compounds. For higher humidity, higher PCD efficiency was observed. The PCD efficiency depended on coating material. Contrary to certain previous findings, lower PCD efficiencies were observed for the experimental condition of higher input concentrations. The current findings suggested that the four parameters tested in the present study should be considered for the application of photocatalyst-coated construction materials in cleaning VOC of roadside or indoor air.

• Geomechanics and Engineering
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• 제7권1호
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• pp.105-131
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• 2014

In this paper, the effects of variability of smear zone characteristics induced by installation of prefabricated vertical drains on the preloading design are investigated employing analytical and numerical approaches. Conventional radial consolidation theory has been adopted to conduct analytical parametric studies considering variations of smear zone permeability and extent. FLAC 2D finite difference software has been employed to conduct the numerical simulations. The finite difference analyses have been verified using three case studies including two embankments and a large-scale laboratory consolidometer with a central geosynthetic vertical drain. A comprehensive numerical parametric study is conducted to investigate the influence of smear zone permeability and extent on the model predictions. Furthermore, the construction of the trial embankment is recommended as a reliable solution to estimate accurate smear zone properties and minimise the post construction settlement. A back-calculation procedure is employed to determine the minimum required waiting time after construction of the trial embankment to predict the smear zone characteristics precisely. Results of this study indicate that the accurate smear zone permeability and extent can be back-calculated when 30% degree of consolidation is obtained after construction of the trial embankment.

• 한국환경과학회지
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• 제17권12호
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• pp.1363-1372
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• 2008

In this study, long term semi distributed hydrologic model SWAT-K(Korea) is applied to the Seolma-Cheon watershed to analyze the hydrological components. Seolma-Cheon watershed has been operated as the test watershed of Korea Institute of Construction Technology for 13 years. Therefore it has an enough hydrologic data to analyze the hydrologic characteristics of small watershed. Especially, for the proper runoff analysis of steep watershed, calibration is performed reflecting the regression equation of slope and slope length. The simulated discharge shows good agreement with the observed one and the simulated evapotranspiration and groundwater discharge also show satisfactory results. Finally we presents the ratio of major hydrologic components for 3 years with those obsrved ones. This study is the basic research for future analyses such as relationship between hydrologic components and vegetation, watershed sediment nonpoint sources discharge etc.

• 한국소음진동공학회논문집
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• 제15권11호
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• pp.1311-1317
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• 2005

In environmental Impact assessment, noise impact assessment usually consists of three stages-surveying the existing noise levels by measurements, predicting noise levels induced by construction works and predicting noise levels after the completion of a project. The distance-attenuation relation of a point source, which has been used to predict the noise level due to its simplicity does not consider complex acoustic phenomena like multi-reflection, -diffraction and -absorption due to complex topographic configuration of buildings and terrains. For the consideration of such physical complexities. a noise mapping tool is adopted to produce a series of noise maps, which are those for the present, tot the works of construction and for the future. For accurate noise mapping, acoustical and topographic Information is used. Standard sound power levels and directivities of various construction equipments are need and scheduling of construction processes and locations of the equipments should be provided. In the case of exceeding legal limit, mitigation measures are applied to satisfy the legal limits and subsequent noise map is obtained and checked.

• Smart Structures and Systems
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• 제24권4호
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• pp.459-474
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• 2019

This study develops a novel recursive algorithm to significantly enhance the computation efficiency of a recently proposed stochastic subspace identification (SSI) methodology based on an alternative stabilization diagram. Exemplified by the measurements taken from the two investigated office buildings, it is first demonstrated that merely one sixth of computation time and one fifth of computer memory are required with the new recursive algorithm. Such a progress would enable the realization of on-line and almost real-time monitoring for these two steel framed structures. This recursive SSI algorithm is further applied to analyze 20 months of monitoring data and comprehensively assess the environmental effects. It is certified that the root-mean-square (RMS) response can be utilized as an excellent index to represent most of the environmental effects and its variation strongly correlates with that of the modal frequency. More detailed examination by comparing the monthly correlation coefficient discloses that larger variations in modal frequency induced by greater RMS responses would typically lead to a higher correlation.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.784-791
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• 2022

Tack coat is a thin layer of asphalt between the existing pavement and asphalt overlay. During construction, insufficient tack coat layering can later cause surface defects such as slippage, shoving, and rutting. This paper proposed a method for tack coat inspection improvement using an unmanned aerial vehicle (UAV) and deep learning neural network for automatic non-uniform assessment of the applied tack coat area. In this method, the drone-captured images are exploited for assessment using a combination of Mask R-CNN and Grey Level Co-occurrence Matrix (GLCM). Mask R-CNN is utilized to detect the tack coat region and segment the region of interest from the surroundings. GLCM is used to analyze the texture of the segmented region and measure the uniformity and non-uniformity of the tack coat on the existing pavements. The results of the field experiment showed both the intersection over union of Mask R-CNN and the non-uniformity measured by GLCM were promising with respect to their accuracy. The proposed method is automatic and cost-efficient, which would be of value to state Departments of Transportation for better management of their work in pavement construction and rehabilitation.