• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.660-668
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• 2018

The main object of this study was to find a way to operate the marker for simulating a virtual construction using a MR(mixed reality) device. The secondary object was to find a way to extract the form-data from BIM data, and to represent the virtual object by the MR device. A tiny error of scale causes large errors of length because the architectural objects are very large. The scale was affected by the way that the camera of the MR device recognizes the marker. The method of installing and operating the marker causes length errors in the virtual object in the MR system. The experimental results showed that the error factor of the Virtual object's length was 0.47%. In addition, the distance between the markers can be decided through the results of an experiment for the multi-marker tracking system. The minimum distance between markers should be more than 5 m, and the error of length was approximately 23mm. If the represented virtual object must be less than 20mm in error, the particular mark should be installed within a 5 m radius of it. Based on this research, it is expected that utilization of the MR device will increase for the application of virtual construction simulations to construction sites.

• Journal of the Korean Solar Energy Society
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• v.26 no.4
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• pp.9-16
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• 2006

Geothermal-energy has been getting popular as a natural energy source for green buildings these days. Public building with gross area more than $3000m^2$, planned after March, 2005, should spend about 5% of total building cost for equipment run by natural energy source (e.g. geothermal, solar heat, solar power, etc) according to renewable energy promotion law in Korea. As a result geothermal-energy using heat pump system is emerging as a effective alternative for realistic and economic plan although design guidelines and construction code for the system is in progress and technical data is far from sufficient. The quantitative analysis on the performance of geothermal-energy using heat pump system is insufficient for appropriate design of it. In this paper, cooling performance of geothermal-energy using heat pump system of residential and retail etc. mixed-use building has been analyzed on the basis of temperature comparison between inlet and outlet of heat exchangers of the operating system. Additionally, dry-bulb temperature and relative humidity have been measured and analyzed together as an index of indoor thermal environment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.65-68
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• 2005

This paper investigated the engineering properties of cement mortar mixed with more than 2 kinds of sand. For fresh mortar properties, unit volume weight is constant regardless of mixing content and type of sand. An increase in contents of river and crushed sand resulted in an increase in flow, whereas an increase in recycled sand contents reduced flow. Gap between maximum flow in N3C0R0 and minimum flow in N0C0R3 exhibited about $12\%$. Compressive strength at 28 days ranged from 32 to 36 MPa in order for crushed sand, river sand and recycled sand. Mortar with mixed sand along with river sand and crushed sand showed compressive strength comparable to crushed sand. An increase of fraction of recycled sand in mixed sand resulted in a decrease in compressive strength. For drying shrinkage, N0C0R3 had the largest drying shrinkage among various mixture type. The combination of large contents of recycled sand and small contents of river and crushed sand had a large amount of drying shrinkage.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.4
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• pp.419-426
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• 2001

Concrete mix proportioning is a process of selecting the right combination of many materials such as cement, fine aggregates, coarse aggregates, water, and admixtures to make concrete satisfying for specification and cost. In determining proportioning of concrete mixes, code information, specification, and the experience of experts are needed. However, all factors regarding mix proportioning factor cannot be considered. Therefore, the final acceptance depends on concrete quality control test results. The proportioning of concrete mixes and the adjustments are somewhat complicated, time-consuming, and uncertain tasks. In this paper, as a tool to predict the factor of the proportioning of concrete mixes, an artificial neural network is used. To consider the varieties of material properties, the standard mixed table of two companies of ready mixed concrete are used. The results show that neural net works is successfully applied to the prediction of concrete mix proportioning factor.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.206-207
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• 2018

This study is a series of studies intended to derive the improvement of strength concrete quality using an emulsified refined oil (ERCO). In other words, ERCO is used to analyze the improvement degree of the basic properties of ordinary strength concrete by pre-adding the AE Agent on its products. ERCO was also planned to have a mixing ratio of 0, 0.5 %, and the pre-addtion of AE agent mixed with 0, 1, 2, and 3 % of the concrete's mixed ERCO mass. As a result, as the pre-injection of AE agent was increased, the slump, and air contents tended to be improved microscopically, but there was no significant effect. and Compressive strength tends to increase smart-all as the pre-addtion of AE agent increases in concrete, but it does not have a significant effect.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.93-96
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• 2009

