• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.429-432
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• 2008

Large area members such as foundation concrete of underground structures in power plants have an effect on structural stability and durability of the structure due to danger of crack occurrence and shrinkage crack that occur owing to the difference of temperature by heat of hydration between inside and outside of the members at initial age. And a construction for waterproofness is performed additionally to protect marine structures from osmosis of seawater because the structures adjoin below the surface of sea. So, if a rise of the heat of hydration, crack, and corrosion of bars are controled effectively using a composite such as fluosilicate salt in concrete production process of a initial construction, expenses are cut down and construction hours are reduced by securing durability through improvement of watertightness. The property tests of adiabatic temperature by hydration are carried out at initial age about standard concrete and test concrete using a fluosilicate salt composite to evaluate an effect on improvement of watertightness for concrete structures in this study. And the experiments such as a permeability test of hardened concrete, a water absorption test, a compression strength test and a elongation test are carried out and the results from these are described.

• 한국건축시공학회지
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• 제9권2호
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• pp.69-76
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• 2009

Recently, the twenty-first century is called "the age of localization and regionalization" in Korea. So, local government should need to keep balance between the existing administrative management and new management strategies based on CEO's mind in order to deal with the situation of such that(the age of localization and regionalization) and improve efficiency of public service. In addition, they build public buildings after that they should operate and maintain them regularly. However, Korea local governments have tried to run many projects to expand insufficient local finance that was only for profit oriented public projects without considering management. Therefore, this paper is a basic study to establish and suggest the reasonable operation plan for local government by examining and reviewing actual operation condition in the public buildings. With the evaluation method which is demanded from public construction management to introduce a civil management technique manages an investment mind standard and management basis of assessment, proposes 8 sides of financial affairs, real estate maintenance and facility management, achievement evaluation, environmental safe crisis management, judiciary and explanation responsibility with base.

• 한국의류학회지
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• 제10권3호
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• pp.37-48
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• 1986

The purpose of this study was to analyze 'the natural groupings' of subjects in order to classify highly similar somatotype for clothing construction. The sample for the study was drawn randomly out of senior high school boys in Seoul urban area. The sample size was 425 boys between age 16 and 18. Cluster analysis was more concerned with finding the hierarchical structure of subjects by three dimensional distance of stature. bust girth and sleeve length. The groups forming a partition can be subdivided into 5 and 6 sets by the hierarchical tree of the given subjects. Ward's Minimum Variance Method was applied after extraction of distance matrix by the Standardized Euclidean Distance. All of the above data was analyzed by the computer installed at Korea Advanced Institute of Science and Technology. The major findings, take for instance, of 16 age group can be summarized as follows. The results of cluster analysis of this study: 1. Cluster 1 (32 persons means $18.29\%$ of the total) is characterized with smaller bust girth than that of cluster 5, but stature and sleeve length of the cluster 1 are the largest group. 2. Cluster 2 (18 Persons means $10.29\%$ of the total) is characterized with the group of the smallest stature and sleeve length, but bust girth larger than that of cluster 3. 3. Cluster 3(35persons means $20\%$ of the total) is classified with the smallest group of all the stature, bust girth and sleeve length. 4. Cluster 4(60 persons means $34.29\%$ of the total) is grouped with the same value of sleeve length with the mean value of 16 age group, but the stature and bust girth is smaller than the mean value of this age group. 5. Cluster 5(30 persons means $17.14\%$ of the total) is characterized with smaller stature than that of cluster 1, and with larger bust girth than that of cluster 1, but with the same value of the sleeve length with the mean value of the 16 age group.

• 한국건축시공학회지
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• 제3권3호
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• pp.83-90
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• 2003

This study examines the material characteristics of fibers and their influences on reinforced concrete through the tests of reinforced concrete by the types of fibers including non-reinforced, steel, polypropylene and cellulose fibers and the test of compressive strength and reinforced concrete beam without shear reinforcement and consequently it obtains the following conclusions. As a result of conducting compressive strength by the types of specimens, fiber reinforced specimen with the highest compressive strength value at 28 days of age was cellulose fiber reinforced specimen as 280.4kgf/$\textrm{cm}^2$ and steel fiber specimen had the highest compressive strength of 250.7kgf/$\textrm{cm}^2$ at 180 days of age. In case of non-reinforced specimen, its compressive strength was 277.4kgf/$\textrm{cm}^2$ at 28 days of age and 273.1kgf/$\textrm{cm}^2$ at 180 days of age. Comparing the compressive strength of non-reinforced specimen to that fiber reinforced specimen showed that the compressive strength of fiber reinforced specimen was lower in the passage of age and the results of this experiment showed no effects of fiber reinforcement. As a result of testing reinforced concrete beam without shear reinforcement, ductility factors of specimens were 4.67 for non-reinforced specimen, 8.18 for steel fiber reinforced specimen, 6.20 for polypropylene fiber reinforced specimen and 5.49 for cellulose reinforced specimen, and it is found that steel fiber reinforced specimen was highest. When non-reinforced specimen and steel fiber reinforced specimen were compared, steel fiber reinforced specimen had higher ductility factor of about 75.2% than that of non-reinforced specimen.

• 한국건축시공학회지
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• 제2권4호
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• pp.169-176
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• 2002

To study of binder and fine aggregate a lot of replacement fly-ash concrete, initial characteristics, standard environment of curing temperature $20^{\circ}C$, hot-weather environment, cold weather environment of curing temperature $5^{\circ}C$. Flash concrete tested slump, air contest, setting and Hardening concrete valuated setting period of form, day of age 3, 7, 28 compression strength in sealing curing. Underwater curing specimen compression strength of age 3. 7, 28day used strength change accordingly fly-ash concrete curing temperature. Purpose of study is consultation materials in field that variety of fly-ash replacement concrete mix proportion comparison and valuation. (1) Setting test result, fly-ash ratio of replacement higher delay totting time. Same volume of fly-ash ratio of replacement is lower fly-ash ratio of replacement fine aggregate delay setting time. Setting test in curing temperature $35^{\circ}C$ over twice fast setting in curing temperature $20^{\circ}C$ and all specimen setting delay in curing temperature $5^{\circ}C$. F40 specimen end of setting about 30 time. (2) Experiment result age 28day compression strength more fisher plan concrete then standard environment in curing temperature $20^{\circ}C$, cold weather environment in curing temperature $5^{\circ}C$, most strength F43 is hot-weather environment in curing temperature $35^{\circ}C$ replacement binder 25%, fine aggregate 15%. (3) Hot-weather environment replacement a mount of fly-ash is a same of plan concrete setting period of form. Age 28day compression strength replacement a mount of fly-ash more hot-weather concrete then plan concrete.

• 한국건축시공학회지
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• 제17권4호
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• pp.331-339
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• 2017

본 연구는 시멘트 종류, 폴리머 종류, 폴리머 시멘트비, 도장두께를 변화시켜 만든 PCS 도장철근의 시멘트 콘크리트에 대한 부착강도 시험을 실시하여 PCS 도장철근의 부착강도에 영향을 미치는 양생재령과 도장두께에 대하여 평가하고자 하였다. 또한 부착강도 시험결과로 얻어진 최적배합으로 만든 PCS 도장철근을 사용하여 철근콘크리트 보를 제작하여 휨 응력 시험을 실시하여 간접적으로 부착성을 평가하였다. 시험결과, PCS 도장철근의 부착강도는 양생재령 7일과 도장두께 $100{\mu}m$에서 최대치를 나타냈는데, 이는 보통 철근의 1.52배 및 에폭시 도장철근의 1.58배였다. 또한 PCS 도장철근을 사용한 철근콘크리트 보의 최대 파괴하중은 보통철근의 최대 파괴하중의 81.1%~102.3% 범위였으며, 에폭시 도장철근의 최대 파괴하중의 98.4%~124.1% 범위로 나타났다. 본 연구결과, 도장두께 $100{\mu}m$, 폴리머 종류 EVA, 폴리머 시멘트비 80%, 양생재령 7일 조건으로 만든 PCS 도장철근은 실제 건설현장의 철근콘크리트 구조물의 도장철근으로 활용할 수 있는 가능성을 확인하였다.

• 한국도로학회:학술대회논문집
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• 한국도로학회 2006년도 춘계학술대회 논문집
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• pp.77-84
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• 2006

• 한국대기환경학회지
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• 제30권6호
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• pp.555-568
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• 2014

The construction equipment is one of the major sources for hazardous air pollutants in Korea, and the its management has been of great concern recently. The objective of this study was to estimate each contribution of emission of construction equipments according to their production year, electric power consumption and type. To achieve this goal, we developed pollutant emission factors for the machineries manufactured after 2009, which are excluded from the present framework of Korean air pollutants inventory, CAPSS. More than 800 data obtained from emission investigations were utilized for the estimation. Compared with the previous estimation, the scheme used this study was modified to incorporate new emission factors as well as to include the corresponding activity data. Such improvement allow us to gain more detailed emission informations which are better characterized by specifications of construction equipments. The total amount of pollutants emitted from construction equipments in 2011 were estimated as 126.8, 7.0, 58.3, and 17.0 kton for $NO_x$, PM, CO, and VOC, respectively. The estimation results indicate that the increase in the emission of equipments is significantly related to their age and power consumption. The emissions of the older ones manufactured from 1992~1996 were estimated to be the contribution ranged from 23.7% to 26.8%, whereas the newer ones (2009~2011) showed the attributions of 11.3~21.5%. In addition, the results show that the emission of each equipment was increased with the increase in the electric power consumption of engine, probably due to their average output power. Among the nine types of machinery compared, excavators and forklifts were investigated to contribute relatively higher emissions in the level of 39.8~44.0% and 32.0~34.2%, respectively.

• Journal of Construction Engineering and Project Management
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• 제1권2호
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• pp.28-36
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• 2011

Risk management is popularly and widely used in various industries to handle uncertainty that can negatively affect their businesses. While in the current Information-Technology oriented age, software packages are designed to assist in carrying out risk management processes, the construction industry does not seem to have software that is tuned to its specific characteristics and processes. Therefore, this study first explores the types of software that are commonly used for risk management in the Singapore construction industry. Also, using one-sample t-test, it is tested if the software programs used in the construction industry have effectively catered the needs of the users. For the analysis, a survey questionnaire was developed and the representatives from 34 companies participated in the survey. Furthermore, this study also makes use of the current risk management framework defined in ISO31000 to design a risk management software algorithm that can suit the needs for the Singapore construction industry. The results from this study will contribute to identifying strategic areas, in terms of use of risk management software, on which the industry needs to focus, ultimately enhancing their performance of risk management.

• 한국구조물진단유지관리공학회 논문집
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• 제7권2호
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• pp.135-140
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• 2003

As a construction technique is developed recently, the construction space and construction period are considered to important matters. Especially, in case of construction period, several method is proposed for strength control in the construction field. However there are very little strength control models for application of internal condition. The purpose of this study is to develop a strength control model for application of variety internal condition at construction field. The results are as follows ; 1) According to the results of compressive strength of concrete evaluated by logistic curve and proposed curve, proposed curve is applicable of construction field because there is similar relation with logistic curve. 2) It is shown that the construction period is shortened by reduction of the formwork removal time, because a predicted compressive strength of using the new curve is higher than the proposed compressive strength of standard.