This study is to examine a change of quality and a material performance of fiber reinforced cement composite for mass production. It is necessary to make Strain-hardening cementitious composite(SHCC) by batcher plant for ready-mixed concrete and use the performance of SHCC which made based on laboratory level. This study makes a comparative performance of press and mechanics that is the property of Strain-hardening by direct tension. In case of making by batcher plant. This experiment has demonstrated that even if it takes long after being mixed small and compared with the one which made based on laboratory, it has a tendency to be dissatisfied with fiver's dispersion and lower its performance of Strain-hardening. The reason why the material performance of SHCC for mass production went down is through SHCC that mixed sometimes matrix's viscosity and fiber's dispersion.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.176-177
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• 2021

In order to compensate for the defects of concrete made using only Portland cement, three-component powder mixed with blast slag and fly ash, and four-component powder concrete mixed with silica fume are being produced. When each of the admixtures is used alone, the above-described excellent performance is expressed and up to 70% of the powder is used. These technologies are also contributing to the reduction of greenhouse gases under Act on Low Carbon. Green Growth. However, calcium hydroxide is consumed as a stimulator or reaction in the case of silica fume, which causes latent hydroponicity of slag, pozzolane reaction, and silica mixtures represented by fly ash. It is known that the consumption of calcium hydroxide affects the alkalinity of concrete. As a result, the carbonation resistance is significantly lower among the durability of concrete. Research on quantification of such effects is insufficient. In this study, an experiment was conducted to quantify calcium hydroxide of the three-component and four-component powder paste using thermal analysis equipment (DTG), and the effect of the mixing amount was discussed.

• Journal of the Korea Institute of Building Construction
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• v.22 no.2
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• pp.137-148
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• 2022

Recently, in the concrete industry, the development and commercialization of low-carbon products of ready-mixed concrete have emerged as part of the efforts to realize carbon neutrality. This study aims to investigate the current status of environmental product declaration(EPD) of ready-mixed concrete and to analyze the characteristics of carbon emissions by compressive strength, life cycle stage, and region. To this end, the related certification system requiring the calculation of carbon emissions in the concrete industry was analyzed. The target of analyzing the current status of carbon emissions was set as a product of ready-mixed concrete that acquired EPD certification based on the life cycle assessment method. In addition, the trend of carbon emissions according to each characteristic was reviewed by analyzing carbon emissions by the life cycle of ready-mixed concrete products, analyzing carbon emissions by standard, and analyzing carbon emissions by region. As a result, the carbon emissions in the pre-production stage were 99% compared to total carbon emissions., and as it increased from 18MPa to 40MPa, carbon emissions also increased. Even with the same specifications, the carbon emissions in the capital region were higher than in the southern region.

• Journal of the Korean Institute of Educational Facilities
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• v.13 no.3
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• pp.29-36
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• 2006

This research is intended to analyze the tendency and mixed-use of the PFI for the middle schools in Chiba Province, Japan. The Ichikawa 7th middle school has included food supply system, nursery school, auditorium, day service center and care house. It consists of 2 PFIs. The one is middle school, food supply system, nursery school and Auditorium. The other is Day Service Center and Care House for elderly. This is the first mixed-use school by PFI in Japan. The PFI is a very nice tool for the future of our educational environment. But it has weak points, too. This paper analyze the case of Japanese PFI for the better results of Korean BTL systems.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.355-359
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• 2001

Soil is potentially suitale alternatives for use in many environments because many of the conventional materials have been encountered to be shortage due to excessive use by human. However soil without any modifications has been found to be unsuitable for building construction materials. Soil with reinforcement are naturally an answer to these alternatives. Through recent studies about fiber mixed soil, it has been shown that. fiber is a good material to be applied to the building wall. In this study, engineering properties of fiber mixed soil are collectively shown and ideas about use of fiber mixed soil are proposed in addition to the use for building wall,.